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[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
.TH LIBPNG 3 "June 27, 2013"
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.SH NAME
[libpng16] Bump version to 1.6.3beta09
2013-06-18 18:23:54 +00:00
libpng \- Portable Network Graphics (PNG) Reference Library 1.6.3beta09
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.SH SYNOPSIS
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fB
#include <png.h>\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP
Imported from libpng-1.4.0beta7.tar
2006-06-16 12:52:03 +00:00
\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
Imported from libpng-1.4.0beta7.tar
2006-06-16 12:52:03 +00:00
\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP
\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBpng_uint_32 png_get_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*red_X\fP\fB, double \fP\fI*red_Y\fP\fB, double \fP\fI*red_Z\fP\fB, double \fP\fI*green_X\fP\fB, double \fP\fI*green_Y\fP\fB, double \fP\fI*green_Z\fP\fB, double \fP\fI*blue_X\fP\fB, double \fP\fI*blue_Y\fP\fB, double \fI*blue_Z\fP\fB);\fP
[devel] Bump version to libpng-1.4.0beta72
2009-07-30 20:39:00 +00:00
[devel] Fixes to rgb_to_gray and cHRM XYZ APIs
2011-08-25 21:19:44 +00:00
\fBpng_uint_32 png_get_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fI*int_red_X\fP\fB, png_fixed_point \fP\fI*int_red_Y\fP\fB, png_fixed_point \fP\fI*int_red_Z\fP\fB, png_fixed_point \fP\fI*int_green_X\fP\fB, png_fixed_point \fP\fI*int_green_Y\fP\fB, png_fixed_point \fP\fI*int_green_Z\fP\fB, png_fixed_point \fP\fI*int_blue_X\fP\fB, png_fixed_point \fP\fI*int_blue_Y\fP\fB, png_fixed_point \fI*int_blue_Z\fP\fB);\fP
\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.4.0beta33.tar
2008-08-20 22:25:21 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Bump version to libpng-1.4.0beta72
2009-07-30 20:39:00 +00:00
\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
[devel] Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
2011-01-22 14:51:19 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP
[devel] Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
2011-01-22 14:51:19 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr\fP\fB);\fP
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fB/* This function is really an inline macro. \fI*/
[libpng16] Imported from libpng-1.6.0beta34.tar
2012-12-19 22:06:56 +00:00
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP
Imported from libpng-1.2.9beta3.tar
2006-02-24 12:30:16 +00:00
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fB/* This function is really an inline macro. \fI*/
[libpng16] Imported from libpng-1.6.0beta34.tar
2012-12-19 22:06:56 +00:00
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.2.6rc1.tar
2004-08-04 11:34:52 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.2.6rc1.tar
2004-08-04 11:34:52 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
[devel] Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. Added png_get_current_row_number and png_get_current_pass_number for the benefit of the user transform callback. Added png_process_data_pause and png_process_data_skip for the benefit of progressive readers that need to stop data processing or want to optimize skipping of unread data (e.g. if the reader marks a chunk to be skipped.)
2011-01-22 23:36:34 +00:00
\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-1.2.2beta3.tar
2002-03-07 04:08:00 +00:00
\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
[libpng] Added synopses for new png_image functions to the manual.
2011-11-08 05:50:05 +00:00
\fBint png_image_begin_read_from_file (png_imagep \fP\fIimage\fP\fB, const char \fI*file_name\fP\fB);\fP
\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP
\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, png_size_t \fIsize\fP\fB);\fP
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBint png_image_finish_read (png_imagep \fP\fIimage\fP\fB, png_colorp \fP\fIbackground\fP\fB, void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
[libpng] Added synopses for new png_image functions to the manual.
2011-11-08 05:50:05 +00:00
\fBvoid png_image_free (png_imagep \fIimage\fP\fB);\fP
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBint png_image_write_to_file (png_imagep \fP\fIimage\fP\fB, const char \fP\fI*file\fP\fB, int \fP\fIconvert_to_8bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
[libpng16] Imported from libpng-1.6.0beta28.tar
2012-08-29 19:03:09 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap)\fP\fB);\fP
[libpng] Added synopses for new png_image functions to the manual.
2011-11-08 05:50:05 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
Imported from libpng-1.2.0beta3.tar
2001-05-18 09:54:50 +00:00
\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
[devel] Added exported png_longjmp() function.
2010-02-19 15:54:53 +00:00
\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP
Imported from libpng-1.4.0beta11.tar
2006-08-19 18:59:24 +00:00
\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
Imported from libpng-1.2.0beta3.tar
2001-05-18 09:54:50 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
\fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
[devel] Bump version to libpng-1.4.0beta72
2009-07-30 20:39:00 +00:00
Imported from libpng-1.2.9beta3.tar
2006-02-24 12:30:16 +00:00
\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP
\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Update documentation
2010-07-30 00:09:18 +00:00
\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBvoid png_set_check_for_invalid_index(png_structrp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
[libpng16] Bump version to 1.6.0beta16
2012-03-03 04:38:50 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
\fBvoid png_set_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIred_X\fP\fB, double \fP\fIred_Y\fP\fB, double \fP\fIred_Z\fP\fB, double \fP\fIgreen_X\fP\fB, double \fP\fIgreen_Y\fP\fB, double \fP\fIgreen_Z\fP\fB, double \fP\fIblue_X\fP\fB, double \fP\fIblue_Y\fP\fB, double \fIblue_Z\fP\fB);\fP
[devel] Fixes to rgb_to_gray and cHRM XYZ APIs
2011-08-25 21:19:44 +00:00
\fBvoid png_set_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fIint_red_X\fP\fB, png_fixed_point \fP\fIint_red_Y\fP\fB, png_fixed_point \fP\fIint_red_Z\fP\fB, png_fixed_point \fP\fIint_green_X\fP\fB, png_fixed_point \fP\fIint_green_Y\fP\fB, png_fixed_point \fP\fIint_green_Z\fP\fB, png_fixed_point \fP\fIint_blue_X\fP\fB, png_fixed_point \fP\fIint_blue_Y\fP\fB, png_fixed_point \fIint_blue_Z\fP\fB);\fP
Imported from libpng-1.4.0beta33.tar
2008-08-20 22:25:21 +00:00
\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.2beta02.tar
2011-02-19 21:50:17 +00:00
\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP
[master] Add synopsis for png_set_16() to the manual.
2011-02-13 11:56:07 +00:00
[devel] Imported from libpng-1.5.2beta02.tar
2011-02-19 21:50:17 +00:00
\fBvoid png_set_expand_16 (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.2.9beta8.tar
2006-03-09 05:35:59 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Update documentation
2010-07-30 00:09:18 +00:00
\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP
\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Added png_set_longjmp_fn to scripts/*.def and moved it from libpngpf.3 to libpng.3 since it is exported.
2009-11-21 04:06:56 +00:00
\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP
[devel] Update documentation
2010-07-30 00:09:18 +00:00
\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP
[libpng16] Bump version to 1.6.0beta33
2012-12-10 01:20:34 +00:00
\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
\fBvoid png_set_scale_16 (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP
\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP
[devel] Updated manual about the new API additions
2011-04-01 05:16:50 +00:00
\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
\fBvoid \fP\fIpng_set_text_compression_method\fP\fB, (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod)\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
[devel] Updated documentation of png_set|get_tRNS().
2011-01-15 16:25:25 +00:00
\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
[manual] Updated libpng.3 synopses to agree with scripts/symbols.def
2011-01-22 22:27:39 +00:00
\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.2.6rc1.tar
2004-08-04 11:34:52 +00:00
\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP
\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP
\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP
\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP
\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP
\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
Imported from libpng-1.4.0beta7.tar
2006-06-16 12:52:03 +00:00
\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.SH DESCRIPTION
The
.I libpng
library supports encoding, decoding, and various manipulations of
the Portable Network Graphics (PNG) format image files. It uses the
.IR zlib(3)
compression library.
[devel] Changed "libpng.txt" to "libpng-manual.txt" in libpng.3
2010-10-17 17:55:04 +00:00
Following is a copy of the libpng-manual.txt file that accompanies libpng.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
.SH LIBPNG.TXT
[devel] Changed "libpng.txt" to "libpng-manual.txt" in libpng.3
2010-10-17 17:55:04 +00:00
libpng-manual.txt - A description on how to use and modify libpng
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
libpng version 1.6.3beta09 - June 27, 2013
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Updated and distributed by Glenn Randers-Pehrson
Imported from libpng-1.2.8rc1.tar
2004-11-24 13:50:16 +00:00
<glennrp at users.sourceforge.net>
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Copyright (c) 1998-2013 Glenn Randers-Pehrson
[devel] Revise references to zlib-libpng license
2009-06-24 15:27:36 +00:00
[devel] Imported from libpng-1.4.0beta66.tar
2009-06-27 02:46:52 +00:00
This document is released under the libpng license.
[devel] Revise references to zlib/libpng license
2009-06-25 18:43:50 +00:00
For conditions of distribution and use, see the disclaimer
[devel] Revise references to zlib-libpng license
2009-06-24 15:27:36 +00:00
and license in png.h
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Based on:
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
libpng versions 0.97, January 1998, through 1.6.3beta09 - June 27, 2013
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Updated and distributed by Glenn Randers-Pehrson
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Copyright (c) 1998-2013 Glenn Randers-Pehrson
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
libpng 1.0 beta 6 version 0.96 May 28, 1997
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Updated and distributed by Andreas Dilger
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Copyright (c) 1996, 1997 Andreas Dilger
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
libpng 1.0 beta 2 - version 0.88 January 26, 1996
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
For conditions of distribution and use, see copyright
notice in png.h. Copyright (c) 1995, 1996 Guy Eric
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
Schalnat, Group 42, Inc.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Updated/rewritten per request in the libpng FAQ
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Copyright (c) 1995, 1996 Frank J. T. Wojcik
December 18, 1995 & January 20, 1996
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Imported from libpng-1.6.0beta04.tar
2011-12-30 02:57:39 +00:00
TABLE OF CONTENTS
I. Introduction
II. Structures
III. Reading
IV. Writing
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
V. Simplified API
VI. Modifying/Customizing libpng
VII. MNG support
VIII. Changes to Libpng from version 0.88
IX. Changes to Libpng from version 1.0.x to 1.2.x
X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
XI. Changes to Libpng from version 1.4.x to 1.5.x
XII. Changes to Libpng from version 1.5.x to 1.6.x
XIII. Detecting libpng
XIV. Source code repository
XV. Coding style
XVI. Y2K Compliance in libpng
[libpng16] Imported from libpng-1.6.0beta04.tar
2011-12-30 02:57:39 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
.SH I. Introduction
This file describes how to use and modify the PNG reference library
[libpng16] Expanded manual paragraph about writing private chunks, particularly about the need to call png_set_keep_unknown_chunks() when writing them.
2013-04-27 23:03:03 +00:00
(known as libpng) for your own use. In addition to this
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
file, example.c is a good starting point for using the library, as
it is heavily commented and should include everything most people
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
will need. We assume that libpng is already installed; see the
INSTALL file for instructions on how to install libpng.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
For examples of libpng usage, see the files "example.c", "pngtest.c",
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
and the files in the "contrib" directory, all of which are included in
the libpng distribution.
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Libpng was written as a companion to the PNG specification, as a way
of reducing the amount of time and effort it takes to support the PNG
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
file format in application programs.
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
The PNG specification (second edition), November 2003, is available as
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
<http://www.w3.org/TR/2003/REC-PNG-20031110/
The W3C and ISO documents have identical technical content.
The PNG-1.2 specification is available at
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
<http://www.libpng.org/pub/png/documents/>. It is technically equivalent
to the PNG specification (second edition) but has some additional material.
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
The PNG-1.0 specification is available
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
Some additional chunks are described in the special-purpose public chunks
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
documents at <http://www.libpng.org/pub/png/documents/>.
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Other information
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
about PNG, and the latest version of libpng, can be found at the PNG home
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
page, <http://www.libpng.org/pub/png/>.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Most users will not have to modify the library significantly; advanced
users may want to modify it more. All attempts were made to make it as
complete as possible, while keeping the code easy to understand.
Currently, this library only supports C. Support for other languages
is being considered.
Libpng has been designed to handle multiple sessions at one time,
to be easily modifiable, to be portable to the vast majority of
machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
to use. The ultimate goal of libpng is to promote the acceptance of
the PNG file format in whatever way possible. While there is still
work to be done (see the TODO file), libpng should cover the
majority of the needs of its users.
Libpng uses zlib for its compression and decompression of PNG files.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Further information about zlib, and the latest version of zlib, can
Imported from libpng-1.0.9beta3.tar
2000-11-23 17:51:42 +00:00
be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The zlib compression utility is a general purpose utility that is
useful for more than PNG files, and can be used without libpng.
See the documentation delivered with zlib for more details.
You can usually find the source files for the zlib utility wherever you
find the libpng source files.
Libpng is thread safe, provided the threads are using different
instances of the structures. Each thread should have its own
png_struct and png_info instances, and thus its own image.
Libpng does not protect itself against two threads using the
Imported from libpng-1.4.0beta35.tar
2008-10-06 15:16:17 +00:00
same instance of a structure.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
.SH II. Structures
There are two main structures that are important to libpng, png_struct
[devel] Update documentation
2010-07-30 00:09:18 +00:00
and png_info. Both are internal structures that are no longer exposed
in the libpng interface (as of libpng 1.5.0).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The png_info structure is designed to provide information about the
PNG file. At one time, the fields of png_info were intended to be
directly accessible to the user. However, this tended to cause problems
with applications using dynamically loaded libraries, and as a result
Imported from libpng-1.0.7beta11.tar
2000-05-06 19:09:57 +00:00
a set of interface functions for png_info (the png_get_*() and png_set_*()
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
functions) was developed, and direct access to the png_info fields was
deprecated..
[devel] Update documentation
2010-07-30 00:09:18 +00:00
The png_struct structure is the object used by the library to decode a
single image. As of 1.5.0 this structure is also not exposed.
Almost all libpng APIs require a pointer to a png_struct as the first argument.
Many (in particular the png_set and png_get APIs) also require a pointer
to png_info as the second argument. Some application visible macros
defined in png.h designed for basic data access (reading and writing
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
integers in the PNG format) don't take a png_info pointer, but it's almost
always safe to assume that a (png_struct*) has to be passed to call an API
function.
You can have more than one png_info structure associated with an image,
as illustrated in pngtest.c, one for information valid prior to the
IDAT chunks and another (called "end_info" below) for things after them.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The png.h header file is an invaluable reference for programming with libpng.
And while I'm on the topic, make sure you include the libpng header file:
#include <png.h>
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
and also (as of libpng-1.5.0) the zlib header file, if you need it:
#include <zlib.h>
[devel] Update documentation
2010-07-30 00:09:18 +00:00
.SS Types
The png.h header file defines a number of integral types used by the
APIs. Most of these are fairly obvious; for example types corresponding
to integers of particular sizes and types for passing color values.
One exception is how non-integral numbers are handled. For application
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
convenience most APIs that take such numbers have C (double) arguments;
however, internally PNG, and libpng, use 32 bit signed integers and encode
[devel] Update documentation
2010-07-30 00:09:18 +00:00
the value by multiplying by 100,000. As of libpng 1.5.0 a convenience
macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
which is simply (png_int_32).
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
All APIs that take (double) arguments also have a matching API that
[devel] Update documentation
2010-07-30 00:09:18 +00:00
takes the corresponding fixed point integer arguments. The fixed point
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
API has the same name as the floating point one with "_fixed" appended.
[devel] Update documentation
2010-07-30 00:09:18 +00:00
The actual range of values permitted in the APIs is frequently less than
the full range of (png_fixed_point) (-21474 to +21474). When APIs require
a non-negative argument the type is recorded as png_uint_32 above. Consult
the header file and the text below for more information.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
Special care must be take with sCAL chunk handling because the chunk itself
uses non-integral values encoded as strings containing decimal floating point
numbers. See the comments in the header file.
[devel] Update documentation
2010-07-30 00:09:18 +00:00
.SS Configuration
The main header file function declarations are frequently protected by C
preprocessing directives of the form:
#ifdef PNG_feature_SUPPORTED
declare-function
#endif
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
...
#ifdef PNG_feature_SUPPORTED
use-function
#endif
[devel] Update documentation
2010-07-30 00:09:18 +00:00
The library can be built without support for these APIs, although a
standard build will have all implemented APIs. Application programs
should check the feature macros before using an API for maximum
portability. From libpng 1.5.0 the feature macros set during the build
of libpng are recorded in the header file "pnglibconf.h" and this file
is always included by png.h.
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
If you don't need to change the library configuration from the default, skip to
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
the next section ("Reading").
Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
of the build project files in the 'projects' directory simply copy
scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build
systems do not permit easy auto-configuration of the library - they only
support the default configuration.
The easiest way to make minor changes to the libpng configuration when
auto-configuration is supported is to add definitions to the command line
using (typically) CPPFLAGS. For example:
CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
will change the internal libpng math implementation for gamma correction and
other arithmetic calculations to fixed point, avoiding the need for fast
floating point support. The result can be seen in the generated pnglibconf.h -
make sure it contains the changed feature macro setting.
If you need to make more extensive configuration changes - more than one or two
feature macro settings - you can either add -DPNG_USER_CONFIG to the build
command line and put a list of feature macro settings in pngusr.h or you can set
DFA_XTRA (a makefile variable) to a file containing the same information in the
form of 'option' settings.
A. Changing pnglibconf.h
A variety of methods exist to build libpng. Not all of these support
reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be
rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
pnglibconf.h and changing the lines defining the supported features, paying
very close attention to the 'option' information in scripts/pnglibconf.dfa
that describes those features and their requirements. This is easy to get
wrong.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
B. Configuration using DFA_XTRA
Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
variant such as 'nawk' or 'gawk', is available. The configure build will
automatically find an appropriate awk and build pnglibconf.h.
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
The scripts/pnglibconf.mak file contains a set of make rules for doing the
same thing if configure is not used, and many of the makefiles in the scripts
directory use this approach.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
When rebuilding simply write a new file containing changed options and set
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
DFA_XTRA to the name of this file. This causes the build to append the new file
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
to the end of scripts/pnglibconf.dfa. The pngusr.dfa file should contain lines
of the following forms:
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
everything = off
This turns all optional features off. Include it at the start of pngusr.dfa to
make it easier to build a minimal configuration. You will need to turn at least
some features on afterward to enable either reading or writing code, or both.
option feature on
option feature off
Enable or disable a single feature. This will automatically enable other
features required by a feature that is turned on or disable other features that
require a feature which is turned off. Conflicting settings will cause an error
message to be emitted by awk.
setting feature default value
Changes the default value of setting 'feature' to 'value'. There are a small
number of settings listed at the top of pnglibconf.h, they are documented in the
source code. Most of these values have performance implications for the library
but most of them have no visible effect on the API. Some can also be overridden
from the API.
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
This method of building a customized pnglibconf.h is illustrated in
contrib/pngminim/*. See the "$(PNGCONF):" target in the makefile and
pngusr.dfa in these directories.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
C. Configuration using PNG_USR_CONFIG
If -DPNG_USR_CONFIG is added to the CFLAGS when pnglibconf.h is built the file
pngusr.h will automatically be included before the options in
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
scripts/pnglibconf.dfa are processed. Your pngusr.h file should contain only
macro definitions turning features on or off or setting settings.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
Apart from the global setting "everything = off" all the options listed above
can be set using macros in pngusr.h:
#define PNG_feature_SUPPORTED
is equivalent to:
option feature on
#define PNG_NO_feature
is equivalent to:
option feature off
#define PNG_feature value
is equivalent to:
setting feature default value
Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
pngusr file you supply override the contents of scripts/pnglibconf.dfa
If confusing or incomprehensible behavior results it is possible to
examine the intermediate file pnglibconf.dfn to find the full set of
dependency information for each setting and option. Simply locate the
feature in the file and read the C comments that precede it.
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
This method is also illustrated in the contrib/pngminim/* makefiles and
pngusr.h.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
.SH III. Reading
We'll now walk you through the possible functions to call when reading
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
in a PNG file sequentially, briefly explaining the syntax and purpose
of each one. See example.c and png.h for more detail. While
progressive reading is covered in the next section, you will still
need some of the functions discussed in this section to read a PNG
file.
.SS Setup
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You will want to do the I/O initialization(*) before you get into libpng,
so if it doesn't work, you don't have much to undo. Of course, you
will also want to insure that you are, in fact, dealing with a PNG
file. Libpng provides a simple check to see if a file is a PNG file.
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
To use it, pass in the first 1 to 8 bytes of the file to the function
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
png_sig_cmp(), and it will return 0 (false) if the bytes match the
corresponding bytes of the PNG signature, or nonzero (true) otherwise.
Of course, the more bytes you pass in, the greater the accuracy of the
prediction.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you are intending to keep the file pointer open for use in libpng,
you must ensure you don't read more than 8 bytes from the beginning
of the file, and you also have to make a call to png_set_sig_bytes_read()
with the number of bytes you read from the beginning. Libpng will
then only check the bytes (if any) that your program didn't read.
(*): If you are not using the standard I/O functions, you will need
to replace them with custom functions. See the discussion under
Customizing libpng.
FILE *fp = fopen(file_name, "rb");
if (!fp)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
fread(header, 1, number, fp);
Imported from libpng-1.0.2b.tar
1999-01-07 03:50:16 +00:00
is_png = !png_sig_cmp(header, 0, number);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!is_png)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
return (NOT_PNG);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
Next, png_struct and png_info need to be allocated and initialized. In
order to ensure that the size of these structures is correct even with a
dynamically linked libpng, there are functions to initialize and
allocate the structures. We also pass the library version, optional
pointers to error handling functions, and a pointer to a data struct for
use by the error functions, if necessary (the pointer and functions can
be NULL if the default error handlers are to be used). See the section
on Changes to Libpng below regarding the old initialization functions.
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
The structure allocation functions quietly return NULL if they fail to
create the structure, so your application should check for that.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_structp png_ptr = png_create_read_struct
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
(PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
user_error_fn, user_warning_fn);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!png_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_infop info_ptr = png_create_info_struct(png_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!info_ptr)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_read_struct(&png_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
(png_infopp)NULL, (png_infopp)NULL);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
If you want to use your own memory allocation routines,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
png_create_read_struct_2() instead of png_create_read_struct():
png_structp png_ptr = png_create_read_struct_2
[devel] Added more about creating and destroying the optional "end_info" structure in the libpng documentation.
2011-04-21 03:20:40 +00:00
(PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
user_error_fn, user_warning_fn, (png_voidp)
user_mem_ptr, user_malloc_fn, user_free_fn);
The error handling routines passed to png_create_read_struct()
and the memory alloc/free routines passed to png_create_struct_2()
are only necessary if you are not using the libpng supplied error
handling and memory alloc/free functions.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
When libpng encounters an error, it expects to longjmp back
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
to your routine. Therefore, you will need to call setjmp and pass
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
your png_jmpbuf(png_ptr). If you read the file from different
[devel] Changed png_struct jmp_buf member name to avoid clash with macro
2011-04-27 19:47:15 +00:00
routines, you will need to update the longjmp buffer every time you enter
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
a new routine that will call a png_*() function.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
See your documentation of setjmp/longjmp for your compiler for more
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
information on setjmp/longjmp. See the discussion on libpng error
handling in the Customizing Libpng section below for more information
on the libpng error handling. If an error occurs, and libpng longjmp's
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
back to your setjmp, you will want to call png_destroy_read_struct() to
free any memory.
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
if (setjmp(png_jmpbuf(png_ptr)))
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_read_struct(&png_ptr, &info_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
&end_info);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
fclose(fp);
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
[devel] Added more about creating and destroying the optional "end_info" structure in the libpng documentation.
2011-04-21 03:20:40 +00:00
Pass (png_infopp)NULL instead of &end_info if you didn't create
an end_info structure.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
If you would rather avoid the complexity of setjmp/longjmp issues,
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
you can compile libpng with PNG_NO_SETJMP, in which case
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
errors will result in a call to PNG_ABORT() which defaults to abort().
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Now you need to set up the input code. The default for libpng is to
use the C function fread(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is
opened in binary mode. If you wish to handle reading data in another
way, you need not call the png_init_io() function, but you must then
implement the libpng I/O methods discussed in the Customizing Libpng
section below.
png_init_io(png_ptr, fp);
If you had previously opened the file and read any of the signature from
the beginning in order to see if this was a PNG file, you need to let
libpng know that there are some bytes missing from the start of the file.
png_set_sig_bytes(png_ptr, number);
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
You can change the zlib compression buffer size to be used while
reading compressed data with
png_set_compression_buffer_size(png_ptr, buffer_size);
where the default size is 8192 bytes. Note that the buffer size
is changed immediately and the buffer is reallocated immediately,
instead of setting a flag to be acted upon later.
[devel] Added description of png_set_crc_action() to the manual.
2011-01-07 03:42:36 +00:00
If you want CRC errors to be handled in a different manner than
the default, use
png_set_crc_action(png_ptr, crit_action, ancil_action);
The values for png_set_crc_action() say how libpng is to handle CRC errors in
ancillary and critical chunks, and whether to use the data contained
therein. Note that it is impossible to "discard" data in a critical
chunk.
Choices for (int) crit_action are
PNG_CRC_DEFAULT 0 error/quit
PNG_CRC_ERROR_QUIT 1 error/quit
PNG_CRC_WARN_USE 3 warn/use data
PNG_CRC_QUIET_USE 4 quiet/use data
PNG_CRC_NO_CHANGE 5 use the current value
Choices for (int) ancil_action are
PNG_CRC_DEFAULT 0 error/quit
PNG_CRC_ERROR_QUIT 1 error/quit
PNG_CRC_WARN_DISCARD 2 warn/discard data
PNG_CRC_WARN_USE 3 warn/use data
PNG_CRC_QUIET_USE 4 quiet/use data
PNG_CRC_NO_CHANGE 5 use the current value
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Setting up callback code
You can set up a callback function to handle any unknown chunks in the
input stream. You must supply the function
[devel] Fixed incorrect examples of callback prototypes in the manual. "png_ptr ptr" should be "png_structp png_ptr"
2011-01-24 14:04:37 +00:00
read_chunk_callback(png_structp png_ptr,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
png_unknown_chunkp chunk);
{
/* The unknown chunk structure contains your
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
chunk data, along with similar data for any other
unknown chunks: */
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
png_byte name[5];
png_byte *data;
png_size_t size;
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
/* Note that libpng has already taken care of
the CRC handling */
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
/* put your code here. Search for your chunk in the
unknown chunk structure, process it, and return one
of the following: */
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
return (-n); /* chunk had an error */
return (0); /* did not recognize */
return (n); /* success */
}
(You can give your function another name that you like instead of
"read_chunk_callback")
To inform libpng about your function, use
png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
read_chunk_callback);
This names not only the callback function, but also a user pointer that
you can retrieve with
png_get_user_chunk_ptr(png_ptr);
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
If you call the png_set_read_user_chunk_fn() function, then all unknown
[libpng16] Better documentation of unknown handling API interactions.
2013-03-02 23:59:43 +00:00
chunks which the callback does not handle will be saved when read. You can
cause them to be discarded by returning '1' ("handled") instead of '0'. This
behavior will change in libpng 1.7 and the default handling set by the
png_set_keep_unknown_chunks() function, described below, will be used when the
callback returns 0. If you want the existing behavior you should set the global
default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
versions of libpng and with 1.7. Libpng 1.6 issues a warning if you keep the
default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
At this point, you can set up a callback function that will be
called after each row has been read, which you can use to control
a progress meter or the like. It's demonstrated in pngtest.c.
You must supply a function
[devel] Fixed incorrect examples of callback prototypes in the manual. "png_ptr ptr" should be "png_structp png_ptr"
2011-01-24 14:04:37 +00:00
void read_row_callback(png_structp png_ptr,
png_uint_32 row, int pass);
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
{
/* put your code here */
}
(You can give it another name that you like instead of "read_row_callback")
To inform libpng about your function, use
png_set_read_status_fn(png_ptr, read_row_callback);
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
[devel] Fix the read/write row callback documentation.
2011-02-16 12:16:31 +00:00
When this function is called the row has already been completely processed and
the 'row' and 'pass' refer to the next row to be handled. For the
non-interlaced case the row that was just handled is simply one less than the
passed in row number, and pass will always be 0. For the interlaced case the
same applies unless the row value is 0, in which case the row just handled was
the last one from one of the preceding passes. Because interlacing may skip a
pass you cannot be sure that the preceding pass is just 'pass-1', if you really
need to know what the last pass is record (row,pass) from the callback and use
the last recorded value each time.
As with the user transform you can find the output row using the
PNG_ROW_FROM_PASS_ROW macro.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Unknown-chunk handling
Now you get to set the way the library processes unknown chunks in the
input PNG stream. Both known and unknown chunks will be read. Normal
behavior is that known chunks will be parsed into information in
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
various info_ptr members while unknown chunks will be discarded. This
behavior can be wasteful if your application will never use some known
chunk types. To change this, you can call:
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.2.6rc1.tar
2004-08-04 11:34:52 +00:00
png_set_keep_unknown_chunks(png_ptr, keep,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
chunk_list, num_chunks);
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
keep - 0: default unknown chunk handling
1: ignore; do not keep
Imported from libpng-1.2.6rc3.tar
2004-08-10 02:50:32 +00:00
2: keep only if safe-to-copy
3: keep even if unsafe-to-copy
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.2.6rc3.tar
2004-08-10 02:50:32 +00:00
You can use these definitions:
PNG_HANDLE_CHUNK_AS_DEFAULT 0
PNG_HANDLE_CHUNK_NEVER 1
PNG_HANDLE_CHUNK_IF_SAFE 2
PNG_HANDLE_CHUNK_ALWAYS 3
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
chunk_list - list of chunks affected (a byte string,
five bytes per chunk, NULL or '\0' if
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
num_chunks is positive; ignored if
numchunks <= 0).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
num_chunks - number of chunks affected; if 0, all
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
unknown chunks are affected. If positive,
only the chunks in the list are affected,
and if negative all unknown chunks and
all known chunks except for the IHDR,
PLTE, tRNS, IDAT, and IEND chunks are
affected.
Imported from libpng-1.2.6rc2.tar
2004-08-08 02:42:49 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Unknown chunks declared in this way will be saved as raw data onto a
list of png_unknown_chunk structures. If a chunk that is normally
known to libpng is named in the list, it will be handled as unknown,
according to the "keep" directive. If a chunk is named in successive
instances of png_set_keep_unknown_chunks(), the final instance will
Imported from libpng-1.2.6rc3.tar
2004-08-10 02:50:32 +00:00
take precedence. The IHDR and IEND chunks should not be named in
chunk_list; if they are, libpng will process them normally anyway.
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
If you know that your application will never make use of some particular
chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Here is an example of the usage of png_set_keep_unknown_chunks(),
where the private "vpAg" chunk will later be processed by a user chunk
callback function:
png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'};
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
png_byte unused_chunks[]=
{
104, 73, 83, 84, (png_byte) '\0', /* hIST */
105, 84, 88, 116, (png_byte) '\0', /* iTXt */
112, 67, 65, 76, (png_byte) '\0', /* pCAL */
115, 67, 65, 76, (png_byte) '\0', /* sCAL */
115, 80, 76, 84, (png_byte) '\0', /* sPLT */
116, 73, 77, 69, (png_byte) '\0', /* tIME */
};
#endif
...
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
[libpng16] Better documentation of unknown handling API interactions.
2013-03-02 23:59:43 +00:00
/* ignore all unknown chunks
* (use global setting "2" for libpng16 and earlier):
*/
png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
/* except for vpAg: */
png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
/* also ignore unused known chunks: */
png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
(int)(sizeof unused_chunks)/5);
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
#endif
Imported from libpng-1.4.0beta33.tar
2008-08-20 22:25:21 +00:00
.SS User limits
The PNG specification allows the width and height of an image to be as
large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
Since very few applications really need to process such large images,
we have imposed an arbitrary 1-million limit on rows and columns.
Larger images will be rejected immediately with a png_error() call. If
[devel] Imported from libpng-1.5.3beta11.tar
2011-06-11 19:22:22 +00:00
you wish to change this limit, you can use
Imported from libpng-1.4.0beta33.tar
2008-08-20 22:25:21 +00:00
png_set_user_limits(png_ptr, width_max, height_max);
to set your own limits, or use width_max = height_max = 0x7fffffffL
to allow all valid dimensions (libpng may reject some very large images
anyway because of potential buffer overflow conditions).
You should put this statement after you create the PNG structure and
before calling png_read_info(), png_read_png(), or png_process_data().
[devel] Revised documentation about png_set_user_limits() to say that it can only be used to reduce the defined limit, and that it also affects png writing.
2011-06-11 02:17:34 +00:00
When writing a PNG datastream, put this statement before calling
png_write_info() or png_write_png().
Imported from libpng-1.4.0beta33.tar
2008-08-20 22:25:21 +00:00
If you need to retrieve the limits that are being applied, use
width_max = png_get_user_width_max(png_ptr);
height_max = png_get_user_height_max(png_ptr);
The PNG specification sets no limit on the number of ancillary chunks
allowed in a PNG datastream. You can impose a limit on the total number
of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
where 0x7fffffffL means unlimited. You can retrieve this limit with
chunk_cache_max = png_get_chunk_cache_max(png_ptr);
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
You can also set a limit on the amount of memory that a compressed chunk
other than IDAT can occupy, with
png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
and you can retrieve the limit with
chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
Any chunks that would cause either of these limits to be exceeded will
be ignored.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
.SS Information about your system
If you intend to display the PNG or to incorporate it in other image data you
need to tell libpng information about your display or drawing surface so that
libpng can convert the values in the image to match the display.
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
From libpng-1.5.4 this information can be set before reading the PNG file
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
header. In earlier versions png_set_gamma() existed but behaved incorrectly if
called before the PNG file header had been read and png_set_alpha_mode() did not
exist.
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
If you need to support versions prior to libpng-1.5.4 test the version number
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
described in the appropriate manual page.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
You give libpng the encoding expected by your system expressed as a 'gamma'
value. You can also specify a default encoding for the PNG file in
case the required information is missing from the file. By default libpng
assumes that the PNG data matches your system, to keep this default call:
png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
or you can use the fixed point equivalent:
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
PNG_FP_1/screen_gamma);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
If you don't know the gamma for your system it is probably 2.2 - a good
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
approximation to the IEC standard for display systems (sRGB). If images are
too contrasty or washed out you got the value wrong - check your system
documentation!
Many systems permit the system gamma to be changed via a lookup table in the
display driver, a few systems, including older Macs, change the response by
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
default. As of 1.5.4 three special values are available to handle common
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
situations:
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
PNG_DEFAULT_sRGB: Indicates that the system conforms to the
IEC 61966-2-1 standard. This matches almost
all systems.
PNG_GAMMA_MAC_18: Indicates that the system is an older
(pre Mac OS 10.6) Apple Macintosh system with
the default settings.
PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
that the system expects data with no gamma
encoding.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
You would use the linear (unencoded) value if you need to process the pixel
values further because this avoids the need to decode and reencode each
component value whenever arithmetic is performed. A lot of graphics software
uses linear values for this reason, often with higher precision component values
to preserve overall accuracy.
The second thing you may need to tell libpng about is how your system handles
alpha channel information. Some, but not all, PNG files contain an alpha
channel. To display these files correctly you need to compose the data onto a
suitable background, as described in the PNG specification.
Libpng only supports composing onto a single color (using png_set_background;
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
see below). Otherwise you must do the composition yourself and, in this case,
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
you may need to call png_set_alpha_mode:
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
#if PNG_LIBPNG_VER >= 10504
png_set_alpha_mode(png_ptr, mode, screen_gamma);
#else
png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
#endif
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
The screen_gamma value is the same as the argument to png_set_gamma; however,
how it affects the output depends on the mode. png_set_alpha_mode() sets the
file gamma default to 1/screen_gamma, so normally you don't need to call
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
png_set_gamma. If you need different defaults call png_set_gamma() before
png_set_alpha_mode() - if you call it after it will override the settings made
by png_set_alpha_mode().
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
The mode is as follows:
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
PNG_ALPHA_PNG: The data is encoded according to the PNG specification. Red,
green and blue, or gray, components are gamma encoded color
values and are not premultiplied by the alpha value. The
alpha value is a linear measure of the contribution of the
pixel to the corresponding final output pixel.
You should normally use this format if you intend to perform
color correction on the color values; most, maybe all, color
correction software has no handling for the alpha channel and,
anyway, the math to handle pre-multiplied component values is
unnecessarily complex.
Before you do any arithmetic on the component values you need
to remove the gamma encoding and multiply out the alpha
channel. See the PNG specification for more detail. It is
important to note that when an image with an alpha channel is
scaled, linear encoded, pre-multiplied component values must
be used!
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
The remaining modes assume you don't need to do any further color correction or
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
that if you do, your color correction software knows all about alpha (it
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
probably doesn't!)
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
PNG_ALPHA_STANDARD: The data libpng produces
is encoded in the standard way
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
assumed by most correctly written graphics software.
The gamma encoding will be removed by libpng and the
linear component values will be pre-multiplied by the
alpha channel.
With this format the final image must be re-encoded to
match the display gamma before the image is displayed.
If your system doesn't do that, yet still seems to
perform arithmetic on the pixels without decoding them,
it is broken - check out the modes below.
With PNG_ALPHA_STANDARD libpng always produces linear
component values, whatever screen_gamma you supply. The
screen_gamma value is, however, used as a default for
the file gamma if the PNG file has no gamma information.
If you call png_set_gamma() after png_set_alpha_mode() you
will override the linear encoding. Instead the
pre-multiplied pixel values will be gamma encoded but
the alpha channel will still be linear. This may
actually match the requirements of some broken software,
but it is unlikely.
While linear 8-bit data is often used it has
insufficient precision for any image with a reasonable
dynamic range. To avoid problems, and if your software
supports it, use png_set_expand_16() to force all
components to 16 bits.
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
PNG_ALPHA_OPTIMIZED: This mode is the same
as PNG_ALPHA_STANDARD except that
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
completely opaque pixels are gamma encoded according to
the screen_gamma value. Pixels with alpha less than 1.0
will still have linear components.
Use this format if you have control over your
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
compositing software and so don't do other arithmetic
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
(such as scaling) on the data you get from libpng. Your
compositing software can simply copy opaque pixels to
the output but still has linear values for the
non-opaque pixels.
In normal compositing, where the alpha channel encodes
partial pixel coverage (as opposed to broad area
translucency), the inaccuracies of the 8-bit
representation of non-opaque pixels are irrelevant.
You can also try this format if your software is broken;
it might look better.
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD;
however, all component values,
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
including the alpha channel are gamma encoded. This is
an appropriate format to try if your software, or more
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
likely hardware, is totally broken, i.e., if it performs
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
linear arithmetic directly on gamma encoded values.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
In most cases of broken software or hardware the bug in the final display
manifests as a subtle halo around composited parts of the image. You may not
even perceive this as a halo; the composited part of the image may simply appear
separate from the background, as though it had been cut out of paper and pasted
on afterward.
If you don't have to deal with bugs in software or hardware, or if you can fix
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
them, there are three recommended ways of using png_set_alpha_mode():
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
screen_gamma);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
You can do color correction on the result (libpng does not currently
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
support color correction internally). When you handle the alpha channel
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
you need to undo the gamma encoding and multiply out the alpha.
png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
screen_gamma);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
png_set_expand_16(png_ptr);
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
If you are using the high level interface, don't call png_set_expand_16();
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
With this mode you can't do color correction, but you can do arithmetic,
including composition and scaling, on the data without further processing.
png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
screen_gamma);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
You can avoid the expansion to 16-bit components with this mode, but you
lose the ability to scale the image or perform other linear arithmetic.
All you can do is compose the result onto a matching output. Since this
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
mode is libpng-specific you also need to write your own composition
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
software.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
If you don't need, or can't handle, the alpha channel you can call
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
png_set_background() to remove it by compositing against a fixed color. Don't
call png_set_strip_alpha() to do this - it will leave spurious pixel values in
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
transparent parts of this image.
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
png_set_background(png_ptr, &background_color,
PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
The background_color is an RGB or grayscale value according to the data format
libpng will produce for you. Because you don't yet know the format of the PNG
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
file, if you call png_set_background at this point you must arrange for the
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
format produced by libpng to always have 8-bit or 16-bit components and then
store the color as an 8-bit or 16-bit color as appropriate. The color contains
separate gray and RGB component values, so you can let libpng produce gray or
RGB output according to the input format, but low bit depth grayscale images
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
must always be converted to at least 8-bit format. (Even though low bit depth
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
grayscale images can't have an alpha channel they can have a transparent
color!)
You set the transforms you need later, either as flags to the high level
interface or libpng API calls for the low level interface. For reference the
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
settings and API calls required are:
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
8-bit values:
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
png_set_expand(png_ptr); png_set_scale_16(png_ptr);
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
If you must get exactly the same inaccurate results
produced by default in versions prior to libpng-1.5.4,
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
instead.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
16-bit values:
PNG_TRANSFORM_EXPAND_16
png_set_expand_16(png_ptr);
In either case palette image data will be expanded to RGB. If you just want
color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
to the list.
Calling png_set_background before the PNG file header is read will not work
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
prior to libpng-1.5.4. Because the failure may result in unexpected warnings or
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
errors it is therefore much safer to call png_set_background after the head has
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
been read. Unfortunately this means that prior to libpng-1.5.4 it cannot be
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
used with the high level interface.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS The high-level read interface
At this point there are two ways to proceed; through the high-level
read interface, or through a sequence of low-level read operations.
You can use the high-level interface if (a) you are willing to read
the entire image into memory, and (b) the input transformations
you want to do are limited to the following set:
PNG_TRANSFORM_IDENTITY No transformation
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to
8-bit accurately
PNG_TRANSFORM_STRIP_16 Chop 16-bit samples to
8-bit less accurately
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
samples to bytes
PNG_TRANSFORM_PACKSWAP Change order of packed
pixels to LSB first
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_EXPAND Perform set_expand()
PNG_TRANSFORM_INVERT_MONO Invert monochrome images
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
PNG_TRANSFORM_SHIFT Normalize pixels to the
sBIT depth
PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
to BGRA
PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
to AG
PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
to transparency
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
[devel] Added high-level PNG_TRANSFORM_GRAY_TO_RGB transform.
2009-06-29 22:30:00 +00:00
PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples
to RGB (or GA to RGBA)
[devel] Added expand_16 suppport to the high level interface.
2011-05-09 00:46:51 +00:00
PNG_TRANSFORM_EXPAND_16 Expand samples to 16 bits
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
(This excludes setting a background color, doing gamma transformation,
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
quantizing, and setting filler.) If this is the case, simply do this:
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
png_read_png(png_ptr, info_ptr, png_transforms, NULL)
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
where png_transforms is an integer containing the bitwise OR of some
set of transformation flags. This call is equivalent to png_read_info(),
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
followed the set of transformations indicated by the transform mask,
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
then png_read_image(), and finally png_read_end().
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
(The final parameter of this call is not yet used. Someday it might point
to transformation parameters required by some future input transform.)
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
You must use png_transforms and not call any png_set_transform() functions
when you use png_read_png().
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
After you have called png_read_png(), you can retrieve the image data
with
row_pointers = png_get_rows(png_ptr, info_ptr);
where row_pointers is an array of pointers to the pixel data for each row:
png_bytep row_pointers[height];
If you know your image size and pixel size ahead of time, you can allocate
row_pointers prior to calling png_read_png() with
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
if (height > PNG_UINT_32_MAX/(sizeof (png_byte)))
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
png_error (png_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
"Image is too tall to process in memory");
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
if (width > PNG_UINT_32_MAX/pixel_size)
png_error (png_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
"Image is too wide to process in memory");
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
row_pointers = png_malloc(png_ptr,
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
height*(sizeof (png_bytep)));
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
for (int i=0; i<height, i++)
row_pointers[i]=NULL; /* security precaution */
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
for (int i=0; i<height, i++)
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
row_pointers[i]=png_malloc(png_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
width*pixel_size);
Imported from libpng-1.0.9beta3.tar
2000-11-23 17:51:42 +00:00
png_set_rows(png_ptr, info_ptr, &row_pointers);
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
Alternatively you could allocate your image in one big block and define
row_pointers[i] to point into the proper places in your block.
If you use png_set_rows(), the application is responsible for freeing
row_pointers (and row_pointers[i], if they were separately allocated).
If you don't allocate row_pointers ahead of time, png_read_png() will
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
do it, and it'll be free'ed by libpng when you call png_destroy_*().
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS The low-level read interface
If you are going the low-level route, you are now ready to read all
the file information up to the actual image data. You do this with a
call to png_read_info().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_read_info(png_ptr, info_ptr);
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
This will process all chunks up to but not including the image data.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
This also copies some of the data from the PNG file into the decode structure
for use in later transformations. Important information copied in is:
1) The PNG file gamma from the gAMA chunk. This overwrites the default value
provided by an earlier call to png_set_gamma or png_set_alpha_mode.
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
2) Prior to libpng-1.5.4 the background color from a bKGd chunk. This
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
damages the information provided by an earlier call to png_set_background
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
resulting in unexpected behavior. Libpng-1.5.4 no longer does this.
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
3) The number of significant bits in each component value. Libpng uses this to
optimize gamma handling by reducing the internal lookup table sizes.
4) The transparent color information from a tRNS chunk. This can be modified by
a later call to png_set_tRNS.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Querying the info structure
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Functions are used to get the information from the info_ptr once it
has been read. Note that these fields may not be completely filled
in until png_read_end() has read the chunk data following the image.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_IHDR(png_ptr, info_ptr, &width, &height,
&bit_depth, &color_type, &interlace_type,
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
&compression_type, &filter_method);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
width - holds the width of the image
in pixels (up to 2^31).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
height - holds the height of the image
in pixels (up to 2^31).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
bit_depth - holds the bit depth of one of the
image channels. (valid values are
1, 2, 4, 8, 16 and depend also on
the color_type. See also
significant bits (sBIT) below).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
color_type - describes which color/alpha channels
are present.
PNG_COLOR_TYPE_GRAY
(bit depths 1, 2, 4, 8, 16)
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
PNG_COLOR_TYPE_GRAY_ALPHA
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
(bit depths 8, 16)
PNG_COLOR_TYPE_PALETTE
(bit depths 1, 2, 4, 8)
PNG_COLOR_TYPE_RGB
(bit_depths 8, 16)
PNG_COLOR_TYPE_RGB_ALPHA
(bit_depths 8, 16)
PNG_COLOR_MASK_PALETTE
PNG_COLOR_MASK_COLOR
PNG_COLOR_MASK_ALPHA
[devel] In the manual, describe the png_get_IHDR() arguments in the right order.
2011-01-21 14:31:29 +00:00
interlace_type - (PNG_INTERLACE_NONE or
PNG_INTERLACE_ADAM7)
compression_type - (must be PNG_COMPRESSION_TYPE_BASE
for PNG 1.0)
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
filter_method - (must be PNG_FILTER_TYPE_BASE
for PNG 1.0, and can also be
PNG_INTRAPIXEL_DIFFERENCING if
the PNG datastream is embedded in
a MNG-1.0 datastream)
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
Any or all of interlace_type, compression_type, or
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
filter_method can be NULL if you are
not interested in their values.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
Note that png_get_IHDR() returns 32-bit data into
the application's width and height variables.
This is an unsafe situation if these are 16-bit
variables. In such situations, the
png_get_image_width() and png_get_image_height()
functions described below are safer.
width = png_get_image_width(png_ptr,
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
height = png_get_image_height(png_ptr,
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
bit_depth = png_get_bit_depth(png_ptr,
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
color_type = png_get_color_type(png_ptr,
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] In the manual, describe the png_get_IHDR() arguments in the right order.
2011-01-21 14:31:29 +00:00
interlace_type = png_get_interlace_type(png_ptr,
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
compression_type = png_get_compression_type(png_ptr,
info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] In the manual, describe the png_get_IHDR() arguments in the right order.
2011-01-21 14:31:29 +00:00
filter_method = png_get_filter_type(png_ptr,
[devel] Imported from libpng-1.4.0beta85.tar
2009-10-01 04:07:22 +00:00
info_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
channels = png_get_channels(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
channels - number of channels of info for the
color type (valid values are 1 (GRAY,
PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
4 (RGB_ALPHA or RGB + filler byte))
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
rowbytes = png_get_rowbytes(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
rowbytes - number of bytes needed to hold a row
signature = png_get_signature(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
signature - holds the signature read from the
file (if any). The data is kept in
the same offset it would be if the
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
whole signature were read (i.e. if an
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
application had already read in 4
bytes of signature before starting
libpng, the remaining 4 bytes would
be in signature[4] through signature[7]
(see png_set_sig_bytes())).
These are also important, but their validity depends on whether the chunk
has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
data has been read, or zero if it is missing. The parameters to the
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
png_get_<chunk> are set directly if they are simple data types, or a
pointer into the info_ptr is returned for any complex types.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
is simply returned to give the application information about how the
image was encoded. Libpng itself only does transformations using the file
gamma when combining semitransparent pixels with the background color, and,
since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
within the simplified API. Libpng also uses the file gamma when converting
RGB to gray, beginning with libpng-1.0.5, if the application calls
png_set_rgb_to_gray()).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_PLTE(png_ptr, info_ptr, &palette,
&num_palette);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
palette - the palette for the file
(array of png_color)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
num_palette - number of entries in the palette
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
png_get_gAMA(png_ptr, info_ptr, &file_gamma);
[devel] Trying a different PNG_UNUSED macro.
2011-01-27 15:37:34 +00:00
png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
file_gamma - the gamma at which the file is
written (PNG_INFO_gAMA)
int_file_gamma - 100,000 times the gamma at which the
file is written
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_get_cHRM(png_ptr, info_ptr, &white_x, &white_y, &red_x,
&red_y, &green_x, &green_y, &blue_x, &blue_y)
png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
&green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
&blue_Z)
png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
&int_white_y, &int_red_x, &int_red_y,
&int_green_x, &int_green_y, &int_blue_x,
&int_blue_y)
[devel] Describe the new XYZ APIs in the manual.
2011-08-25 22:48:18 +00:00
png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
&int_red_Z, &int_green_X, &int_green_Y,
&int_green_Z, &int_blue_X, &int_blue_Y,
&int_blue_Z)
[devel] Describe the new XYZ APIs in the manual.
2011-08-25 22:48:18 +00:00
{white,red,green,blue}_{x,y}
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
A color space encoding specified using the
chromaticities of the end points and the
white point. (PNG_INFO_cHRM)
[devel] Describe the new XYZ APIs in the manual.
2011-08-25 22:48:18 +00:00
{red,green,blue}_{X,Y,Z}
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
A color space encoding specified using the
encoding end points - the CIE tristimulus
specification of the intended color of the red,
green and blue channels in the PNG RGB data.
The white point is simply the sum of the three
end points. (PNG_INFO_cHRM)
[devel] Describe the new XYZ APIs in the manual.
2011-08-25 22:48:18 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Trying a different PNG_UNUSED macro.
2011-01-27 15:37:34 +00:00
file_srgb_intent - the rendering intent (PNG_INFO_sRGB)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The presence of the sRGB chunk
means that the pixel data is in the
sRGB color space. This chunk also
implies specific values of gAMA and
cHRM.
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_get_iCCP(png_ptr, info_ptr, &name,
&compression_type, &profile, &proflen);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
name - The profile name.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
compression_type - The compression type; always
PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
You may give NULL to this argument to
ignore it.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
profile - International Color Consortium color
profile data. May contain NULs.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
proflen - length of profile data in bytes.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
sig_bit - the number of significant bits for
(PNG_INFO_sBIT) each of the gray,
red, green, and blue channels,
whichever are appropriate for the
given color type (png_color_16)
[devel] Bumpt to version libpng-1.4.0beta74
2009-08-08 21:33:14 +00:00
png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
&num_trans, &trans_color);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Bumpt to version libpng-1.4.0beta74
2009-08-08 21:33:14 +00:00
trans_alpha - array of alpha (transparency)
entries for palette (PNG_INFO_tRNS)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set|get_tRNS().
2011-01-15 16:25:25 +00:00
num_trans - number of transparent entries
(PNG_INFO_tRNS)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta35.tar
2008-10-06 15:16:17 +00:00
trans_color - graylevel or color sample values of
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
the single transparent color for
non-paletted images (PNG_INFO_tRNS)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_hIST(png_ptr, info_ptr, &hist);
(PNG_INFO_hIST)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
hist - histogram of palette (array of
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
png_uint_16)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_tIME(png_ptr, info_ptr, &mod_time);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
mod_time - time image was last modified
(PNG_VALID_tIME)
png_get_bKGD(png_ptr, info_ptr, &background);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
background - background color (of type
png_color_16p) (PNG_VALID_bKGD)
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
valid 16-bit red, green and blue
values, regardless of color_type
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
num_comments = png_get_text(png_ptr, info_ptr,
&text_ptr, &num_text);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
num_comments - number of comments
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
text_ptr - array of png_text holding image
comments
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].compression - type of compression used
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
on "text" PNG_TEXT_COMPRESSION_NONE
PNG_TEXT_COMPRESSION_zTXt
PNG_ITXT_COMPRESSION_NONE
PNG_ITXT_COMPRESSION_zTXt
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].key - keyword for comment. Must contain
1-79 characters.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].text - text comments for current
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
keyword. Can be empty.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].text_length - length of text string,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
after decompression, 0 for iTXt
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].itxt_length - length of itxt string,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
after decompression, 0 for tEXt/zTXt
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].lang - language of comment (empty
string for unknown).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.2.2beta5.tar
2002-03-26 00:49:08 +00:00
text_ptr[i].lang_key - keyword in UTF-8
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
(empty string for unknown).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.4.0beta89.tar
2009-11-01 02:31:08 +00:00
Note that the itxt_length, lang, and lang_key
[libpng15] Updated the documentation of the png_text structure (clarifying that the "lang" and "lang_key" fields can be NULL pointers or might not exist).
2011-11-21 23:05:41 +00:00
members of the text_ptr structure only exist when the
library is built with iTXt chunk support. Prior to
libpng-1.4.0 the library was built by default without
iTXt support. Also note that when iTXt is supported,
they contain NULL pointers when the "compression"
field contains PNG_TEXT_COMPRESSION_NONE or
PNG_TEXT_COMPRESSION_zTXt.
[devel] Imported from libpng-1.4.0beta89.tar
2009-11-01 02:31:08 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
num_text - number of comments (same as
num_comments; you can put NULL here
to avoid the duplication)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
Note while png_set_text() will accept text, language,
and translated keywords that can be NULL pointers, the
structure returned by png_get_text will always contain
regular zero-terminated C strings. They might be
empty strings but they will never be NULL pointers.
num_spalettes = png_get_sPLT(png_ptr, info_ptr,
&palette_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
num_spalettes - number of sPLT chunks read.
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
palette_ptr - array of palette structures holding
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
contents of one or more sPLT chunks
read.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
&unit_type);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
offset_x - positive offset from the left edge
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
of the screen (can be negative)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
offset_y - positive offset from the top edge
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
of the screen (can be negative)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
&unit_type);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
res_x - pixels/unit physical resolution in
x direction
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
res_y - pixels/unit physical resolution in
x direction
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
unit_type - PNG_RESOLUTION_UNKNOWN,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG_RESOLUTION_METER
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_get_sCAL(png_ptr, info_ptr, &unit, &width,
&height)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unit - physical scale units (an integer)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
width - width of a pixel in physical scale units
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
height - height of a pixel in physical scale units
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
(width and height are doubles)
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
&height)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unit - physical scale units (an integer)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
width - width of a pixel in physical scale units
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
(expressed as a string)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
height - height of a pixel in physical scale units
(width and height are strings like "2.54")
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
num_unknown_chunks = png_get_unknown_chunks(png_ptr,
info_ptr, &unknowns)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
unknowns - array of png_unknown_chunk
structures holding unknown chunks
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
unknowns[i].name - name of unknown chunk
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
unknowns[i].data - data of unknown chunk
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unknowns[i].size - size of unknown chunk's data
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
unknowns[i].location - position of chunk in file
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
The value of "i" corresponds to the order in which the
chunks were read from the PNG file or inserted with the
png_set_unknown_chunks() function.
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
The value of "location" is a bitwise "or" of
PNG_HAVE_IHDR (0x01)
PNG_HAVE_PLTE (0x02)
PNG_AFTER_IDAT (0x08)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The data from the pHYs chunk can be retrieved in several convenient
forms:
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
res_x = png_get_x_pixels_per_meter(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
res_y = png_get_y_pixels_per_meter(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
res_x_and_y = png_get_pixels_per_meter(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
res_x = png_get_x_pixels_per_inch(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
res_y = png_get_y_pixels_per_inch(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
res_x_and_y = png_get_pixels_per_inch(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
info_ptr)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Each of these returns 0 [signifying "unknown"] if
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
the data is not present or if res_x is 0;
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
res_x_and_y is 0 if res_x != res_y
Note that because of the way the resolutions are
stored internally, the inch conversions won't
come out to exactly even number. For example,
72 dpi is stored as 0.28346 pixels/meter, and
when this is retrieved it is 71.9988 dpi, so
be sure to round the returned value appropriately
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
if you want to display a reasonable-looking result.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
The data from the oFFs chunk can be retrieved in several convenient
forms:
x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Each of these returns 0 [signifying "unknown" if both
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
x and y are 0] if the data is not present or if the
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
chunk is present but the unit is the pixel. The
remark about inexact inch conversions applies here
as well, because a value in inches can't always be
converted to microns and back without some loss
of precision.
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
For more information, see the
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG specification for chunk contents. Be careful with trusting
rowbytes, as some of the transformations could increase the space
needed to hold a row (expand, filler, gray_to_rgb, etc.).
See png_read_update_info(), below.
A quick word about text_ptr and num_text. PNG stores comments in
keyword/text pairs, one pair per chunk, with no limit on the number
of text chunks, and a 2^31 byte limit on their size. While there are
suggested keywords, there is no requirement to restrict the use to these
strings. It is strongly suggested that keywords and text be sensible
to humans (that's the point), so don't use abbreviations. Non-printing
symbols are not allowed. See the PNG specification for more details.
There is also no requirement to have text after the keyword.
Keywords should be limited to 79 Latin-1 characters without leading or
trailing spaces, but non-consecutive spaces are allowed within the
keyword. It is possible to have the same keyword any number of times.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
The text_ptr is an array of png_text structures, each holding a
pointer to a language string, a pointer to a keyword and a pointer to
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
a text string. The text string, language code, and translated
keyword may be empty or NULL pointers. The keyword/text
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
pairs are put into the array in the order that they are received.
However, some or all of the text chunks may be after the image, so, to
make sure you have read all the text chunks, don't mess with these
until after you read the stuff after the image. This will be
mentioned again below in the discussion that goes with png_read_end().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Input transformations
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you've read the header information, you can set up the library
to handle any special transformations of the image data. The various
ways to transform the data will be described in the order that they
should occur. This is important, as some of these change the color
type and/or bit depth of the data, and some others only work on
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
certain color types and bit depths.
Transformations you request are ignored if they don't have any meaning for a
particular input data format. However some transformations can have an effect
as a result of a previous transformation. If you specify a contradictory set of
transformations, for example both adding and removing the alpha channel, you
cannot predict the final result.
The color used for the transparency values should be supplied in the same
format/depth as the current image data. It is stored in the same format/depth
as the image data in a tRNS chunk, so this is what libpng expects for this data.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
The color used for the background value depends on the need_expand argument as
described below.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Data will be decoded into the supplied row buffers packed into bytes
unless the library has been told to transform it into another format.
For example, 4 bit/pixel paletted or grayscale data will be returned
2 pixels/byte with the leftmost pixel in the high-order bits of the
byte, unless png_set_packing() is called. 8-bit RGB data will be stored
Imported from libpng-1.2.7rc1.tar
2004-09-04 18:25:08 +00:00
in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
is called to insert filler bytes, either before or after each RGB triplet.
16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
byte of the color value first, unless png_set_scale_16() is called to
Imported from libpng-1.2.8beta1.tar
2004-11-01 20:13:40 +00:00
transform it to regular RGB RGB triplets, or png_set_filler() or
png_set_add alpha() is called to insert filler bytes, either before or
after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
or png_set_scale_16().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The following code transforms grayscale images of less than 8 to 8 bits,
changes paletted images to RGB, and adds a full alpha channel if there is
transparency information in a tRNS chunk. This is most useful on
grayscale images with bit depths of 2 or 4 or if there is a multiple-image
viewing application that wishes to treat all images in the same way.
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (png_get_valid(png_ptr, info_ptr,
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
if (color_type == PNG_COLOR_TYPE_GRAY &&
bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
The first two functions are actually aliases for png_set_expand(), added
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
in libpng version 1.0.4, with the function names expanded to improve code
readability. In some future version they may actually do different
things.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.9beta8.tar
2006-03-09 05:35:59 +00:00
As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
added. It expands the sample depth without changing tRNS to alpha.
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
As of libpng version 1.5.2, png_set_expand_16() was added. It behaves as
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
png_set_expand(); however, the resultant channels have 16 bits rather than 8.
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
Use this when the output color or gray channels are made linear to avoid fairly
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
severe accuracy loss.
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
if (bit_depth < 16)
png_set_expand_16(png_ptr);
Imported from libpng-1.2.9beta8.tar
2006-03-09 05:35:59 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG can have files with 16 bits per channel. If you only can handle
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
8 bits per channel, this will strip the pixels down to 8-bit.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (bit_depth == 16)
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
#if PNG_LIBPNG_VER >= 10504
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
png_set_scale_16(png_ptr);
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
#else
png_set_strip_16(png_ptr);
#endif
(The more accurate "png_set_scale_16()" API became available in libpng version
1.5.4).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
If you need to process the alpha channel on the image separately from the image
data (for example if you convert it to a bitmap mask) it is possible to have
libpng strip the channel leaving just RGB or gray data:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (color_type & PNG_COLOR_MASK_ALPHA)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_strip_alpha(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
If you strip the alpha channel you need to find some other way of dealing with
the information. If, instead, you want to convert the image to an opaque
version with no alpha channel use png_set_background; see below.
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
As of libpng version 1.5.2, almost all useful expansions are supported, the
[devel] Fix spelling of "conversion" in manual.
2011-05-17 11:56:50 +00:00
major ommissions are conversion of grayscale to indexed images (which can be
done trivially in the application) and conversion of indexed to grayscale (which
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
can be done by a trivial manipulation of the palette.)
In the following table, the 01 means grayscale with depth<8, 31 means
indexed with depth<8, other numerals represent the color type, "T" means
the tRNS chunk is present, A means an alpha channel is present, and O
means tRNS or alpha is present but all pixels in the image are opaque.
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
TO
01 - [G] - - - - - - - - - - - - -
31 [Q] Q [Q] [Q] [Q] Q Q Q Q Q Q [Q] [Q] Q Q
0 1 G + . . G G G G G G B B GB GB
0T lt Gt t + . Gt G G Gt G G Bt Bt GBt GBt
0O lt Gt t . + Gt Gt G Gt Gt G Bt Bt GBt GBt
2 C P C C C + . . C - - CB CB B B
2T Ct - Ct C C t + t - - - CBt CBt Bt Bt
2O Ct - Ct C C t t + - - - CBt CBt Bt Bt
3 [Q] p [Q] [Q] [Q] Q Q Q + . . [Q] [Q] Q Q
3T [Qt] p [Qt][Q] [Q] Qt Qt Qt t + t [Qt][Qt] Qt Qt
3O [Qt] p [Qt][Q] [Q] Qt Qt Qt t t + [Qt][Qt] Qt Qt
4A lA G A T T GA GT GT GA GT GT + BA G GBA
4O lA GBA A T T GA GT GT GA GT GT BA + GBA G
6A CA PA CA C C A T tT PA P P C CBA + BA
6O CA PBA CA C C A tT T PA P P CBA C BA +
Within the matrix,
"+" identifies entries where 'from' and 'to' are the same.
"-" means the transformation is not supported.
"." means nothing is necessary (a tRNS chunk can just be ignored).
"t" means the transformation is obtained by png_set_tRNS.
"A" means the transformation is obtained by png_set_add_alpha().
"X" means the transformation is obtained by png_set_expand().
"1" means the transformation is obtained by
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
if there is no transparency in the original or the final
format).
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
"C" means the transformation is obtained by png_set_gray_to_rgb().
[devel] Removed reference to non-existent png_set_rgb_to_Y from the manual.
2011-05-16 14:08:51 +00:00
"G" means the transformation is obtained by png_set_rgb_to_gray().
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
"P" means the transformation is obtained by
png_set_expand_palette_to_rgb().
"p" means the transformation is obtained by png_set_packing().
"Q" means the transformation is obtained by png_set_quantize().
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
"T" means the transformation is obtained by
png_set_tRNS_to_alpha().
"B" means the transformation is obtained by
png_set_background(), or png_strip_alpha().
[devel] Document png_set_expand_16, correct transformation table.
2011-02-12 15:03:44 +00:00
When an entry has multiple transforms listed all are required to cause the
right overall transformation. When two transforms are separated by a comma
either will do the job. When transforms are enclosed in [] the transform should
do the job but this is currently unimplemented - a different format will result
if the suggested transformations are used.
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
In PNG files, the alpha channel in an image
is the level of opacity. If you need the alpha channel in an image to
be the level of transparency instead of opacity, you can invert the
alpha channel (or the tRNS chunk data) after it's read, so that 0 is
fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
images) is fully transparent, with
png_set_invert_alpha(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
they can, resulting in, for example, 8 pixels per byte for 1 bit
files. This code expands to 1 pixel per byte without changing the
values of the pixels:
if (bit_depth < 8)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_packing(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels
stored in a PNG image have been "scaled" or "shifted" up to the next
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
to 8 bits/sample in the range [0, 255]). However, it is also possible
to convert the PNG pixel data back to the original bit depth of the
image. This call reduces the pixels back down to the original bit depth:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.0beta5.tar
2001-08-08 03:25:59 +00:00
png_color_8p sig_bit;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_shift(png_ptr, sig_bit);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG files store 3-color pixels in red, green, blue order. This code
changes the storage of the pixels to blue, green, red:
if (color_type == PNG_COLOR_TYPE_RGB ||
color_type == PNG_COLOR_TYPE_RGB_ALPHA)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_bgr(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.0rc1.tar
2001-08-25 11:46:06 +00:00
PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
into 4 or 8 bytes for windowing systems that need them in this format:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.0rc1.tar
2001-08-25 11:46:06 +00:00
if (color_type == PNG_COLOR_TYPE_RGB)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.1a.tar
1998-04-21 20:03:57 +00:00
where "filler" is the 8 or 16-bit number to fill with, and the location is
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
you want the filler before the RGB or after. This transformation
Imported from libpng-1.2.0rc1.tar
2001-08-25 11:46:06 +00:00
does not affect images that already have full alpha channels. To add an
opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
will generate RGBA pixels.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.7rc1.tar
2004-09-04 18:25:08 +00:00
Note that png_set_filler() does not change the color type. If you want
to do that, you can add a true alpha channel with
if (color_type == PNG_COLOR_TYPE_RGB ||
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
color_type == PNG_COLOR_TYPE_GRAY)
png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
Imported from libpng-1.2.7rc1.tar
2004-09-04 18:25:08 +00:00
where "filler" contains the alpha value to assign to each pixel.
Imported from libpng-1.2.8beta1.tar
2004-11-01 20:13:40 +00:00
This function was added in libpng-1.2.7.
Imported from libpng-1.2.7rc1.tar
2004-09-04 18:25:08 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you are reading an image with an alpha channel, and you need the
data as ARGB instead of the normal PNG format RGBA:
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_swap_alpha(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
For some uses, you may want a grayscale image to be represented as
RGB. This code will do that conversion:
if (color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_gray_to_rgb(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
with alpha.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
if (color_type == PNG_COLOR_TYPE_RGB ||
color_type == PNG_COLOR_TYPE_RGB_ALPHA)
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_set_rgb_to_gray(png_ptr, error_action,
double red_weight, double green_weight);
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
error_action = 1: silently do the conversion
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
error_action = 2: issue a warning if the original
image has any pixel where
red != green or red != blue
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
error_action = 3: issue an error and abort the
conversion if the original
image has any pixel where
red != green or red != blue
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
red_weight: weight of red component
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
green_weight: weight of green component
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
If either weight is negative, default
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
weights are used.
In the corresponding fixed point API the red_weight and green_weight values are
simply scaled by 100,000:
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_set_rgb_to_gray(png_ptr, error_action,
png_fixed_point red_weight,
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
png_fixed_point green_weight);
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
If you have set error_action = 1 or 2, you can
later check whether the image really was gray, after processing
the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
It will return a png_byte that is zero if the image was gray or
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
1 if there were any non-gray pixels. Background and sBIT data
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
will be silently converted to grayscale, using the green channel
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
data for sBIT, regardless of the error_action setting.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
The default values come from the PNG file cHRM chunk if present; otherwise, the
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
defaults correspond to the ITU-R recommendation 709, and also the sRGB color
space, as recommended in the Charles Poynton's Colour FAQ,
<http://www.poynton.com/>, in section 9:
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Updated commentary about the png_rgb_to_gray() default coefficients
2011-07-29 17:31:16 +00:00
Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
Previous versions of this document, 1998 through 2002, recommended a slightly
different formula:
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
[devel] Updated commentary about the png_rgb_to_gray() default coefficients
2011-07-29 17:31:16 +00:00
Libpng uses an integer approximation:
Y = (6968 * R + 23434 * G + 2366 * B)/32768
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
The calculation is done in a linear colorspace, if the image gamma
[devel] Imported from libpng-1.5.1beta09.tar
2011-01-24 06:12:14 +00:00
can be determined.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
The png_set_background() function has been described already; it tells libpng to
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
composite images with alpha or simple transparency against the supplied
background color. For compatibility with versions of libpng earlier than
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
libpng-1.5.4 it is recommended that you call the function after reading the file
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
header, even if you don't want to use the color in a bKGD chunk, if one exists.
If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
you may use this color, or supply another color more suitable for
the current display (e.g., the background color from a web page). You
need to tell libpng how the color is represented, both the format of the
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
component values in the color (the number of bits) and the gamma encoding of the
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
color. The function takes two arguments, background_gamma_mode and need_expand
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
to convey this information; however, only two combinations are likely to be
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
useful:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Reverted type of "my_background" to png_color_16 in the manual.
2011-07-10 11:55:14 +00:00
png_color_16 my_background;
png_color_16p image_background;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
if (png_get_bKGD(png_ptr, info_ptr, &image_background))
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_background(png_ptr, image_background,
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
else
[devel] Reverted type of "my_background" to png_color_16 in the manual.
2011-07-10 11:55:14 +00:00
png_set_background(png_ptr, &my_background,
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
The second call was described above - my_background is in the format of the
final, display, output produced by libpng. Because you now know the format of
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
output and to retain palette images (the palette colors will be modified
appropriately and the tRNS chunk removed.) However, if you are doing this,
take great care not to ask for transformations without checking first that
they apply!
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
In the first call the background color has the original bit depth and color type
of the PNG file. So, for palette images the color is supplied as a palette
index and for low bit greyscale images the color is a reduced bit value in
image_background->gray.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
If you didn't call png_set_gamma() before reading the file header, for example
if you need your code to remain compatible with older versions of libpng prior
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
to libpng-1.5.4, this is the place to call it.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Documented png_set_alpha_mode(), other changes in libpng.3 and libpng-manual.txt. The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative parameters are supplied by the caller), while in the absence of cHRM sRGB/Rec 709 values are still used. The bKGD chunk no longer overwrites the background value set by png_set_background(), allowing the latter to be used before the file header is read. It never performed any useful function to override the default anyway. Send comments/corrections/commendations to png-mng-implement at lists.sf.net: (subscription required; visit
2011-05-13 02:48:29 +00:00
Do not call it if you called png_set_alpha_mode(); doing so will damage the
settings put in place by png_set_alpha_mode(). (If png_set_alpha_mode() is
supported then you can certainly do png_set_gamma() before reading the PNG
header.)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Fix typos in comments, add new API synopses to libpng.3
2011-05-08 02:23:43 +00:00
This API unconditionally sets the screen and file gamma values, so it will
override the value in the PNG file unless it is called before the PNG file
reading starts. For this reason you must always call it with the PNG file
value when you call it in this position:
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
png_set_gamma(png_ptr, screen_gamma, file_gamma);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
else
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
png_set_gamma(png_ptr, screen_gamma, 0.45455);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
If you need to reduce an RGB file to a paletted file, or if a paletted
file has more entries then will fit on your screen, png_set_quantize()
[devel] Freeze build-time only configuration in the build. In all prior versions of libpng most configuration options controlled by compiler #defines had to be repeated by the application code that used libpng. This patch changes this so that compilation options that can only be changed at build time are frozen in the build. Options that are compiler dependent (and those that are system dependent) are evaluated each time - pngconf.h holds these. Options that can be changed per-file in the application are in png.h. Frozen options are in the new installed header file pnglconf.h
2010-04-17 03:12:51 +00:00
will do that. Note that this is a simple match quantization that merely
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
finds the closest color available. This should work fairly well with
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
optimized palettes, but fairly badly with linear color cubes. If you
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
pass a palette that is larger than maximum_colors, the file will
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
reduce the number of colors in the palette so it will fit into
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
maximum_colors. If there is a histogram, libpng will use it to make
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
more intelligent choices when reducing the palette. If there is no
histogram, it may not do as good a job.
if (color_type & PNG_COLOR_MASK_COLOR)
{
if (png_get_valid(png_ptr, info_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
PNG_INFO_PLTE))
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
{
png_uint_16p histogram = NULL;
png_get_hIST(png_ptr, info_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
&histogram);
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
png_set_quantize(png_ptr, palette, num_palette,
max_screen_colors, histogram, 1);
}
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
else
{
png_color std_color_cube[MAX_SCREEN_COLORS] =
{ ... colors ... };
png_set_quantize(png_ptr, std_color_cube,
MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
NULL,0);
}
}
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG files describe monochrome as black being zero and white being one.
The following code will reverse this (make black be one and white be
zero):
Imported from libpng-1.2.0beta5.tar
2001-08-08 03:25:59 +00:00
if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
png_set_invert_mono(png_ptr);
This function can also be used to invert grayscale and gray-alpha images:
if (color_type == PNG_COLOR_TYPE_GRAY ||
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_invert_mono(png_ptr);
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
PNG files store 16-bit pixels in network byte order (big-endian,
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
ie. most significant bits first). This code changes the storage to the
other way (little-endian, i.e. least significant bits first, the
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
way PCs store them):
if (bit_depth == 16)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_set_swap(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
need to change the order the pixels are packed into bytes, you can use:
if (bit_depth < 8)
png_set_packswap(png_ptr);
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
Finally, you can write your own transformation function if none of
the existing ones meets your needs. This is done by setting a callback
with
png_set_read_user_transform_fn(png_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
read_transform_fn);
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
You must supply the function
[devel] Fixed mistake in the descriptions of user read_transform and write_transform function prototypes in the manual. The row_info struct should be of type png_row_infop.
2011-02-14 01:42:19 +00:00
void read_transform_fn(png_structp png_ptr, png_row_infop
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
row_info, png_bytep data)
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
See pngtest.c for a working example. Your function will be called
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
after all of the other transformations have been processed. Take care with
interlaced images if you do the interlace yourself - the width of the row is the
width in 'row_info', not the overall image width.
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
If supported, libpng provides two information routines that you can use to find
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
where you are in processing the image:
png_get_current_pass_number(png_structp png_ptr);
png_get_current_row_number(png_structp png_ptr);
Don't try using these outside a transform callback - firstly they are only
supported if user transforms are supported, secondly they may well return
unexpected results unless the row is actually being processed at the moment they
are called.
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
[devel] Correct png_get_current_row_number documentation
2011-02-16 12:15:13 +00:00
With interlaced
images the value returned is the row in the input sub-image image. Use
PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
The discussion of interlace handling above contains more information on how to
use these values.
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
You can also set up a pointer to a user structure for use by your
callback function, and you can inform libpng that your transform
function will change the number of channels or bit depth with the
function
png_set_user_transform_info(png_ptr, user_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
user_depth, user_channels);
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
The user's application, not libpng, is responsible for allocating and
freeing any memory required for the user structure.
You can retrieve the pointer via the function
png_get_user_transform_ptr(). For example:
voidp read_user_transform_ptr =
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_get_user_transform_ptr(png_ptr);
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The last thing to handle is interlacing; this is covered in detail below,
but you must call the function here if you want libpng to handle expansion
of the interlaced image.
number_of_passes = png_set_interlace_handling(png_ptr);
After setting the transformations, libpng can update your png_info
structure to reflect any transformations you've requested with this
[libpng15] Added a note in the manual the png_read_update_info() must be called only once with a particular info_ptr.
2011-09-26 21:35:22 +00:00
call.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_read_update_info(png_ptr, info_ptr);
[libpng15] Added a note in the manual the png_read_update_info() must be called only once with a particular info_ptr.
2011-09-26 21:35:22 +00:00
This is most useful to update the info structure's rowbytes
field so you can use it to allocate your image memory. This function
will also update your palette with the correct screen_gamma and
background if these have been given with the calls above. You may
only call png_read_update_info() once with a particular info_ptr.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you call png_read_update_info(), you can allocate any
memory you need to hold the image. The row data is simply
raw byte data for all forms of images. As the actual allocation
varies among applications, no example will be given. If you
are allocating one large chunk, you will need to build an
array of pointers to each row, as it will be needed for some
of the functions below.
[libpng15] Added a note in the manual the png_read_update_info() must be called only once with a particular info_ptr.
2011-09-26 21:35:22 +00:00
Remember: Before you call png_read_update_info(), the png_get_*()
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
functions return the values corresponding to the original PNG image.
After you call png_read_update_info the values refer to the image
that libpng will output. Consequently you must call all the png_set_
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
functions before you call png_read_update_info(). This is particularly
important for png_set_interlace_handling() - if you are going to call
png_read_update_info() you must call png_set_interlace_handling() before
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
it unless you want to receive interlaced output.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Reading image data
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you've allocated memory, you can read the image data.
The simplest way to do this is in one function call. If you are
allocating enough memory to hold the whole image, you can just
call png_read_image() and libpng will read in all the image data
and put it in the memory area supplied. You will need to pass in
an array of pointers to each row.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
This function automatically handles interlacing, so you don't
need to call png_set_interlace_handling() (unless you call
png_read_update_info()) or call this function multiple times, or any
of that other stuff necessary with png_read_rows().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_read_image(png_ptr, row_pointers);
where row_pointers is:
png_bytep row_pointers[height];
You can point to void or char or whatever you use for pixels.
If you don't want to read in the whole image at once, you can
use png_read_rows() instead. If there is no interlacing (check
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
interlace_type == PNG_INTERLACE_NONE), this is simple:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_read_rows(png_ptr, row_pointers, NULL,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
number_of_rows);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
where row_pointers is the same as in the png_read_image() call.
If you are doing this just one row at a time, you can do this with
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
a single row_pointer instead of an array of row_pointers:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
png_bytep row_pointer = row;
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
png_read_row(png_ptr, row_pointer, NULL);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
get somewhat harder. The only current (PNG Specification version 1.2)
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
a somewhat complicated 2D interlace scheme, known as Adam7, that
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
breaks down an image into seven smaller images of varying size, based
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
on an 8x8 grid. This number is defined (from libpng 1.5) as
PNG_INTERLACE_ADAM7_PASSES in png.h
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
libpng can fill out those images or it can give them to you "as is".
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
It is almost always better to have libpng handle the interlacing for you.
If you want the images filled out, there are two ways to do that. The one
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
mentioned in the PNG specification is to expand each pixel to cover
those pixels that have not been read yet (the "rectangle" method).
This results in a blocky image for the first pass, which gradually
smooths out as more pixels are read. The other method is the "sparkle"
method, where pixels are drawn only in their final locations, with the
rest of the image remaining whatever colors they were initialized to
before the start of the read. The first method usually looks better,
but tends to be slower, as there are more pixels to put in the rows.
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
If, as is likely, you want libpng to expand the images, call this before
calling png_start_read_image() or png_read_update_info():
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
if (interlace_type == PNG_INTERLACE_ADAM7)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
number_of_passes
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
= png_set_interlace_handling(png_ptr);
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
This will return the number of passes needed. Currently, this is seven,
but may change if another interlace type is added. This function can be
called even if the file is not interlaced, where it will return one pass.
You then need to read the whole image 'number_of_passes' times. Each time
will distribute the pixels from the current pass to the correct place in
the output image, so you need to supply the same rows to png_read_rows in
each pass.
[devel] Update documentation
2010-07-30 00:09:18 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you are not going to display the image after each pass, but are
going to wait until the entire image is read in, use the sparkle
effect. This effect is faster and the end result of either method
is exactly the same. If you are planning on displaying the image
after each pass, the "rectangle" effect is generally considered the
better looking one.
If you only want the "sparkle" effect, just call png_read_rows() as
normal, with the third parameter NULL. Make sure you make pass over
the image number_of_passes times, and you don't change the data in the
rows between calls. You can change the locations of the data, just
not the data. Each pass only writes the pixels appropriate for that
pass, and assumes the data from previous passes is still valid.
png_read_rows(png_ptr, row_pointers, NULL,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
number_of_rows);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you only want the first effect (the rectangles), do the same as
before except pass the row buffer in the third parameter, and leave
the second parameter NULL.
png_read_rows(png_ptr, NULL, row_pointers,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
number_of_rows);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
If you don't want libpng to handle the interlacing details, just call
png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Each of the images is a valid image by itself; however, you will almost
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
certainly need to distribute the pixels from each sub-image to the
correct place. This is where everything gets very tricky.
If you want to retrieve the separate images you must pass the correct
number of rows to each successive call of png_read_rows(). The calculation
gets pretty complicated for small images, where some sub-images may
not even exist because either their width or height ends up zero.
libpng provides two macros to help you in 1.5 and later versions:
png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
Respectively these tell you the width and height of the sub-image
corresponding to the numbered pass. 'pass' is in in the range 0 to 6 -
this can be confusing because the specification refers to the same passes
as 1 to 7! Be careful, you must check both the width and height before
calling png_read_rows() and not call it for that pass if either is zero.
You can, of course, read each sub-image row by row. If you want to
produce optimal code to make a pixel-by-pixel transformation of an
interlaced image this is the best approach; read each row of each pass,
transform it, and write it out to a new interlaced image.
If you want to de-interlace the image yourself libpng provides further
macros to help that tell you where to place the pixels in the output image.
Because the interlacing scheme is rectangular - sub-image pixels are always
arranged on a rectangular grid - all you need to know for each pass is the
starting column and row in the output image of the first pixel plus the
spacing between each pixel. As of libpng 1.5 there are four macros to
retrieve this information:
png_uint_32 x = PNG_PASS_START_COL(pass);
png_uint_32 y = PNG_PASS_START_ROW(pass);
png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
These allow you to write the obvious loop:
png_uint_32 input_y = 0;
png_uint_32 output_y = PNG_PASS_START_ROW(pass);
while (output_y < output_image_height)
{
png_uint_32 input_x = 0;
png_uint_32 output_x = PNG_PASS_START_COL(pass);
while (output_x < output_image_width)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
image[output_y][output_x] =
subimage[pass][input_y][input_x++];
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
output_x += xStep;
}
++input_y;
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
output_y += yStep;
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
}
Notice that the steps between successive output rows and columns are
returned as shifts. This is possible because the pixels in the subimages
are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
image. In practice you may need to directly calculate the output coordinate
given an input coordinate. libpng provides two further macros for this
purpose:
png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
Finally a pair of macros are provided to tell you if a particular image
row or column appears in a given pass:
int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
Bear in mind that you will probably also need to check the width and height
of the pass in addition to the above to be sure the pass even exists!
With any luck you are convinced by now that you don't want to do your own
interlace handling. In reality normally the only good reason for doing this
is if you are processing PNG files on a pixel-by-pixel basis and don't want
to load the whole file into memory when it is interlaced.
libpng includes a test program, pngvalid, that illustrates reading and
writing of interlaced images. If you can't get interlacing to work in your
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
code and don't want to leave it to libpng (the recommended approach), see
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
how pngvalid.c does it.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Finishing a sequential read
Imported from libpng-1.2.9beta1.tar
2006-02-21 04:09:05 +00:00
After you are finished reading the image through the
low-level interface, you can finish reading the file. If you are
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
interested in comments or time, which may be stored either before or
after the image data, you should pass the separate png_info struct if
you want to keep the comments from before and after the image
[devel] Added more about creating and destroying the optional "end_info" structure in the libpng documentation.
2011-04-21 03:20:40 +00:00
separate.
png_infop end_info = png_create_info_struct(png_ptr);
if (!end_info)
{
png_destroy_read_struct(&png_ptr, &info_ptr,
(png_infopp)NULL);
return (ERROR);
}
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_read_end(png_ptr, end_info);
[devel] Added more about creating and destroying the optional "end_info" structure in the libpng documentation.
2011-04-21 03:20:40 +00:00
If you are not interested, you should still call png_read_end()
but you can pass NULL, avoiding the need to create an end_info structure.
png_read_end(png_ptr, (png_infop)NULL);
[devel] Mention the reason to call png_read_end() in the libpng documentation.
2011-04-20 22:43:52 +00:00
If you don't call png_read_end(), then your file pointer will be
left pointing to the first chunk after the last IDAT, which is probably
not what you want if you expect to read something beyond the end of
the PNG datastream.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
When you are done, you can free all memory allocated by libpng like this:
png_destroy_read_struct(&png_ptr, &info_ptr,
&end_info);
[devel] Added more about creating and destroying the optional "end_info" structure in the libpng documentation.
2011-04-21 03:20:40 +00:00
or, if you didn't create an end_info structure,
png_destroy_read_struct(&png_ptr, &info_ptr,
(png_infopp)NULL);
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
It is also possible to individually free the info_ptr members that
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
point to libpng-allocated storage with the following function:
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_free_data(png_ptr, info_ptr, mask, seq)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
mask - identifies data to be freed, a mask
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
containing the bitwise OR of one or
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
more of
PNG_FREE_PLTE, PNG_FREE_TRNS,
PNG_FREE_HIST, PNG_FREE_ICCP,
PNG_FREE_PCAL, PNG_FREE_ROWS,
PNG_FREE_SCAL, PNG_FREE_SPLT,
PNG_FREE_TEXT, PNG_FREE_UNKN,
or simply PNG_FREE_ALL
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
seq - sequence number of item to be freed
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
(-1 for all items)
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
This function may be safely called when the relevant storage has
Imported from libpng-1.0.6a.tar
2000-04-02 03:10:05 +00:00
already been freed, or has not yet been allocated, or was allocated
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
by the user and not by libpng, and will in those cases do nothing.
The "seq" parameter is ignored if only one item of the selected data
type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
are allowed for the data type identified in the mask, such as text or
sPLT, only the n'th item in the structure is freed, where n is "seq".
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
The default behavior is only to free data that was allocated internally
by libpng. This can be changed, so that libpng will not free the data,
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
or so that it will free data that was allocated by the user with png_malloc()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
or png_calloc() and passed in via a png_set_*() function, with
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
png_data_freer(png_ptr, info_ptr, freer, mask)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
freer - one of
PNG_DESTROY_WILL_FREE_DATA
PNG_SET_WILL_FREE_DATA
PNG_USER_WILL_FREE_DATA
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
mask - which data elements are affected
same choices as in png_free_data()
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
This function only affects data that has already been allocated.
You can call this function after reading the PNG data but before calling
any png_set_*() functions, to control whether the user or the png_set_*()
function is responsible for freeing any existing data that might be present,
and again after the png_set_*() functions to control whether the user
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
or png_destroy_*() is supposed to free the data. When the user assumes
responsibility for libpng-allocated data, the application must use
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
png_free() to free it, and when the user transfers responsibility to libpng
for data that the user has allocated, the user must have used png_malloc()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
or png_calloc() to allocate it.
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
If you allocated your row_pointers in a single block, as suggested above in
the description of the high level read interface, you must not transfer
responsibility for freeing it to the png_set_rows or png_read_destroy function,
because they would also try to free the individual row_pointers[i].
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
separately, do not transfer responsibility for freeing text_ptr to libpng,
because when libpng fills a png_text structure it combines these members with
the key member, and png_free_data() will free only text_ptr.key. Similarly,
if you transfer responsibility for free'ing text_ptr from libpng to your
application, your application must not separately free those members.
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
The png_free_data() function will turn off the "valid" flag for anything
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
it frees. If you need to turn the flag off for a chunk that was freed by
your application instead of by libpng, you can use
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
png_set_invalid(png_ptr, info_ptr, mask);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
mask - identifies the chunks to be made invalid,
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
containing the bitwise OR of one or
Imported from libpng-1.0.9beta3.tar
2000-11-23 17:51:42 +00:00
more of
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
PNG_INFO_gAMA, PNG_INFO_sBIT,
PNG_INFO_cHRM, PNG_INFO_PLTE,
PNG_INFO_tRNS, PNG_INFO_bKGD,
PNG_INFO_hIST, PNG_INFO_pHYs,
PNG_INFO_oFFs, PNG_INFO_tIME,
PNG_INFO_pCAL, PNG_INFO_sRGB,
PNG_INFO_iCCP, PNG_INFO_sPLT,
PNG_INFO_sCAL, PNG_INFO_IDAT
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
For a more compact example of reading a PNG image, see the file example.c.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Reading PNG files progressively
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The progressive reader is slightly different then the non-progressive
reader. Instead of calling png_read_info(), png_read_rows(), and
png_read_end(), you make one call to png_process_data(), which calls
callbacks when it has the info, a row, or the end of the image. You
set up these callbacks with png_set_progressive_read_fn(). You don't
have to worry about the input/output functions of libpng, as you are
giving the library the data directly in png_process_data(). I will
assume that you have read the section on reading PNG files above,
so I will only highlight the differences (although I will show
all of the code).
png_structp png_ptr;
png_infop info_ptr;
/* An example code fragment of how you would
initialize the progressive reader in your
application. */
int
initialize_png_reader()
{
png_ptr = png_create_read_struct
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
(PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
user_error_fn, user_warning_fn);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!png_ptr)
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
return (ERROR);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
info_ptr = png_create_info_struct(png_ptr);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!info_ptr)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_read_struct(&png_ptr,
(png_infopp)NULL, (png_infopp)NULL);
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
if (setjmp(png_jmpbuf(png_ptr)))
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_read_struct(&png_ptr, &info_ptr,
(png_infopp)NULL);
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
/* This one's new. You can provide functions
to be called when the header info is valid,
when each row is completed, and when the image
is finished. If you aren't using all functions,
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
you can specify NULL parameters. Even when all
three functions are NULL, you need to call
png_set_progressive_read_fn(). You can use
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
any struct as the user_ptr (cast to a void pointer
for the function call), and retrieve the pointer
from inside the callbacks using the function
png_get_progressive_ptr(png_ptr);
which will return a void pointer, which you have
to cast appropriately.
*/
png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
info_callback, row_callback, end_callback);
return 0;
}
/* A code fragment that you call as you receive blocks
of data */
int
process_data(png_bytep buffer, png_uint_32 length)
{
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
if (setjmp(png_jmpbuf(png_ptr)))
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_read_struct(&png_ptr, &info_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
(png_infopp)NULL);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
/* This one's new also. Simply give it a chunk
of data from the file stream (in order, of
course). On machines with segmented memory
models machines, don't give it any more than
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
64K. The library seems to run fine with sizes
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
of 4K. Although you can give it much less if
necessary (I assume you can give it chunks of
1 byte, I haven't tried less then 256 bytes
yet). When this function returns, you may
want to display any rows that were generated
in the row callback if you don't already do
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
so there.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
*/
png_process_data(png_ptr, info_ptr, buffer, length);
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
/* At this point you can call png_process_data_skip if
you want to handle data the library will skip yourself;
it simply returns the number of bytes to skip (and stops
libpng skipping that number of bytes on the next
png_process_data call).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
return 0;
}
/* This function is called (as set by
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
png_set_progressive_read_fn() above) when enough data
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
has been supplied so all of the header has been
read.
*/
void
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
info_callback(png_structp png_ptr, png_infop info)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
{
/* Do any setup here, including setting any of
the transformations mentioned in the Reading
PNG files section. For now, you _must_ call
either png_start_read_image() or
png_read_update_info() after all the
transformations are set (even if you don't set
any). You may start getting rows before
png_process_data() returns, so this is your
last chance to prepare for that.
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
This is where you turn on interlace handling,
assuming you don't want to do it yourself.
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
If you need to you can stop the processing of
your original input data at this point by calling
png_process_data_pause. This returns the number
of unprocessed bytes from the last png_process_data
call - it is up to you to ensure that the next call
sees these bytes again. If you don't want to bother
with this you can get libpng to cache the unread
bytes by setting the 'save' parameter (see png.h) but
then libpng will have to copy the data internally.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
*/
}
/* This function is called when each row of image
data is complete */
void
row_callback(png_structp png_ptr, png_bytep new_row,
Imported from libpng-1.0.12beta1.tar
2001-05-14 14:20:53 +00:00
png_uint_32 row_num, int pass)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
{
/* If the image is interlaced, and you turned
on the interlace handler, this function will
be called for every row in every pass. Some
of these rows will not be changed from the
previous pass. When the row is not changed,
the new_row variable will be NULL. The rows
and passes are called in order, so you don't
really need the row_num and pass, but I'm
supplying them because it may make your life
easier.
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
If you did not turn on interlace handling then
the callback is called for each row of each
sub-image when the image is interlaced. In this
case 'row_num' is the row in the sub-image, not
the row in the output image as it is in all other
cases.
For the non-NULL rows of interlaced images when
you have switched on libpng interlace handling,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
you must call png_progressive_combine_row()
passing in the row and the old row. You can
call this function for NULL rows (it will just
return) and for non-interlaced images (it just
does the memcpy for you) if it will make the
code easier. Thus, you can just do this for
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
all cases if you switch on interlace handling;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
*/
png_progressive_combine_row(png_ptr, old_row,
new_row);
/* where old_row is what was displayed for
Imported from libpng-1.0.2.tar
1998-06-14 19:43:31 +00:00
previously for the row. Note that the first
pass (pass == 0, really) will completely cover
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
the old row, so the rows do not have to be
initialized. After the first pass (and only
for interlaced images), you will have to pass
the current row, and the function will combine
the old row and the new row.
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
You can also call png_process_data_pause in this
callback - see above.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
*/
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
void
end_callback(png_structp png_ptr, png_infop info)
{
/* This function is called after the whole image
has been read, including any chunks after the
image (up to and including the IEND). You
will usually have the same info chunk as you
had in the header, although some data may have
been added to the comments and time fields.
Most people won't do much here, perhaps setting
a flag that marks the image as finished.
*/
}
Imported from libpng-1.0.1a.tar
1998-04-21 20:03:57 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
.SH IV. Writing
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Much of this is very similar to reading. However, everything of
importance is repeated here, so you won't have to constantly look
back up in the reading section to understand writing.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Setup
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You will want to do the I/O initialization before you get into libpng,
so if it doesn't work, you don't have anything to undo. If you are not
using the standard I/O functions, you will need to replace them with
custom writing functions. See the discussion under Customizing libpng.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
FILE *fp = fopen(file_name, "wb");
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!fp)
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Next, png_struct and png_info need to be allocated and initialized.
As these can be both relatively large, you may not want to store these
on the stack, unless you have stack space to spare. Of course, you
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
will want to check if they return NULL. If you are also reading,
you won't want to name your read structure and your write structure
both "png_ptr"; you can call them anything you like, such as
"read_ptr" and "write_ptr". Look at pngtest.c, for example.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_structp png_ptr = png_create_write_struct
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
(PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
user_error_fn, user_warning_fn);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (!png_ptr)
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
png_destroy_write_struct(&png_ptr,
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
(png_infopp)NULL);
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
If you want to use your own memory allocation routines,
define PNG_USER_MEM_SUPPORTED and use
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
png_create_write_struct_2() instead of png_create_write_struct():
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
png_structp png_ptr = png_create_write_struct_2
(PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
user_error_fn, user_warning_fn, (png_voidp)
user_mem_ptr, user_malloc_fn, user_free_fn);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you have these structures, you will need to set up the
error handling. When libpng encounters an error, it expects to
longjmp() back to your routine. Therefore, you will need to call
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
setjmp() and pass the png_jmpbuf(png_ptr). If you
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
write the file from different routines, you will need to update
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
the png_jmpbuf(png_ptr) every time you enter a new routine that will
call a png_*() function. See your documentation of setjmp/longjmp
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
for your compiler for more information on setjmp/longjmp. See
the discussion on libpng error handling in the Customizing Libpng
section below for more information on the libpng error handling.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
if (setjmp(png_jmpbuf(png_ptr)))
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_destroy_write_struct(&png_ptr, &info_ptr);
Imported from libpng-1.0.7beta15.tar
2000-05-29 13:58:03 +00:00
fclose(fp);
return (ERROR);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
...
return;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
If you would rather avoid the complexity of setjmp/longjmp issues,
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
you can compile libpng with PNG_NO_SETJMP, in which case
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
errors will result in a call to PNG_ABORT() which defaults to abort().
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Checking for invalid palette index on write was added at libpng
1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues
a benign error. This is enabled by default because this condition is an
error according to the PNG specification, Clause 11.3.2, but the error can
be ignored in each png_ptr with
png_set_check_for_invalid_index(png_ptr, 0);
If the error is ignored, or if png_benign_error() treats it as a warning,
any invalid pixels are written as-is by the encoder, resulting in an
invalid PNG datastream as output. In this case the application is
responsible for ensuring that the pixel indexes are in range when it writes
a PLTE chunk with fewer entries than the bit depth would allow.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Now you need to set up the output code. The default for libpng is to
use the C function fwrite(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is
opened in binary mode. Again, if you wish to handle writing data in
another way, see the discussion on libpng I/O handling in the Customizing
Libpng section below.
png_init_io(png_ptr, fp);
Imported from libpng-1.4.0beta2.tar
2006-04-21 02:31:14 +00:00
If you are embedding your PNG into a datastream such as MNG, and don't
want libpng to write the 8-byte signature, or if you have already
written the signature in your application, use
png_set_sig_bytes(png_ptr, 8);
to inform libpng that it should not write a signature.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Write callbacks
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
At this point, you can set up a callback function that will be
called after each row has been written, which you can use to control
a progress meter or the like. It's demonstrated in pngtest.c.
You must supply a function
[devel] Fixed incorrect examples of callback prototypes in the manual. "png_ptr ptr" should be "png_structp png_ptr"
2011-01-24 14:04:37 +00:00
void write_row_callback(png_structp png_ptr, png_uint_32 row,
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
int pass);
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
{
/* put your code here */
}
(You can give it another name that you like instead of "write_row_callback")
To inform libpng about your function, use
png_set_write_status_fn(png_ptr, write_row_callback);
[devel] Fix the read/write row callback documentation.
2011-02-16 12:16:31 +00:00
When this function is called the row has already been completely processed and
it has also been written out. The 'row' and 'pass' refer to the next row to be
handled. For the
non-interlaced case the row that was just handled is simply one less than the
passed in row number, and pass will always be 0. For the interlaced case the
same applies unless the row value is 0, in which case the row just handled was
the last one from one of the preceding passes. Because interlacing may skip a
pass you cannot be sure that the preceding pass is just 'pass-1', if you really
need to know what the last pass is record (row,pass) from the callback and use
the last recorded value each time.
As with the user transform you can find the output row using the
PNG_ROW_FROM_PASS_ROW macro.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You now have the option of modifying how the compression library will
run. The following functions are mainly for testing, but may be useful
in some cases, like if you need to write PNG files extremely fast and
are willing to give up some compression, or if you want to get the
maximum possible compression at the expense of slower writing. If you
have no special needs in this area, let the library do what it wants by
not calling this function at all, as it has been tuned to deliver a good
speed/compression ratio. The second parameter to png_set_filter() is
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
the filter method, for which the only valid values are 0 (as of the
July 1999 PNG specification, version 1.2) or 64 (if you are writing
a PNG datastream that is to be embedded in a MNG datastream). The third
parameter is a flag that indicates which filter type(s) are to be tested
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
for each scanline. See the PNG specification for details on the specific
filter types.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
/* turn on or off filtering, and/or choose
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
specific filters. You can use either a single
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
PNG_FILTER_VALUE_NAME or the bitwise OR of one
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
or more PNG_FILTER_NAME masks.
*/
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_filter(png_ptr, 0,
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
PNG_ALL_FILTERS);
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
If an application wants to start and stop using particular filters during
compression, it should start out with all of the filters (to ensure that
the previous row of pixels will be stored in case it's needed later),
and then add and remove them after the start of compression.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
If you are writing a PNG datastream that is to be embedded in a MNG
datastream, the second parameter can be either 0 or 64.
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
The png_set_compression_*() functions interface to the zlib compression
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
library, and should mostly be ignored unless you really know what you are
doing. The only generally useful call is png_set_compression_level()
which changes how much time zlib spends on trying to compress the image
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
data. See the Compression Library (zlib.h and algorithm.txt, distributed
with zlib) for details on the compression levels.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.2beta03.tar
2011-03-03 12:23:31 +00:00
#include zlib.h
[devel] Updated documentation on setting non-IDAT zlib compression parameters
2011-04-01 20:31:26 +00:00
/* Set the zlib compression level */
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_level(png_ptr,
Z_BEST_COMPRESSION);
[devel] Updated documentation on setting non-IDAT zlib compression parameters
2011-04-01 20:31:26 +00:00
/* Set other zlib parameters for compressing IDAT */
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_mem_level(png_ptr, 8);
png_set_compression_strategy(png_ptr,
Z_DEFAULT_STRATEGY);
png_set_compression_window_bits(png_ptr, 15);
png_set_compression_method(png_ptr, 8);
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
png_set_compression_buffer_size(png_ptr, 8192)
[devel] Updated documentation on setting non-IDAT zlib compression parameters
2011-04-01 20:31:26 +00:00
/* Set zlib parameters for text compression
* If you don't call these, the parameters
* fall back on those defined for IDAT chunks
*/
[devel] Updated manual about the new API additions
2011-04-01 05:16:50 +00:00
png_set_text_compression_mem_level(png_ptr, 8);
png_set_text_compression_strategy(png_ptr,
Z_DEFAULT_STRATEGY);
png_set_text_compression_window_bits(png_ptr, 15);
png_set_text_compression_method(png_ptr, 8);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Setting the contents of info for output
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You now need to fill in the png_info structure with all the data you
wish to write before the actual image. Note that the only thing you
are allowed to write after the image is the text chunks and the time
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
chunk (as of PNG Specification 1.2, anyway). See png_write_end() and
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
the latest PNG specification for more information on that. If you
wish to write them before the image, fill them in now, and flag that
data as being valid. If you want to wait until after the data, don't
fill them until png_write_end(). For all the fields in png_info and
their data types, see png.h. For explanations of what the fields
contain, see the PNG specification.
Some of the more important parts of the png_info are:
png_set_IHDR(png_ptr, info_ptr, width, height,
bit_depth, color_type, interlace_type,
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
compression_type, filter_method)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
width - holds the width of the image
in pixels (up to 2^31).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
height - holds the height of the image
in pixels (up to 2^31).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
bit_depth - holds the bit depth of one of the
image channels.
(valid values are 1, 2, 4, 8, 16
and depend also on the
color_type. See also significant
bits (sBIT) below).
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
color_type - describes which color/alpha
channels are present.
PNG_COLOR_TYPE_GRAY
(bit depths 1, 2, 4, 8, 16)
PNG_COLOR_TYPE_GRAY_ALPHA
(bit depths 8, 16)
PNG_COLOR_TYPE_PALETTE
(bit depths 1, 2, 4, 8)
PNG_COLOR_TYPE_RGB
(bit_depths 8, 16)
PNG_COLOR_TYPE_RGB_ALPHA
(bit_depths 8, 16)
PNG_COLOR_MASK_PALETTE
PNG_COLOR_MASK_COLOR
PNG_COLOR_MASK_ALPHA
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
interlace_type - PNG_INTERLACE_NONE or
PNG_INTERLACE_ADAM7
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
compression_type - (must be
PNG_COMPRESSION_TYPE_DEFAULT)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
filter_method - (must be PNG_FILTER_TYPE_DEFAULT
or, if you are writing a PNG to
be embedded in a MNG datastream,
can also be
PNG_INTRAPIXEL_DIFFERENCING)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
If you call png_set_IHDR(), the call must appear before any of the
[devel] Imported from libpng-1.4.0beta63.tar
2009-06-16 02:56:14 +00:00
other png_set_*() functions, because they might require access to some of
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
the IHDR settings. The remaining png_set_*() functions can be called
in any order.
[devel] Revise libpng.3 about calling png_set_IHDR() multiple times and about the order of color samples in the tRNS chunk.
2009-06-08 13:36:19 +00:00
If you wish, you can reset the compression_type, interlace_type, or
filter_method later by calling png_set_IHDR() again; if you do this, the
width, height, bit_depth, and color_type must be the same in each call.
Imported from libpng-1.4.0beta62.tar
2009-06-02 18:45:15 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_PLTE(png_ptr, info_ptr, palette,
num_palette);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
palette - the palette for the file
(array of png_color)
num_palette - number of entries in the palette
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
png_set_gAMA(png_ptr, info_ptr, file_gamma);
png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
file_gamma - the gamma at which the image was
created (PNG_INFO_gAMA)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
int_file_gamma - 100,000 times the gamma at which
the image was created
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Describe the new XYZ APIs in the manual.
2011-08-25 22:48:18 +00:00
png_set_cHRM(png_ptr, info_ptr, white_x, white_y, red_x, red_y,
green_x, green_y, blue_x, blue_y)
png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
green_Y, green_Z, blue_X, blue_Y, blue_Z)
png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
int_red_x, int_red_y, int_green_x, int_green_y,
int_blue_x, int_blue_y)
png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
int_red_Z, int_green_X, int_green_Y, int_green_Z,
int_blue_X, int_blue_Y, int_blue_Z)
{white,red,green,blue}_{x,y}
A color space encoding specified using the chromaticities
of the end points and the white point.
{red,green,blue}_{X,Y,Z}
A color space encoding specified using the encoding end
points - the CIE tristimulus specification of the intended
color of the red, green and blue channels in the PNG RGB
data. The white point is simply the sum of the three end
points.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_sRGB(png_ptr, info_ptr, srgb_intent);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
srgb_intent - the rendering intent
(PNG_INFO_sRGB) The presence of
the sRGB chunk means that the pixel
data is in the sRGB color space.
This chunk also implies specific
values of gAMA and cHRM. Rendering
intent is the CSS-1 property that
has been defined by the International
Color Consortium
(http://www.color.org).
It can be one of
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
PNG_sRGB_INTENT_SATURATION,
PNG_sRGB_INTENT_PERCEPTUAL,
PNG_sRGB_INTENT_ABSOLUTE, or
PNG_sRGB_INTENT_RELATIVE.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
srgb_intent);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
srgb_intent - the rendering intent
(PNG_INFO_sRGB) The presence of the
sRGB chunk means that the pixel
data is in the sRGB color space.
This function also causes gAMA and
cHRM chunks with the specific values
that are consistent with sRGB to be
written.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
png_set_iCCP(png_ptr, info_ptr, name, compression_type,
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
profile, proflen);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
name - The profile name.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
compression_type - The compression type; always
PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
You may give NULL to this argument to
ignore it.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
profile - International Color Consortium color
profile data. May contain NULs.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Updated documentation of png_set_iCCP().
2011-01-15 17:43:28 +00:00
proflen - length of profile data in bytes.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_sBIT(png_ptr, info_ptr, sig_bit);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
sig_bit - the number of significant bits for
(PNG_INFO_sBIT) each of the gray, red,
green, and blue channels, whichever are
appropriate for the given color type
(png_color_16)
[devel] Bumpt to version libpng-1.4.0beta74
2009-08-08 21:33:14 +00:00
png_set_tRNS(png_ptr, info_ptr, trans_alpha,
num_trans, trans_color);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Bumpt to version libpng-1.4.0beta74
2009-08-08 21:33:14 +00:00
trans_alpha - array of alpha (transparency)
entries for palette (PNG_INFO_tRNS)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
num_trans - number of transparent entries
(PNG_INFO_tRNS)
[devel] Revise libpng.3 about calling png_set_IHDR() multiple times and about the order of color samples in the tRNS chunk.
2009-06-08 13:36:19 +00:00
trans_color - graylevel or color sample values
(in order red, green, blue) of the
single transparent color for
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
non-paletted images (PNG_INFO_tRNS)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_hIST(png_ptr, info_ptr, hist);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
hist - histogram of palette (array of
[devel] Made the manual, synopses, and function prototypes use the function argument names file_gamma, int_file_gamma, and srgb_intent consistently.
2011-01-26 04:15:58 +00:00
png_uint_16) (PNG_INFO_hIST)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_tIME(png_ptr, info_ptr, mod_time);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
mod_time - time image was last modified
(PNG_VALID_tIME)
png_set_bKGD(png_ptr, info_ptr, background);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[devel] Fixed some typos in the manual.
2011-07-10 00:35:22 +00:00
background - background color (of type
png_color_16p) (PNG_VALID_bKGD)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_text(png_ptr, info_ptr, text_ptr, num_text);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
text_ptr - array of png_text holding image
comments
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].compression - type of compression used
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
on "text" PNG_TEXT_COMPRESSION_NONE
PNG_TEXT_COMPRESSION_zTXt
PNG_ITXT_COMPRESSION_NONE
PNG_ITXT_COMPRESSION_zTXt
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].key - keyword for comment. Must contain
1-79 characters.
text_ptr[i].text - text comments for current
keyword. Can be NULL or empty.
text_ptr[i].text_length - length of text string,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
after decompression, 0 for iTXt
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].itxt_length - length of itxt string,
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
after decompression, 0 for tEXt/zTXt
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
text_ptr[i].lang - language of comment (NULL or
empty for unknown).
text_ptr[i].translated_keyword - keyword in UTF-8 (NULL
or empty for unknown).
[libpng15] Updated the documentation of the png_text structure (clarifying that the "lang" and "lang_key" fields can be NULL pointers or might not exist).
2011-11-21 23:05:41 +00:00
[devel] Imported from libpng-1.4.0beta89.tar
2009-11-01 02:31:08 +00:00
Note that the itxt_length, lang, and lang_key
[libpng15] Updated the documentation of the png_text structure (clarifying that the "lang" and "lang_key" fields can be NULL pointers or might not exist).
2011-11-21 23:05:41 +00:00
members of the text_ptr structure only exist when the
library is built with iTXt chunk support. Prior to
libpng-1.4.0 the library was built by default without
iTXt support. Also note that when iTXt is supported,
they contain NULL pointers when the "compression"
field contains PNG_TEXT_COMPRESSION_NONE or
PNG_TEXT_COMPRESSION_zTXt.
[devel] Imported from libpng-1.4.0beta89.tar
2009-11-01 02:31:08 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
num_text - number of comments
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
num_spalettes);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
palette_ptr - array of png_sPLT_struct structures
to be added to the list of palettes
in the info structure.
num_spalettes - number of palette structures to be
added.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
unit_type);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
offset_x - positive offset from the left
edge of the screen
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
offset_y - positive offset from the top
edge of the screen
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
unit_type);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
res_x - pixels/unit physical resolution
in x direction
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
res_y - pixels/unit physical resolution
in y direction
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
unit_type - PNG_RESOLUTION_UNKNOWN,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG_RESOLUTION_METER
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
png_set_sCAL(png_ptr, info_ptr, unit, width, height)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unit - physical scale units (an integer)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
width - width of a pixel in physical scale units
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
height - height of a pixel in physical scale units
(width and height are doubles)
png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unit - physical scale units (an integer)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
width - width of a pixel in physical scale units
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
expressed as a string
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
height - height of a pixel in physical scale units
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
(width and height are strings like "2.54")
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
num_unknowns)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
unknowns - array of png_unknown_chunk
structures holding unknown chunks
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
unknowns[i].name - name of unknown chunk
unknowns[i].data - data of unknown chunk
Imported from libpng-1.0.6f.tar
2000-04-14 19:20:47 +00:00
unknowns[i].size - size of unknown chunk's data
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
unknowns[i].location - position to write chunk in file
0: do not write chunk
PNG_HAVE_IHDR: before PLTE
PNG_HAVE_PLTE: before IDAT
PNG_AFTER_IDAT: after IDAT
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
The "location" member is set automatically according to
what part of the output file has already been written.
You can change its value after calling png_set_unknown_chunks()
as demonstrated in pngtest.c. Within each of the "locations",
the chunks are sequenced according to their position in the
structure (that is, the value of "i", which is the order in which
the chunk was either read from the input file or defined with
png_set_unknown_chunks).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
A quick word about text and num_text. text is an array of png_text
structures. num_text is the number of valid structures in the array.
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
Each png_text structure holds a language code, a keyword, a text value,
and a compression type.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The compression types have the same valid numbers as the compression
types of the image data. Currently, the only valid number is zero.
However, you can store text either compressed or uncompressed, unlike
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
images, which always have to be compressed. So if you don't want the
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
Because tEXt and zTXt chunks don't have a language field, if you
specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
any language code or translated keyword will not be written out.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
Until text gets around a few hundred bytes, it is not worth compressing it.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After the text has been written out to the file, the compression type
is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
so that it isn't written out again at the end (in case you are calling
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
png_write_end() with the same struct).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The keywords that are given in the PNG Specification are:
Title Short (one line) title or
caption for image
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Author Name of image's creator
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Description Description of image (possibly long)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Copyright Copyright notice
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Creation Time Time of original image creation
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
(usually RFC 1123 format, see below)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Software Software used to create the image
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Disclaimer Legal disclaimer
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Warning Warning of nature of content
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Source Device used to create the image
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Comment Miscellaneous comment; conversion
from other image format
The keyword-text pairs work like this. Keywords should be short
simple descriptions of what the comment is about. Some typical
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
keywords are found in the PNG specification, as is some recommendations
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
on keywords. You can repeat keywords in a file. You can even write
some text before the image and some after. For example, you may want
to put a description of the image before the image, but leave the
disclaimer until after, so viewers working over modem connections
don't have to wait for the disclaimer to go over the modem before
they start seeing the image. Finally, keywords should be full
words, not abbreviations. Keywords and text are in the ISO 8859-1
(Latin-1) character set (a superset of regular ASCII) and can not
contain NUL characters, and should not contain control or other
unprintable characters. To make the comments widely readable, stick
with basic ASCII, and avoid machine specific character set extensions
like the IBM-PC character set. The keyword must be present, but
you can leave off the text string on non-compressed pairs.
Compressed pairs must have a text string, as only the text string
is compressed anyway, so the compression would be meaningless.
PNG supports modification time via the png_time structure. Two
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
conversion routines are provided, png_convert_from_time_t() for
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
time_t and png_convert_from_struct_tm() for struct tm. The
time_t routine uses gmtime(). You don't have to use either of
these, but if you wish to fill in the png_time structure directly,
you should provide the time in universal time (GMT) if possible
instead of your local time. Note that the year number is the full
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
that months start with 1.
If you want to store the time of the original image creation, you should
use a plain tEXt chunk with the "Creation Time" keyword. This is
necessary because the "creation time" of a PNG image is somewhat vague,
depending on whether you mean the PNG file, the time the image was
created in a non-PNG format, a still photo from which the image was
scanned, or possibly the subject matter itself. In order to facilitate
machine-readable dates, it is recommended that the "Creation Time"
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
although this isn't a requirement. Unlike the tIME chunk, the
"Creation Time" tEXt chunk is not expected to be automatically changed
by the software. To facilitate the use of RFC 1123 dates, a function
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to
convert from PNG time to an RFC 1123 format string. The caller must provide
a writeable buffer of at least 29 bytes.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Writing unknown chunks
[libpng16] Expanded manual paragraph about writing private chunks, particularly about the need to call png_set_keep_unknown_chunks() when writing them.
2013-04-27 23:03:03 +00:00
You can use the png_set_unknown_chunks function to queue up private chunks
for writing. You give it a chunk name, location, raw data, and a size. You
also must use png_set_keep_unknown_chunks() to ensure that libpng will
handle them. That's all there is to it. The chunks will be written by the
next following png_write_info_before_PLTE, png_write_info, or png_write_end
function, depending upon the specified location. Any chunks previously
read into the info structure's unknown-chunk list will also be written out
in a sequence that satisfies the PNG specification's ordering rules.
Here is an example of writing two private chunks, prVt and miNE:
#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
/* Set unknown chunk data */
[libpng16] Revise man page to demonstrate dealing with unknown chunk handling in libpng.1.5.x and with bugs in libpng-1.4.x and earlier.
2013-04-29 01:48:37 +00:00
png_unknown_chunk unk_chunk[2];
strcpy((char *) unk_chunk[0].name, "prVt";
unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
unk_chunk[0].location = PNG_HAVE_IHDR;
strcpy((char *) unk_chunk[1].name, "miNE";
unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
unk_chunk[1].location = PNG_AFTER_IDAT;
png_set_unknown_chunks(write_ptr, write_info_ptr,
unk_chunk, 2);
/* Needed because miNE is not safe-to-copy */
png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
(png_bytep) "miNE", 1);
# if PNG_LIBPNG_VER < 10600
/* Deal with unknown chunk location bug in 1.5.x and earlier */
png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
# endif
# if PNG_LIBPNG_VER < 10500
/* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
* one before IDAT and another after IDAT, so don't use it; only use
* PNG_HAVE_IHDR location. This call resets the location previously
* set by assignment and png_set_unknown_chunk_location() for chunk 1.
*/
png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
# endif
[libpng16] Expanded manual paragraph about writing private chunks, particularly about the need to call png_set_keep_unknown_chunks() when writing them.
2013-04-27 23:03:03 +00:00
#endif
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS The high-level write interface
At this point there are two ways to proceed; through the high-level
write interface, or through a sequence of low-level write operations.
You can use the high-level interface if your image data is present
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
in the info structure. All defined output
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
transformations are permitted, enabled by the following masks.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_IDENTITY No transformation
PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
PNG_TRANSFORM_PACKSWAP Change order of packed
pixels to LSB first
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_INVERT_MONO Invert monochrome images
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
PNG_TRANSFORM_SHIFT Normalize pixels to the
sBIT depth
PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
to BGRA
PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
to AG
PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
to transparency
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
Imported from libpng-1.4.0beta46.tar
2008-12-10 13:14:45 +00:00
PNG_TRANSFORM_STRIP_FILLER Strip out filler
bytes (deprecated).
PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
filler bytes
PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing
filler bytes
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
If you have valid image data in the info structure (you can use
png_set_rows() to put image data in the info structure), simply do this:
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
png_write_png(png_ptr, info_ptr, png_transforms, NULL)
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
where png_transforms is an integer containing the bitwise OR of some set of
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
transformation flags. This call is equivalent to png_write_info(),
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
followed the set of transformations indicated by the transform mask,
then png_write_image(), and finally png_write_end().
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
(The final parameter of this call is not yet used. Someday it might point
to transformation parameters required by some future output transform.)
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
You must use png_transforms and not call any png_set_transform() functions
when you use png_write_png().
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS The low-level write interface
If you are going the low-level route instead, you are now ready to
write all the file information up to the actual image data. You do
this with a call to png_write_info().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_write_info(png_ptr, info_ptr);
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
Note that there is one transformation you may need to do before
png_write_info(). In PNG files, the alpha channel in an image is the
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
level of opacity. If your data is supplied as a level of transparency,
you can invert the alpha channel before you write it, so that 0 is
fully transparent and 255 (in 8-bit or paletted images) or 65535
(in 16-bit images) is fully opaque, with
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
png_set_invert_alpha(png_ptr);
This must appear before png_write_info() instead of later with the
other transformations because in the case of paletted images the tRNS
chunk data has to be inverted before the tRNS chunk is written. If
your image is not a paletted image, the tRNS data (which in such cases
represents a single color to be rendered as transparent) won't need to
be changed, and you can safely do this transformation after your
png_write_info() call.
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
If you need to write a private chunk that you want to appear before
the PLTE chunk when PLTE is present, you can write the PNG info in
two steps, and insert code to write your own chunk between them:
png_write_info_before_PLTE(png_ptr, info_ptr);
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
png_set_unknown_chunks(png_ptr, info_ptr, ...);
Imported from libpng-1.0.5c.tar
1999-11-27 16:22:33 +00:00
png_write_info(png_ptr, info_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you've written the file information, you can set up the library
to handle any special transformations of the image data. The various
ways to transform the data will be described in the order that they
should occur. This is important, as some of these change the color
type and/or bit depth of the data, and some others only work on
certain color types and bit depths. Even though each transformation
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
checks to see if it has data that it can do something with, you should
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
make sure to only enable a transformation if it will be valid for the
data. For example, don't swap red and blue on grayscale data.
Imported from libpng-1.0.1a.tar
1998-04-21 20:03:57 +00:00
PNG files store RGB pixels packed into 3 or 6 bytes. This code tells
Imported from libpng-1.0.6a.tar
2000-04-02 03:10:05 +00:00
the library to strip input data that has 4 or 8 bytes per pixel down
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
bytes per pixel).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
is stored XRGB or RGBX.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
they can, resulting in, for example, 8 pixels per byte for 1 bit files.
If the data is supplied at 1 pixel per byte, use this code, which will
correctly pack the pixels into a single byte:
png_set_packing(png_ptr);
PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your
data is of another bit depth, you can write an sBIT chunk into the
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
file so that decoders can recover the original data if desired.
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
/* Set the true bit depth of the image data */
if (color_type & PNG_COLOR_MASK_COLOR)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
sig_bit.red = true_bit_depth;
sig_bit.green = true_bit_depth;
sig_bit.blue = true_bit_depth;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
else
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
sig_bit.gray = true_bit_depth;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (color_type & PNG_COLOR_MASK_ALPHA)
{
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
sig_bit.alpha = true_bit_depth;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
}
png_set_sBIT(png_ptr, info_ptr, &sig_bit);
If the data is stored in the row buffer in a bit depth other than
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
this will scale the values to appear to be the correct bit depth as
is required by PNG.
png_set_shift(png_ptr, &sig_bit);
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
PNG files store 16-bit pixels in network byte order (big-endian,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
ie. most significant bits first). This code would be used if they are
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
supplied the other way (little-endian, i.e. least significant bits
first, the way PCs store them):
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
if (bit_depth > 8)
png_set_swap(png_ptr);
If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
need to change the order the pixels are packed into bytes, you can use:
if (bit_depth < 8)
png_set_packswap(png_ptr);
PNG files store 3 color pixels in red, green, blue order. This code
would be used if they are supplied as blue, green, red:
png_set_bgr(png_ptr);
PNG files describe monochrome as black being zero and white being
one. This code would be used if the pixels are supplied with this reversed
(black being one and white being zero):
png_set_invert_mono(png_ptr);
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
Finally, you can write your own transformation function if none of
the existing ones meets your needs. This is done by setting a callback
with
png_set_write_user_transform_fn(png_ptr,
write_transform_fn);
You must supply the function
[devel] Fixed mistake in the descriptions of user read_transform and write_transform function prototypes in the manual. The row_info struct should be of type png_row_infop.
2011-02-14 01:42:19 +00:00
void write_transform_fn(png_structp png_ptr, png_row_infop
row_info, png_bytep data)
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
See pngtest.c for a working example. Your function will be called
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
before any of the other transformations are processed. If supported
libpng also supplies an information routine that may be called from
your callback:
png_get_current_row_number(png_ptr);
[devel] Correct png_get_current_row_number documentation
2011-02-16 12:15:13 +00:00
png_get_current_pass_number(png_ptr);
This returns the current row passed to the transform. With interlaced
images the value returned is the row in the input sub-image image. Use
PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
[devel] Added four new convenience functions (John Bowler)
2011-01-23 00:29:24 +00:00
[devel] Correct png_get_current_row_number documentation
2011-02-16 12:15:13 +00:00
The discussion of interlace handling above contains more information on how to
use these values.
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
You can also set up a pointer to a user structure for use by your
callback function.
png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
The user_channels and user_depth parameters of this function are ignored
when writing; you can set them to zero as shown.
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
You can retrieve the pointer via the function png_get_user_transform_ptr().
For example:
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
voidp write_user_transform_ptr =
png_get_user_transform_ptr(png_ptr);
Imported from libpng-0.99i.tar
1998-03-07 12:06:55 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
It is possible to have libpng flush any pending output, either manually,
or automatically after a certain number of lines have been written. To
flush the output stream a single time call:
png_write_flush(png_ptr);
and to have libpng flush the output stream periodically after a certain
number of scanlines have been written, call:
png_set_flush(png_ptr, nrows);
Note that the distance between rows is from the last time png_write_flush()
was called, or the first row of the image if it has never been called.
So if you write 50 lines, and then png_set_flush 25, it will flush the
output on the next scanline, and every 25 lines thereafter, unless
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
png_write_flush() is called before 25 more lines have been written.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If nrows is too small (less than about 10 lines for a 640 pixel wide
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
RGB image) the image compression may decrease noticeably (although this
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
may be acceptable for real-time applications). Infrequent flushing will
only degrade the compression performance by a few percent over images
that do not use flushing.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Writing the image data
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
That's it for the transformations. Now you can write the image data.
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
The simplest way to do this is in one function call. If you have the
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
whole image in memory, you can just call png_write_image() and libpng
will write the image. You will need to pass in an array of pointers to
each row. This function automatically handles interlacing, so you don't
need to call png_set_interlace_handling() or call this function multiple
times, or any of that other stuff necessary with png_write_rows().
png_write_image(png_ptr, row_pointers);
where row_pointers is:
Imported from libpng-1.0.1a.tar
1998-04-21 20:03:57 +00:00
png_byte *row_pointers[height];
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You can point to void or char or whatever you use for pixels.
Imported from libpng-1.0.1a.tar
1998-04-21 20:03:57 +00:00
If you don't want to write the whole image at once, you can
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
use png_write_rows() instead. If the file is not interlaced,
this is simple:
png_write_rows(png_ptr, row_pointers,
number_of_rows);
row_pointers is the same as in the png_write_image() call.
If you are just writing one row at a time, you can do this with
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
a single row_pointer instead of an array of row_pointers:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_bytep row_pointer = row;
Imported from libpng-1.0.6.tar
2000-03-21 11:13:06 +00:00
png_write_row(png_ptr, row_pointer);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
When the file is interlaced, things can get a good deal more complicated.
The only currently (as of the PNG Specification version 1.2, dated July
1999) defined interlacing scheme for PNG files is the "Adam7" interlace
scheme, that breaks down an image into seven smaller images of varying
size. libpng will build these images for you, or you can do them
yourself. If you want to build them yourself, see the PNG specification
for details of which pixels to write when.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you don't want libpng to handle the interlacing details, just
use png_set_interlace_handling() and call png_write_rows() the
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
correct number of times to write all the sub-images
(png_set_interlace_handling() returns the number of sub-images.)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you want libpng to build the sub-images, call this before you start
writing any rows:
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
number_of_passes = png_set_interlace_handling(png_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
This will return the number of passes needed. Currently, this is seven,
but may change if another interlace type is added.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Then write the complete image number_of_passes times.
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
png_write_rows(png_ptr, row_pointers, number_of_rows);
Think carefully before you write an interlaced image. Typically code that
reads such images reads all the image data into memory, uncompressed, before
doing any processing. Only code that can display an image on the fly can
take advantage of the interlacing and even then the image has to be exactly
the correct size for the output device, because scaling an image requires
adjacent pixels and these are not available until all the passes have been
read.
If you do write an interlaced image you will hardly ever need to handle
the interlacing yourself. Call png_set_interlace_handling() and use the
approach described above.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
The only time it is conceivable that you will really need to write an
interlaced image pass-by-pass is when you have read one pass by pass and
made some pixel-by-pixel transformation to it, as described in the read
code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
to determine the size of each sub-image in turn and simply write the rows
you obtained from the read code.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Finishing a sequential write
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
After you are finished writing the image, you should finish writing
the file. If you are interested in writing comments or time, you should
pass an appropriately filled png_info pointer. If you are not interested,
you can pass NULL.
png_write_end(png_ptr, info_ptr);
When you are done, you can free all memory used by libpng like this:
png_destroy_write_struct(&png_ptr, &info_ptr);
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
It is also possible to individually free the info_ptr members that
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
point to libpng-allocated storage with the following function:
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_free_data(png_ptr, info_ptr, mask, seq)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
mask - identifies data to be freed, a mask
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
containing the bitwise OR of one or
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
more of
PNG_FREE_PLTE, PNG_FREE_TRNS,
PNG_FREE_HIST, PNG_FREE_ICCP,
PNG_FREE_PCAL, PNG_FREE_ROWS,
PNG_FREE_SCAL, PNG_FREE_SPLT,
PNG_FREE_TEXT, PNG_FREE_UNKN,
or simply PNG_FREE_ALL
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
seq - sequence number of item to be freed
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
(-1 for all items)
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-1.0.7beta14.tar
2000-05-17 22:39:34 +00:00
This function may be safely called when the relevant storage has
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
already been freed, or has not yet been allocated, or was allocated
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
by the user and not by libpng, and will in those cases do nothing.
The "seq" parameter is ignored if only one item of the selected data
type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
are allowed for the data type identified in the mask, such as text or
sPLT, only the n'th item in the structure is freed, where n is "seq".
If you allocated data such as a palette that you passed in to libpng
with png_set_*, you must not free it until just before the call to
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
png_destroy_write_struct().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
The default behavior is only to free data that was allocated internally
by libpng. This can be changed, so that libpng will not free the data,
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
or so that it will free data that was allocated by the user with png_malloc()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
or png_calloc() and passed in via a png_set_*() function, with
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
png_data_freer(png_ptr, info_ptr, freer, mask)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
freer - one of
PNG_DESTROY_WILL_FREE_DATA
PNG_SET_WILL_FREE_DATA
PNG_USER_WILL_FREE_DATA
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
mask - which data elements are affected
same choices as in png_free_data()
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
For example, to transfer responsibility for some data from a read structure
to a write structure, you could use
png_data_freer(read_ptr, read_info_ptr,
PNG_USER_WILL_FREE_DATA,
PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
png_data_freer(write_ptr, write_info_ptr,
PNG_DESTROY_WILL_FREE_DATA,
PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
thereby briefly reassigning responsibility for freeing to the user but
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
immediately afterwards reassigning it once more to the write_destroy
function. Having done this, it would then be safe to destroy the read
structure and continue to use the PLTE, tRNS, and hIST data in the write
structure.
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
This function only affects data that has already been allocated.
You can call this function before calling after the png_set_*() functions
to control whether the user or png_destroy_*() is supposed to free the data.
When the user assumes responsibility for libpng-allocated data, the
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
application must use
png_free() to free it, and when the user transfers responsibility to libpng
for data that the user has allocated, the user must have used png_malloc()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
or png_calloc() to allocate it.
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
separately, do not transfer responsibility for freeing text_ptr to libpng,
because when libpng fills a png_text structure it combines these members with
the key member, and png_free_data() will free only text_ptr.key. Similarly,
if you transfer responsibility for free'ing text_ptr from libpng to your
application, your application must not separately free those members.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
For a more compact example of writing a PNG image, see the file example.c.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH V. Simplified API
The simplified API, which became available in libpng-1.6.0, hides the details
of both libpng and the PNG file format itself.
It allows PNG files to be read into a very limited number of
in-memory bitmap formats or to be written from the same formats. If these
formats do not accomodate your needs then you can, and should, use the more
sophisticated APIs above - these support a wide variety of in-memory formats
and a wide variety of sophisticated transformations to those formats as well
as a wide variety of APIs to manipulate ancilliary information.
To read a PNG file using the simplified API:
1) Declare a 'png_image' structure (see below) on the
stack and memset() it to all zero.
2) Call the appropriate png_image_begin_read... function.
3) Set the png_image 'format' member to the required
format and allocate a buffer for the image.
4) Call png_image_finish_read to read the image into
your buffer.
There are no restrictions on the format of the PNG input itself; all valid
color types, bit depths, and interlace methods are acceptable, and the
input image is transformed as necessary to the requested in-memory format
during the png_image_finish_read() step.
To write a PNG file using the simplified API:
1) Declare a 'png_image' structure on the stack and memset()
it to all zero.
2) Initialize the members of the structure that describe the
image, setting the 'format' member to the format of the
image in memory.
3) Call the appropriate png_image_write... function with a
pointer to the image to write the PNG data.
png_image is a structure that describes the in-memory format of an image
when it is being read or define the in-memory format of an image that you
need to write. The "png_image" structure contains the following members:
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_uint_32 version Set to PNG_IMAGE_VERSION
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
png_uint_32 width Image width in pixels (columns)
png_uint_32 height Image height in pixels (rows)
png_uint_32 format Image format as defined below
png_uint_32 flags A bit mask containing informational flags
png_controlp opaque Initialize to NULL, free with png_image_free
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_uint_32 colormap_entries; Number of entries in the color-map
png_uint_32 warning_or_error;
char message[64];
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
In the event of an error or warning the following field warning_or_error
field will be set to a non-zero value and the 'message' field will contain
a '\0' terminated string with the libpng error or warning message. If both
warnings and an error were encountered, only the error is recorded. If there
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
are multiple warnings, only the first one is recorded.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The upper 30 bits of this value are reserved; the low two bits contain
a two bit code such that a value more than 1 indicates a failure in the API
just called:
[libpng16] Imported from libpng-1.6.0beta05.tar
2012-02-03 05:11:45 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
0 - no warning or error
1 - warning
2 - error
3 - error preceded by warning
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
The pixels (samples) of the image have one to four channels whose components
have original values in the range 0 to 1.0:
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
1: A single gray or luminance channel (G).
2: A gray/luminance channel and an alpha channel (GA).
3: Three red, green, blue color channels (RGB).
4: Three color channels and an alpha channel (RGBA).
The channels are encoded in one of two ways:
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
a) As a small integer, value 0..255, contained in a single byte. For the
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
alpha channel the original value is simply value/255. For the color or
luminance channels the value is encoded according to the sRGB specification
and matches the 8-bit format expected by typical display devices.
The color/gray channels are not scaled (pre-multiplied) by the alpha
channel and are suitable for passing to color management software.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
b) As a value in the range 0..65535, contained in a 2-byte integer. All
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
channels can be converted to the original value by dividing by 65535; all
channels are linear. Color channels use the RGB encoding (RGB end-points) of
the sRGB specification. This encoding is identified by the
PNG_FORMAT_FLAG_LINEAR flag below.
When an alpha channel is present it is expected to denote pixel coverage
of the color or luminance channels and is returned as an associated alpha
channel: the color/gray channels are scaled (pre-multiplied) by the alpha
value.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
When a color-mapped image is used as a result of calling
png_image_read_colormap or png_image_write_colormap the channels are encoded
in the color-map and the descriptions above apply to the color-map entries.
The image data is encoded as small integers, value 0..255, that index the
entries in the color-map. One integer (one byte) is stored for each pixel.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
PNG_FORMAT_*
The #defines to be used in png_image::format. Each #define identifies a
particular layout of channel data and, if present, alpha values. There are
separate defines for each of the two channel encodings.
A format is built up using single bit flag values. Not all combinations are
valid: use the bit flag values below for testing a format returned by the
read APIs, but set formats from the derived values.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
When reading or writing color-mapped images the format should be set to the
format of the entries in the color-map then png_image_{read,write}_colormap
called to read or write the color-map and set the format correctly for the
image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
NOTE: libpng can be built with particular features disabled, if you see
compiler errors because the definition of one of the following flags has been
compiled out it is because libpng does not have the required support. It is
possible, however, for the libpng configuration to enable the format on just
read or just write; in that case you may see an error at run time. You can
guard against this by checking for the definition of:
PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
PNG_FORMAT_FLAG_ALPHA 0x01 format with an alpha channel
PNG_FORMAT_FLAG_COLOR 0x02 color format: otherwise grayscale
PNG_FORMAT_FLAG_LINEAR 0x04 png_uint_16 channels else png_byte
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_FORMAT_FLAG_COLORMAP 0x08 libpng use only
PNG_FORMAT_FLAG_BGR 0x10 BGR colors, else order is RGB
PNG_FORMAT_FLAG_AFIRST 0x20 alpha channel comes first
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
Supported formats are as follows. Future versions of libpng may support more
formats; for compatibility with older versions simply check if the format
macro is defined using #ifdef. These defines describe the in-memory layout
of the components of the pixels of the image.
First the single byte formats:
PNG_FORMAT_GRAY 0
PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Then the linear 2-byte formats. When naming these "Y" is used to
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
indicate a luminance (gray) channel. The component order within the pixel
is always the same - there is no provision for swapping the order of the
components in the linear format.
PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
PNG_FORMAT_LINEAR_Y_ALPHA
(PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
PNG_FORMAT_LINEAR_RGB
(PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
PNG_FORMAT_LINEAR_RGB_ALPHA
(PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|
PNG_FORMAT_FLAG_ALPHA)
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Color-mapped formats are obtained by calling png_image_{read,write}_colormap,
as appropriate after setting png_image::format to the format of the color-map
to be read or written. Applications may check the value of
PNG_FORMAT_FLAG_COLORMAP to see if they have called the colormap API. The
format of the color-map may be extracted using the following macro.
PNG_FORMAT_OF_COLORMAP(fmt) ((fmt) & ~PNG_FORMAT_FLAG_COLORMAP)
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
PNG_IMAGE macros
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
These are convenience macros to derive information from a png_image
structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
actual image sample values - either the entries in the color-map or the
pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
for the pixels and will always return 1 after a call to
png_image_{read,write}_colormap. The remaining macros return information
about the rows in the image and the complete image.
NOTE: All the macros that take a png_image::format parameter are compile time
constants if the format parameter is, itself, a constant. Therefore these
macros can be used in array declarations and case labels where required.
Similarly the macros are also pre-processor constants (sizeof is not used) so
they can be used in #if tests.
First the information about the samples.
[libpng16] Imported from libpng-1.6.0beta06.tar
2012-01-24 13:33:26 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_SAMPLE_CHANNELS(fmt)
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
Returns the total number of channels in a given format: 1..4
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
Returns the size in bytes of a single component of a pixel or color-map
entry (as appropriate) in the image.
PNG_IMAGE_SAMPLE_SIZE(fmt)
This is the size of the sample data for one sample. If the image is
color-mapped it is the size of one color-map entry (and image pixels are
one byte in size), otherwise it is the size of one image pixel.
PNG_IMAGE_COLORMAP_SIZE(fmt)
The size of the color-map required by the format; this is the size of the
color-map buffer passed to the png_image_{read,write}_colormap APIs, it is
a fixed number determined by the format so can easily be allocated on the
stack if necessary.
#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
(PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
/* The maximum size of the color-map required by the format expressed in a
* count of components. This can be used to compile-time allocate a
* color-map:
*
* png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
*
* png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
*
* Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
* information from one of the png_image_begin_read_ APIs and dynamically
* allocate the required memory.
*/
Corresponding information about the pixels
PNG_IMAGE_PIXEL_(test,fmt)
PNG_IMAGE_PIXEL_CHANNELS(fmt)
The number of separate channels (components) in a pixel; 1 for a
color-mapped image.
PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
The size, in bytes, of each component in a pixel; 1 for a color-mapped
image.
[libpng16] Remove whitespace at end of lines
2012-03-02 19:13:15 +00:00
[libpng16] Fixed some editing cruft in libpng-manual.txt and libpng.3
2012-02-04 03:14:33 +00:00
PNG_IMAGE_PIXEL_SIZE(fmt)
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The size, in bytes, of a complete pixel; 1 for a color-mapped image.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Information about the whole row, or whole image
[libpng16] Imported from libpng-1.6.0beta05.tar
2012-02-03 05:11:45 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_ROW_STRIDE(image)
Returns the total number of components in a single row of the image; this
is the minimum 'row stride', the minimum count of components between each
row. For a color-mapped image this is the minimum number of bytes in a
row.
[libpng16] Imported from libpng-1.6.0beta05.tar
2012-02-03 05:11:45 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_BUFFER_SIZE(image, row_stride)
Returns the size, in bytes, of an image buffer given a png_image and a row
stride - the number of components to leave space for in each row.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
This indicates the the RGB values of the in-memory bitmap do not
correspond to the red, green and blue end-points defined by sRGB.
[libpng16] Remove whitespace at end of lines
2012-03-02 19:13:15 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
PNG_IMAGE_FLAG_COLORMAP == 0x02
The PNG is color-mapped. If this flag is set png_image_read_colormap
can be used without further loss of image information. If it is not set
png_image_read_colormap will cause significant loss if the image has any
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
READ APIs
The png_image passed to the read APIs must have been initialized by setting
the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
int png_image_begin_read_from_file( png_imagep image,
const char *file_name)
The named file is opened for read and the image header
is filled in from the PNG header in the file.
int png_image_begin_read_from_stdio (png_imagep image,
FILE* file)
The PNG header is read from the stdio FILE object.
int png_image_begin_read_from_memory(png_imagep image,
png_const_voidp memory, png_size_t size)
The PNG header is read from the given memory buffer.
int png_image_finish_read(png_imagep image,
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_colorp background, void *buffer,
png_int_32 row_stride, void *colormap));
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
Finish reading the image into the supplied buffer and
clean up the png_image structure.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
row_stride is the step, in png_byte or png_uint_16 units
as appropriate, between adjacent rows. A positive stride
indicates that the top-most row is first in the buffer -
the normal top-down arrangement. A negative stride
indicates that the bottom-most row is first in the buffer.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
background need only be supplied if an alpha channel must
be removed from a png_byte format and the removal is to be
done by compositing on a solid color; otherwise it may be
NULL and any composition will be done directly onto the
buffer. The value is an sRGB color to use for the
background, for grayscale output the green channel is used.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
For linear output removing the alpha channel is always done
by compositing on black.
void png_image_free(png_imagep image)
Free any data allocated by libpng in image->opaque,
setting the pointer to NULL. May be called at any time
after the structure is initialized.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
When the simplified API needs to convert between sRGB and linear colorspaces,
the actual sRGB transfer curve defined in the sRGB specification (see the
article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
approximation used elsewhere in libpng.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
WRITE APIS
For write you must initialize a png_image structure to describe the image to
be written:
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
version: must be set to PNG_IMAGE_VERSION
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
opaque: must be initialized to NULL
width: image width in pixels
height: image height in rows
format: the format of the data you wish to write
flags: set to 0 unless one of the defined flags applies; set
PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
where the RGB values do not correspond to the colors in sRGB.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
colormap_entries: set to the number of entries in the color-map (0 to 256)
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
int png_image_write_to_file, (png_imagep image,
const char *file, int convert_to_8bit, const void *buffer,
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_int_32 row_stride, const void *colormap));
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
Write the image to the named file.
int png_image_write_to_stdio(png_imagep image, FILE *file,
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
int convert_to_8_bit, const void *buffer,
png_int_32 row_stride, const void *colormap)
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
Write the image to the given (FILE*).
With all write APIs if image is in one of the linear formats with
(png_uint_16) data then setting convert_to_8_bit will cause the output to be
a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
a 16-bit linear encoded PNG file is written.
With all APIs row_stride is handled as in the read APIs - it is the spacing
from one row to the next in component sized units (float) and if negative
indicates a bottom-up row layout in the buffer.
Note that the write API does not support interlacing, sub-8-bit pixels,
and indexed (paletted) images.
.SH VI. Modifying/Customizing libpng
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
There are two issues here. The first is changing how libpng does
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
standard things like memory allocation, input/output, and error handling.
The second deals with more complicated things like adding new chunks,
adding new transformations, and generally changing how libpng works.
Imported from libpng-1.0.9beta8.tar
2001-01-12 21:13:06 +00:00
Both of those are compile-time issues; that is, they are generally
determined at the time the code is written, and there is rarely a need
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
to provide the user with a means of changing them.
Imported from libpng-1.0.9beta8.tar
2001-01-12 21:13:06 +00:00
Memory allocation, input/output, and error handling
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
All of the memory allocation, input/output, and error handling in libpng
Imported from libpng-1.0.9beta8.tar
2001-01-12 21:13:06 +00:00
goes through callbacks that are user-settable. The default routines are
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
these functions, call the appropriate png_set_*_fn() function.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
Memory allocation is done through the functions png_malloc(), png_calloc(),
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
and png_free(). The png_malloc() and png_free() functions currently just
call the standard C functions and png_calloc() calls png_malloc() and then
clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
is not the same as the calloc(number, size) function provided by stdlib.h.
There is limited support for certain systems with segmented memory
architectures and the types of pointers declared by png.h match this; you
will have to use appropriate pointers in your application. Since it is
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
unlikely that the method of handling memory allocation on a platform
will change between applications, these functions must be modified in
the library at compile time. If you prefer to use a different method
of allocating and freeing data, you can use png_create_read_struct_2() or
png_create_write_struct_2() to register your own functions as described
above. These functions also provide a void pointer that can be retrieved
via
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
mem_ptr=png_get_mem_ptr(png_ptr);
Your replacement memory functions must have prototypes as follows:
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_voidp malloc_fn(png_structp png_ptr,
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
png_alloc_size_t size);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
void free_fn(png_structp png_ptr, png_voidp ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
Your malloc_fn() must return NULL in case of failure. The png_malloc()
function will normally call png_error() if it receives a NULL from the
system memory allocator or from your replacement malloc_fn().
Imported from libpng-1.0.11rc1.tar
2001-04-20 15:32:10 +00:00
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
Your free_fn() will never be called with a NULL ptr, since libpng's
png_free() checks for NULL before calling free_fn().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Input/Output in libpng is done through png_read() and png_write(),
which currently just call fread() and fwrite(). The FILE * is stored in
png_struct and is initialized via png_init_io(). If you wish to change
the method of I/O, the library supplies callbacks that you can set
through the function png_set_read_fn() and png_set_write_fn() at run
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
time, instead of calling the png_init_io() function. These functions
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
also provide a void pointer that can be retrieved via the function
png_get_io_ptr(). For example:
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
png_set_read_fn(png_structp read_ptr,
voidp read_io_ptr, png_rw_ptr read_data_fn)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
png_set_write_fn(png_structp write_ptr,
voidp write_io_ptr, png_rw_ptr write_data_fn,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_flush_ptr output_flush_fn);
Imported from libpng-1.0.1e.tar
1998-06-06 20:31:35 +00:00
voidp read_io_ptr = png_get_io_ptr(read_ptr);
voidp write_io_ptr = png_get_io_ptr(write_ptr);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
The replacement I/O functions must have prototypes as follows:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
void user_read_data(png_structp png_ptr,
Imported from libpng-1.2.3rc5.tar
2002-05-11 01:19:58 +00:00
png_bytep data, png_size_t length);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
void user_write_data(png_structp png_ptr,
Imported from libpng-1.2.3rc5.tar
2002-05-11 01:19:58 +00:00
png_bytep data, png_size_t length);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
void user_flush_data(png_structp png_ptr);
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
The user_read_data() function is responsible for detecting and
handling end-of-data errors.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Supplying NULL for the read, write, or flush functions sets them back
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
to using the default C stream functions, which expect the io_ptr to
point to a standard *FILE structure. It is probably a mistake
to use NULL for one of write_data_fn and output_flush_fn but not both
of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
It is an error to read from a write stream, and vice versa.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Error handling in libpng is done through png_error() and png_warning().
Errors handled through png_error() are fatal, meaning that png_error()
should never return to its caller. Currently, this is handled via
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
setjmp() and longjmp() (unless you have compiled libpng with
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
[devel] Document the fact that png_set_dither() is no longer supported.
2010-04-14 03:11:06 +00:00
but you could change this to do things like exit() if you should wish,
[devel] Slightly expanded the documentation of PNG_ABORT()
2010-04-02 22:06:22 +00:00
as long as your function does not return.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
On non-fatal errors, png_warning() is called
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
to print a warning message, and then control returns to the calling code.
By default png_error() and png_warning() print a message on stderr via
Imported from libpng-1.0.6e.tar
2000-04-10 00:06:13 +00:00
fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
(because you don't want the messages) or PNG_NO_STDIO defined (because
fprintf() isn't available). If you wish to change the behavior of the error
functions, you will need to set up your own message callbacks. These
functions are normally supplied at the time that the png_struct is created.
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
It is also possible to redirect errors and warnings to your own replacement
functions after png_create_*_struct() has been called by calling:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_error_fn(png_structp png_ptr,
png_voidp error_ptr, png_error_ptr error_fn,
png_error_ptr warning_fn);
png_voidp error_ptr = png_get_error_ptr(png_ptr);
If NULL is supplied for either error_fn or warning_fn, then the libpng
default function will be used, calling fprintf() and/or longjmp() if a
problem is encountered. The replacement error functions should have
parameters as follows:
void user_error_fn(png_structp png_ptr,
png_const_charp error_msg);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
void user_warning_fn(png_structp png_ptr,
png_const_charp warning_msg);
The motivation behind using setjmp() and longjmp() is the C++ throw and
catch exception handling methods. This makes the code much easier to write,
as there is no need to check every return code of every function call.
However, there are some uncertainties about the status of local variables
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
after a longjmp, so the user may want to be careful about doing anything
after setjmp returns non-zero besides returning itself. Consult your
compiler documentation for more details. For an alternative approach, you
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
which is illustrated in pngvalid.c and in contrib/visupng.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
You can use this to handle certain errors (normally handled as errors)
as warnings.
png_set_benign_errors (png_ptr, int allowed);
allowed: 0: (default) treat png_benign_error() an error.
1: treat png_benign_error() as a warning.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Custom chunks
If you need to read or write custom chunks, you may need to get deeper
into the libpng code. The library now has mechanisms for storing
and writing chunks of unknown type; you can even declare callbacks
Imported from libpng-1.2.9beta1.tar
2006-02-21 04:09:05 +00:00
for custom chunks. However, this may not be good enough if the
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
library code itself needs to know about interactions between your
chunk and existing `intrinsic' chunks.
If you need to write a new intrinsic chunk, first read the PNG
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
specification. Acquire a first level of understanding of how it works.
Pay particular attention to the sections that describe chunk names,
and look at how other chunks were designed, so you can do things
similarly. Second, check out the sections of libpng that read and
write chunks. Try to find a chunk that is similar to yours and use
it as a template. More details can be found in the comments inside
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
the code. It is best to handle private or unknown chunks in a generic method,
via callback functions, instead of by modifying libpng functions. This
is illustrated in pngtest.c, which uses a callback function to handle a
private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
libpng.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you wish to write your own transformation for the data, look through
the part of the code that does the transformations, and check out some of
the simpler ones to get an idea of how they work. Try to find a similar
transformation to the one you want to add and copy off of it. More details
can be found in the comments inside the code itself.
[devel] Fix typos and indentation in new material in the documentation.
2011-05-13 03:18:23 +00:00
.SS Configuring for 16-bit platforms
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
You will want to look into zconf.h to tell zlib (and thus libpng) that
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
it cannot allocate more then 64K at a time. Even if you can, the memory
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Configuring for DOS
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
For DOS users who only have access to the lower 640K, you will
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
have to limit zlib's memory usage via a png_set_compression_mem_level()
call. See zlib.h or zconf.h in the zlib library for more information.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Configuring for Medium Model
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Libpng's support for medium model has been tested on most of the popular
compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
defined, and FAR gets defined to far in pngconf.h, and you should be
all set. Everything in the library (except for zlib's structure) is
expecting far data. You must use the typedefs with the p or pp on
the end for pointers (or at least look at them and be careful). Make
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
note that the rows of data are defined as png_bytepp, which is
an "unsigned char far * far *".
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Configuring for gui/windowing platforms:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
You will need to write new error and warning functions that use the GUI
interface, as described previously, and set them to be the error and
Imported from libpng-1.0.5s.tar
2000-02-18 19:48:52 +00:00
warning functions at the time that png_create_*_struct() is called,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
in order to have them available during the structure initialization.
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
They can be changed later via png_set_error_fn(). On some compilers,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
you may also have to change the memory allocators (png_malloc, etc.).
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Configuring for compiler xxx:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.4.0beta11.tar
2006-08-19 18:59:24 +00:00
All includes for libpng are in pngconf.h. If you need to add, change
Imported from libpng-1.4.0beta51.tar
2009-03-21 13:15:32 +00:00
or delete an include, this is the place to do it.
The includes that are not needed outside libpng are placed in pngpriv.h,
which is only used by the routines inside libpng itself.
The files in libpng proper only include pngpriv.h and png.h, which
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
%14%in turn includes pngconf.h.
in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
As of libpng-1.5.0, pngpriv.h also includes three other private header
files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
that previously appeared in the public headers.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Configuring zlib:
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
There are special functions to configure the compression. Perhaps the
most useful one changes the compression level, which currently uses
input compression values in the range 0 - 9. The library normally
uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests
have shown that for a large majority of images, compression values in
the range 3-6 compress nearly as well as higher levels, and do so much
faster. For online applications it may be desirable to have maximum speed
(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also
specify no compression (Z_NO_COMPRESSION = 0), but this would create
files larger than just storing the raw bitmap. You can specify the
compression level by calling:
[devel] Imported from libpng-1.5.2beta03.tar
2011-03-03 12:23:31 +00:00
#include zlib.h
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_level(png_ptr, level);
Another useful one is to reduce the memory level used by the library.
The memory level defaults to 8, but it can be lowered if you are
short on memory (running DOS, for example, where you only have 640K).
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
Note that the memory level does have an effect on compression; among
other things, lower levels will result in sections of incompressible
data being emitted in smaller stored blocks, with a correspondingly
larger relative overhead of up to 15% in the worst case.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Imported from libpng-1.5.2beta03.tar
2011-03-03 12:23:31 +00:00
#include zlib.h
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_mem_level(png_ptr, level);
The other functions are for configuring zlib. They are not recommended
for normal use and may result in writing an invalid PNG file. See
zlib.h for more information on what these mean.
[devel] Imported from libpng-1.5.2beta03.tar
2011-03-03 12:23:31 +00:00
#include zlib.h
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_strategy(png_ptr,
strategy);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_window_bits(png_ptr,
window_bits);
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_compression_method(png_ptr, method);
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
png_set_compression_buffer_size(png_ptr, size);
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
As of libpng version 1.5.4, additional APIs became
available to set these separately for non-IDAT
compressed chunks such as zTXt, iTXt, and iCCP:
#include zlib.h
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
#if PNG_LIBPNG_VER >= 10504
[devel] Minor documentation editing.
2011-07-26 17:03:11 +00:00
png_set_text_compression_level(png_ptr, level);
png_set_text_compression_mem_level(png_ptr, level);
png_set_text_compression_strategy(png_ptr,
strategy);
png_set_text_compression_window_bits(png_ptr,
window_bits);
png_set_text_compression_method(png_ptr, method);
#endif
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Controlling row filtering
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
If you want to control whether libpng uses filtering or not, which
filters are used, and how it goes about picking row filters, you
can call one of these functions. The selection and configuration
of row filters can have a significant impact on the size and
encoding speed and a somewhat lesser impact on the decoding speed
of an image. Filtering is enabled by default for RGB and grayscale
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
images (with and without alpha), but not for paletted images nor
for any images with bit depths less than 8 bits/pixel.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The 'method' parameter sets the main filtering method, which is
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
currently only '0' in the PNG 1.2 specification. The 'filters'
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
parameter sets which filter(s), if any, should be used for each
scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
to turn filtering on and off, respectively.
Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
Imported from libpng-1.0.6i.tar
2000-05-01 14:31:54 +00:00
ORed together with '|' to specify one or more filters to use.
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
These filters are described in more detail in the PNG specification.
If you intend to change the filter type during the course of writing
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
the image, you should start with flags set for all of the filters
you intend to use so that libpng can initialize its internal
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
structures appropriately for all of the filter types. (Note that this
means the first row must always be adaptively filtered, because libpng
currently does not allocate the filter buffers until png_write_row()
is called for the first time.)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
filters = PNG_FILTER_NONE | PNG_FILTER_SUB
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
PNG_FILTER_UP | PNG_FILTER_AVG |
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
PNG_FILTER_PAETH | PNG_ALL_FILTERS;
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
filters);
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
The second parameter can also be
PNG_INTRAPIXEL_DIFFERENCING if you are
writing a PNG to be embedded in a MNG
datastream. This parameter must be the
same as the value of filter_method used
in png_set_IHDR().
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
It is also possible to influence how libpng chooses from among the
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
available filters. This is done in one or both of two ways - by
telling it how important it is to keep the same filter for successive
rows, and by telling it the relative computational costs of the filters.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
double weights[3] = {1.5, 1.3, 1.1},
costs[PNG_FILTER_VALUE_LAST] =
{1.0, 1.3, 1.3, 1.5, 1.7};
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
png_set_filter_heuristics(png_ptr,
PNG_FILTER_HEURISTIC_WEIGHTED, 3,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
weights, costs);
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
The weights are multiplying factors that indicate to libpng that the
row filter should be the same for successive rows unless another row filter
is that many times better than the previous filter. In the above example,
if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
"sum of absolute differences" 1.5 x 1.3 times higher than other filters
and still be chosen, while the NONE filter could have a sum 1.1 times
higher than other filters and still be chosen. Unspecified weights are
taken to be 1.0, and the specified weights should probably be declining
like those above in order to emphasize recent filters over older filters.
The filter costs specify for each filter type a relative decoding cost
to be considered when selecting row filters. This means that filters
with higher costs are less likely to be chosen over filters with lower
costs, unless their "sum of absolute differences" is that much smaller.
The costs do not necessarily reflect the exact computational speeds of
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
the various filters, since this would unduly influence the final image
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
size.
Note that the numbers above were invented purely for this example and
are given only to help explain the function usage. Little testing has
been done to find optimum values for either the costs or the weights.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Removing unwanted object code
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
There are a bunch of #define's in pngconf.h that control what parts of
libpng are compiled. All the defines end in _SUPPORTED. If you are
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
never going to use a capability, you can change the #define to #undef
before recompiling libpng and save yourself code and data space, or
you can turn off individual capabilities with defines that begin with
PNG_NO_.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
You can also turn all of the transforms and ancillary chunk capabilities
Imported from libpng-1.0.6g.tar
2000-04-24 04:14:02 +00:00
off en masse with compiler directives that define
Imported from libpng-1.0.1c.tar
1998-05-09 15:02:29 +00:00
PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
or all four,
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
along with directives to turn on any of the capabilities that you do
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
transformations but still leave the library fully capable of reading
and writing PNG files with all known public chunks. Use of the
PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
that is incapable of reading or writing ancillary chunks. If you are
not using the progressive reading capability, you can turn that off
with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
capability, which you'll still have).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
All the reading and writing specific code are in separate files, so the
linker should only grab the files it needs. However, if you want to
make sure, or if you are building a stand alone library, all the
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
reading files start with "pngr" and all the writing files start with "pngw".
The files that don't match either (like png.c, pngtrans.c, etc.)
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
are used for both reading and writing, and always need to be included.
The progressive reader is in pngpread.c
If you are creating or distributing a dynamically linked library (a .so
or DLL file), you should not remove or disable any parts of the library,
as this will cause applications linked with different versions of the
library to fail if they call functions not available in your library.
The size of the library itself should not be an issue, because only
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
those sections that are actually used will be loaded into memory.
Imported from libpng-1.0.5q.tar
2000-02-05 05:40:16 +00:00
.SS Requesting debug printout
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
The macro definition PNG_DEBUG can be used to request debugging
printout. Set it to an integer value in the range 0 to 3. Higher
numbers result in increasing amounts of debugging information. The
information is printed to the "stderr" file, unless another file
name is specified in the PNG_DEBUG_FILE macro definition.
When PNG_DEBUG > 0, the following functions (macros) become available:
png_debug(level, message)
png_debug1(level, message, p1)
png_debug2(level, message, p1, p2)
in which "level" is compared to PNG_DEBUG to decide whether to print
the message, "message" is the formatted string to be printed,
and p1 and p2 are parameters that are to be embedded in the string
according to printf-style formatting directives. For example,
[libpng16] Imported from libpng-1.6.3beta08.tar
2013-06-18 17:55:37 +00:00
png_debug1(2, "foo=%d", foo);
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
is expanded to
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
if (PNG_DEBUG > 2)
[libpng16] Imported from libpng-1.6.3beta08.tar
2013-06-18 17:55:37 +00:00
fprintf(PNG_DEBUG_FILE, "foo=%d\en", foo);
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
can still use PNG_DEBUG to control your own debugging:
#ifdef PNG_DEBUG
fprintf(stderr, ...
#endif
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
having level = 0 will be printed. There aren't any such statements in
this version of libpng, but if you insert some they will be printed.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
.SS Prepending a prefix to exported symbols
Starting with libpng-1.6.0, you can configure libpng (when using the
"configure" script) to prefix all exported symbols by means of the
configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
string beginning with a letter and containing only uppercase
and lowercase letters, digits, and the underscore (i.e., a C language
identifier). This creates a set of macros in pnglibconf.h, so this is
transparent to applications; their function calls get transformed by
the macros to use the modified names.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH VII. MNG support
Imported from libpng-1.0.9beta5.tar
2000-12-15 14:54:42 +00:00
The MNG specification (available at http://www.libpng.org/pub/mng) allows
certain extensions to PNG for PNG images that are embedded in MNG datastreams.
Libpng can support some of these extensions. To enable them, use the
png_permit_mng_features() function:
feature_set = png_permit_mng_features(png_ptr, mask)
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
mask is a png_uint_32 containing the bitwise OR of the
Imported from libpng-1.0.9beta5.tar
2000-12-15 14:54:42 +00:00
features you want to enable. These include
PNG_FLAG_MNG_EMPTY_PLTE
PNG_FLAG_MNG_FILTER_64
PNG_ALL_MNG_FEATURES
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
Imported from libpng-1.4.0beta12.tar
2006-10-19 14:37:56 +00:00
feature_set is a png_uint_32 that is the bitwise AND of
Imported from libpng-1.0.9beta5.tar
2000-12-15 14:54:42 +00:00
your mask with the set of MNG features that is
supported by the version of libpng that you are using.
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
It is an error to use this function when reading or writing a standalone
PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped
Imported from libpng-1.0.9rc1.tar
2000-12-23 20:27:39 +00:00
in a MNG datastream. As a minimum, it must have the MNG 8-byte signature
and the MHDR and MEND chunks. Libpng does not provide support for these
or any other MNG chunks; your application must provide its own support for
them. You may wish to consider using libmng (available at
http://www.libmng.com) instead.
Imported from libpng-1.0.9beta6.tar
2000-12-18 15:33:57 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH VIII. Changes to Libpng from version 0.88
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
It should be noted that versions of libpng later than 0.96 are not
distributed by the original libpng author, Guy Schalnat, nor by
Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
distributed versions 0.89 through 0.96, but rather by another member
of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are
still alive and well, but they have moved on to other things.
The old libpng functions png_read_init(), png_write_init(),
Imported from libpng-1.2.0beta3.tar
2001-05-18 09:54:50 +00:00
png_info_init(), png_read_destroy(), and png_write_destroy() have been
Imported from libpng-1.0.7beta11.tar
2000-05-06 19:09:57 +00:00
moved to PNG_INTERNAL in version 0.95 to discourage their use. These
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
functions will be removed from libpng version 1.4.0.
Imported from libpng-1.0.7beta11.tar
2000-05-06 19:09:57 +00:00
The preferred method of creating and initializing the libpng structures is
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
via the png_create_read_struct(), png_create_write_struct(), and
png_create_info_struct() because they isolate the size of the structures
from the application, allow version error checking, and also allow the
use of custom error handling routines during the initialization, which
the old functions do not. The functions png_read_destroy() and
png_write_destroy() do not actually free the memory that libpng
allocated for these structs, but just reset the data structures, so they
can be used instead of png_destroy_read_struct() and
png_destroy_write_struct() if you feel there is too much system overhead
allocating and freeing the png_struct for each image read.
Setting the error callbacks via png_set_message_fn() before
png_read_init() as was suggested in libpng-0.88 is no longer supported
Imported from libpng-1.0.2a.tar
1998-12-29 17:47:59 +00:00
because this caused applications that do not use custom error functions
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
to fail if the png_ptr was not initialized to zero. It is still possible
to set the error callbacks AFTER png_read_init(), or to change them with
Imported from libpng-1.0.7beta11.tar
2000-05-06 19:09:57 +00:00
png_set_error_fn(), which is essentially the same function, but with a new
name to force compilation errors with applications that try to use the old
method.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
Starting with version 1.0.7, you can find out which version of the library
you are using at run-time:
png_uint_32 libpng_vn = png_access_version_number();
The number libpng_vn is constructed from the major version, minor
version with leading zero, and release number with leading zero,
(e.g., libpng_vn for version 1.0.7 is 10007).
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
Note that this function does not take a png_ptr, so you can call it
before you've created one.
Imported from libpng-1.0.7beta12.tar
2000-05-12 11:19:53 +00:00
You can also check which version of png.h you used when compiling your
application:
png_uint_32 application_vn = PNG_LIBPNG_VER;
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH IX. Changes to Libpng from version 1.0.x to 1.2.x
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
Support for user memory management was enabled by default. To
accomplish this, the functions png_create_read_struct_2(),
png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
png_malloc_default(), and png_free_default() were added.
[devel] Imported from libpng-1.4.0beta90.tar
2009-11-02 13:32:00 +00:00
Support for the iTXt chunk has been enabled by default as of
version 1.2.41.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
Support for certain MNG features was enabled.
Support for numbered error messages was added. However, we never got
around to actually numbering the error messages. The function
png_set_strip_error_numbers() was added (Note: the prototype for this
function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
builds of libpng-1.2.15. It was restored in libpng-1.2.36).
The png_malloc_warn() function was added at libpng-1.2.3. This issues
a png_warning and returns NULL instead of aborting when it fails to
acquire the requested memory allocation.
Support for setting user limits on image width and height was enabled
by default. The functions png_set_user_limits(), png_get_user_width_max(),
and png_get_user_height_max() were added at libpng-1.2.6.
The png_set_add_alpha() function was added at libpng-1.2.7.
The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
deprecated.
A number of macro definitions in support of runtime selection of
assembler code features (especially Intel MMX code support) were
added at libpng-1.2.0:
PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
PNG_ASM_FLAG_MMX_READ_INTERLACE
PNG_ASM_FLAG_MMX_READ_FILTER_SUB
PNG_ASM_FLAG_MMX_READ_FILTER_UP
PNG_ASM_FLAG_MMX_READ_FILTER_AVG
PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
PNG_ASM_FLAGS_INITIALIZED
PNG_MMX_READ_FLAGS
PNG_MMX_FLAGS
PNG_MMX_WRITE_FLAGS
PNG_MMX_FLAGS
We added the following functions in support of runtime
selection of assembler code features:
png_get_mmx_flagmask()
png_set_mmx_thresholds()
png_get_asm_flags()
png_get_mmx_bitdepth_threshold()
png_get_mmx_rowbytes_threshold()
png_set_asm_flags()
We replaced all of these functions with simple stubs in libpng-1.2.20,
when the Intel assembler code was removed due to a licensing issue.
[devel] Updated documentation about newly deprecated macros.
2009-08-31 18:32:46 +00:00
These macros are deprecated:
PNG_READ_TRANSFORMS_NOT_SUPPORTED
PNG_PROGRESSIVE_READ_NOT_SUPPORTED
PNG_NO_SEQUENTIAL_READ_SUPPORTED
PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
They have been replaced, respectively, by:
PNG_NO_READ_TRANSFORMS
PNG_NO_PROGRESSIVE_READ
PNG_NO_SEQUENTIAL_READ
PNG_NO_WRITE_TRANSFORMS
PNG_NO_READ_ANCILLARY_CHUNKS
PNG_NO_WRITE_ANCILLARY_CHUNKS
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been
deprecated since libpng-1.0.16 and libpng-1.2.6.
The function
png_check_sig(sig, num)
was replaced with
!png_sig_cmp(sig, 0, num)
It has been deprecated since libpng-0.90.
The function
png_set_gray_1_2_4_to_8()
which also expands tRNS to alpha was replaced with
png_set_expand_gray_1_2_4_to_8()
which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
[devel] Show differences between 1.2.40 and 1.4.0 instead of between 1.2.41 and 1.4.0 in documentation.
2009-11-05 01:01:54 +00:00
Private libpng prototypes and macro definitions were moved from
png.h and pngconf.h into a new pngpriv.h header file.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
Functions png_set_benign_errors(), png_benign_error(), and
png_chunk_benign_error() were added.
Support for setting the maximum amount of memory that the application
will allocate for reading chunks was added, as a security measure.
The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
were added to the library.
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
We implemented support for I/O states by adding png_ptr member io_state
and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
[devel] Imported from libpng-1.4.0beta87.tar
2009-10-30 04:32:44 +00:00
We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
input transforms.
Checking for and reporting of errors in the IHDR chunk is more thorough.
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
Support for global arrays was removed, to improve thread safety.
Some obsolete/deprecated macros and functions have been removed.
Typecasted NULL definitions such as
#define png_voidp_NULL (png_voidp)NULL
were eliminated. If you used these in your application, just use
NULL instead.
The png_struct and info_struct members "trans" and "trans_values" were
changed to "trans_alpha" and "trans_color", respectively.
The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
were removed.
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
The PNG_1_0_X and PNG_1_2_X macros were eliminated.
[devel] Imported from libpng-1.4.0beta87.tar
2009-10-30 04:32:44 +00:00
The PNG_LEGACY_SUPPORTED macro was eliminated.
Many WIN32_WCE #ifdefs were removed.
The functions png_read_init(info_ptr), png_write_init(info_ptr),
png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
have been removed. They have been deprecated since libpng-0.95.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
The png_permit_empty_plte() was removed. It has been deprecated
since libpng-1.0.9. Use png_permit_mng_features() instead.
We removed the obsolete stub functions png_get_mmx_flagmask(),
png_set_mmx_thresholds(), png_get_asm_flags(),
png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
png_set_asm_flags(), and png_mmx_supported()
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
We removed the obsolete png_check_sig(), png_memcpy_check(), and
[devel] Update documentation
2010-07-30 00:09:18 +00:00
png_memset_check() functions. Instead use !png_sig_cmp(), memcpy(),
and memset(), respectively.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
The function png_set_gray_1_2_4_to_8() was removed. It has been
deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
png_set_expand_gray_1_2_4_to_8() because the former function also
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
expanded any tRNS chunk to an alpha channel.
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
[devel] Added a remark about png_get_uint_16 in the libpng-manual.txt and libpng.3
2010-11-25 13:16:29 +00:00
Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
were added and are used by default instead of the corresponding
functions. Unfortunately,
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
[devel] Added a remark about png_get_uint_16 in the libpng-manual.txt and libpng.3
2010-11-25 13:16:29 +00:00
function) incorrectly returned a value of type png_uint_32.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
We changed the prototype for png_malloc() from
png_malloc(png_structp png_ptr, png_uint_32 size)
to
png_malloc(png_structp png_ptr, png_alloc_size_t size)
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
This also applies to the prototype for the user replacement malloc_fn().
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
The png_calloc() function was added and is used in place of
[devel] Update documentation
2010-07-30 00:09:18 +00:00
of "png_malloc(); memset();" except in the case in png_read_png()
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
where the array consists of pointers; in this case a "for" loop is used
after the png_malloc() to set the pointers to NULL, to give robust.
behavior in case the application runs out of memory part-way through
the process.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
We changed the prototypes of png_get_compression_buffer_size() and
png_set_compression_buffer_size() to work with png_size_t instead of
png_uint_32.
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
Support for numbered error messages was removed by default, since we
never got around to actually numbering the error messages. The function
png_set_strip_error_numbers() was removed from the library by default.
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
The png_zalloc() and png_zfree() functions are no longer exported.
[devel] Updated documentation about libpng-1.2 to 1.4 differences.
2009-12-30 14:37:29 +00:00
The png_zalloc() function no longer zeroes out the memory that it
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
allocates. Applications that called png_zalloc(png_ptr, number, size)
can call png_calloc(png_ptr, number*size) instead, and can call
png_free() instead of png_zfree().
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
Support for dithering was disabled by default in libpng-1.4.0, because
[devel] Imported from libpng-1.5.3beta03.tar
2011-04-17 00:40:23 +00:00
it has not been well tested and doesn't actually "dither".
The code was not
[devel] Imported from libpng-1.5.0beta17.tar
2010-04-17 00:27:08 +00:00
removed, however, and could be enabled by building libpng with
PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support
was reenabled, but the function was renamed png_set_quantize() to
reflect more accurately what it actually does. At the same time,
the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
was renamed to PNG_READ_QUANTIZE_SUPPORTED.
[devel] Document the fact that png_set_dither() is no longer supported.
2010-04-14 03:11:06 +00:00
Imported from libpng-1.4.0beta52.tar
2009-03-28 00:30:10 +00:00
We removed the trailing '.' from the warning and error messages.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XI. Changes to Libpng from version 1.4.x to 1.5.x
[devel] Added a remark about png_get_uint_16 in the libpng-manual.txt and libpng.3
2010-11-25 13:16:29 +00:00
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
[devel] Added a remark about png_get_uint_16 in the libpng-manual.txt and libpng.3
2010-11-25 13:16:29 +00:00
function) incorrectly returned a value of type png_uint_32.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Checking for invalid palette index on read or write was added at libpng
1.5.10. When an invalid index is found, libpng issues a benign error.
This is enabled by default because this condition is an error according
to the PNG specification, Clause 11.3.2, but the error can be ignored in
each png_ptr with
png_set_check_for_invalid_index(png_ptr, allowed);
allowed - one of
0: disable benign error (accept the
invalid data without warning).
1: enable benign error (treat the
invalid data as an error or a
warning).
If the error is ignored, or if png_benign_error() treats it as a warning,
any invalid pixels are decoded as opaque black by the decoder and written
as-is by the encoder.
Retrieving the maximum palette index found was added at libpng-1.5.15.
This statement must appear after png_read_png() or png_read_image() while
reading, and after png_write_png() or png_write_image() while writing.
int max_palette = png_get_palette_max(png_ptr, info_ptr);
This will return the maximum palette index found in the image, or "-1" if
the palette was not checked, or "0" if no palette was found. Note that this
does not account for any palette index used by ancillary chunks such as the
bKGD chunk; you must check those separately to determine the maximum
palette index actually used.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
A. Changes that affect users of libpng
There are no substantial API changes between the non-deprecated parts of
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
members of the main libpng control structures, png_struct and png_info,
deprecated in earlier versions of libpng, has been completely removed from
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
libpng 1.5.
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
We no longer include zlib.h in png.h. The include statement has been moved
to pngstruct.h, where it is not accessible by applications. Applications that
need access to information in zlib.h will need to add the '#include "zlib.h"'
directive. It does not matter whether this is placed prior to or after
[devel] Mentioned in the documentation that applications must #include "zlib.h" if they need access to anything in zlib.h, and that a number of macros such as png_memset() are no longer accessible by applications.
2011-01-16 01:25:34 +00:00
the '"#include png.h"' directive.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
and were removed.
We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
macros into a private header file (pngpriv.h) that is not accessible to
applications.
[devel] Mentioned in the documentation that applications must #include "zlib.h" if they need access to anything in zlib.h, and that a number of macros such as png_memset() are no longer accessible by applications.
2011-01-16 01:25:34 +00:00
[devel] Added a note in the manual that the type of the iCCP profile changed from png_charpp to png_bytepp in png_get_iCCP(). This change happened in version 1.5.0beta36 but is not noted in the CHANGES. Also, revised the "synopsis" for png_get_iCCP() in libpng.3 accordingly.
2011-01-08 16:42:01 +00:00
In png_get_iCCP, the type of "profile" was changed from png_charpp
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
[devel] Added a note in the manual that the type of the iCCP profile changed from png_charpp to png_bytepp in png_get_iCCP(). This change happened in version 1.5.0beta36 but is not noted in the CHANGES. Also, revised the "synopsis" for png_get_iCCP() in libpng.3 accordingly.
2011-01-08 16:42:01 +00:00
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
There are changes of form in png.h, including new and changed macros to
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
declare parts of the API. Some API functions with arguments that are
pointers to data not modified within the function have been corrected to
declare these arguments with PNG_CONST.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
Much of the internal use of C macros to control the library build has also
changed and some of this is visible in the exported header files, in
particular the use of macros to control data and API elements visible
during application compilation may require significant revision to
application code. (It is extremely rare for an application to do this.)
Any program that compiled against libpng 1.4 and did not use deprecated
features or access internal library structures should compile and work
[devel] Imported from libpng-1.5.2beta02.tar
2011-02-19 21:50:17 +00:00
against libpng 1.5, except for the change in the prototype for
png_get_iCCP() and png_set_iCCP() API functions mentioned above.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
[devel] Imported from libpng-1.5.0beta58.tar
2010-12-19 22:44:22 +00:00
libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
interlaced images. The macros return the number of rows and columns in
each pass and information that can be used to de-interlace and (if
absolutely necessary) interlace an image.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
libpng 1.5.0 adds an API png_longjmp(png_ptr, value). This API calls
[devel] Imported from libpng-1.5.2beta02.tar
2011-02-19 21:50:17 +00:00
the application-provided png_longjmp_ptr on the internal, but application
[devel] Bump to version libpng-1.5.3beta04
2011-04-27 19:58:06 +00:00
initialized, longjmp buffer. It is provided as a convenience to avoid
the need to use the png_jmpbuf macro, which had the unnecessary side
effect of resetting the internal png_longjmp_ptr value.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
libpng 1.5.0 includes a complete fixed point API. By default this is
present along with the corresponding floating point API. In general the
fixed point API is faster and smaller than the floating point one because
the PNG file format used fixed point, not floating point. This applies
even if the library uses floating point in internal calculations. A new
macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
uses floating point arithmetic (the default) or fixed point arithmetic
internally for performance critical calculations such as gamma correction.
[devel] Mentioned in the documentation that applications must #include "zlib.h" if they need access to anything in zlib.h, and that a number of macros such as png_memset() are no longer accessible by applications.
2011-01-16 01:25:34 +00:00
In some cases, the gamma calculations may produce slightly different
results. This has changed the results in png_rgb_to_gray and in alpha
composition (png_set_background for example). This applies even if the
original image was already linear (gamma == 1.0) and, therefore, it is
not necessary to linearize the image. This is because libpng has *not*
been changed to optimize that case correctly, yet.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
Fixed point support for the sCAL chunk comes with an important caveat;
the sCAL specification uses a decimal encoding of floating point values
and the accuracy of PNG fixed point values is insufficient for
representation of these values. Consequently a "string" API
(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
arbitrary sCAL chunks in the absence of either the floating point API or
internal floating point calculations.
Applications no longer need to include the optional distribution header
file pngusr.h or define the corresponding macros during application
build in order to see the correct variant of the libpng API. From 1.5.0
application code can check for the corresponding _SUPPORTED macro:
#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
/* code that uses the inch conversion APIs. */
#endif
This macro will only be defined if the inch conversion functions have been
compiled into libpng. The full set of macros, and whether or not support
has been compiled in, are available in the header file pnglibconf.h.
This header file is specific to the libpng build. Notice that prior to
1.5.0 the _SUPPORTED macros would always have the default definition unless
reset by pngusr.h or by explicit settings on the compiler command line.
These settings may produce compiler warnings or errors in 1.5.0 because
of macro redefinition.
[devel] Trim trailing blanks from sources and manual
2011-02-12 15:49:07 +00:00
From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
function) incorrectly returned a value of type png_uint_32. libpng 1.5.0
is consistent with the implementation in 1.4.5 and 1.2.x (where the macro
did not exist.)
Applications can now choose whether to use these macros or to call the
corresponding function by defining PNG_USE_READ_MACROS or
PNG_NO_USE_READ_MACROS before including png.h. Notice that this is
only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
[libpng15] Imported from libpng-1.5.5beta07.tar
2011-09-08 17:21:42 +00:00
will lead to a link failure.
[devel] Fixed a small typo in the manual.
2011-01-06 13:07:06 +00:00
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
[devel] Updated manual about the new API additions
2011-04-01 05:16:50 +00:00
when compressing the IDAT data and textual data such as zTXt and iCCP.
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
[devel] Updated manual about the new API additions
2011-04-01 05:16:50 +00:00
We added five png_set_text_*() functions for setting the parameters to
use with textual data.
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
[devel] Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is wrong (high by one) 25% of the time. Dividing by 257 with rounding is wrong in 128 out of 65536 cases. Getting the right answer all the time without division is easy.
2011-06-11 04:24:58 +00:00
option was off by default, and slightly inaccurate scaling occurred.
[devel] Imported from libpng-1.5.4beta05.tar
2011-06-18 01:38:24 +00:00
This option can no longer be turned off, and the choice of accurate
or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
API for accurate scaling or the old png_set_strip_16_to_8() API for simple
chopping.
[devel] Imported from libpng-1.5.3beta11.tar
2011-06-11 19:22:22 +00:00
[devel] Added information about "chop_16" to the manual.
2011-06-15 18:21:01 +00:00
Prior to libpng-1.5.4, the png_set_user_limits() function could only be
[devel] Imported from libpng-1.5.3beta11.tar
2011-06-11 19:22:22 +00:00
used to reduce the width and height limits from the value of
PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
that it could be used to override them. Now this function will reduce or
increase the limits.
[devel] Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is wrong (high by one) 25% of the time. Dividing by 257 with rounding is wrong in 128 out of 65536 cases. Getting the right answer all the time without division is easy.
2011-06-11 04:24:58 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Starting in libpng-1.5.10, the user limits can be set en masse with the
configuration option PNG_SAFE_LIMITS_SUPPORTED. If this option is enabled,
a set of "safe" limits is applied in pngpriv.h. These can be overridden by
application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
and/or png_set_user_malloc_max() that increase or decrease the limits. Also,
in libpng-1.5.10 the default width and height limits were increased
from 1,000,000 to 0x7ffffff (i.e., made unlimited). Therefore, the
limits are now
default safe
png_user_width_max 0x7fffffff 1,000,000
png_user_height_max 0x7fffffff 1,000,000
png_user_chunk_cache_max 0 (unlimited) 128
png_user_chunk_malloc_max 0 (unlimited) 8,000,000
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
B. Changes to the build and configuration of libpng
Details of internal changes to the library code can be found in the CHANGES
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
file and in the GIT repository logs. These will be of no concern to the vast
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
majority of library users or builders; however, the few who configure libpng
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
to a non-default feature set may need to change how this is done.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
There should be no need for library builders to alter build scripts if
these use the distributed build support - configure or the makefiles -
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
however, users of the makefiles may care to update their build scripts
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
to build pnglibconf.h where the corresponding makefile does not do so.
Building libpng with a non-default configuration has changed completely.
The old method using pngusr.h should still work correctly even though the
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
way pngusr.h is used in the build has been changed; however, library
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
builders will probably want to examine the changes to take advantage of
new capabilities and to simplify their build system.
B.1 Specific changes to library configuration capabilities
The library now supports a complete fixed point implementation and can
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
thus be used on systems that have no floating point support or very
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
limited or slow support. Previously gamma correction, an essential part
of complete PNG support, required reasonably fast floating point.
As part of this the choice of internal implementation has been made
independent of the choice of fixed versus floating point APIs and all the
missing fixed point APIs have been implemented.
The exact mechanism used to control attributes of API functions has
changed. A single set of operating system independent macro definitions
is used and operating system specific directives are defined in
pnglibconf.h
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
As part of this the mechanism used to choose procedure call standards on
those systems that allow a choice has been changed. At present this only
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
running on Intel processors. As before, PNGAPI is defined where required
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
to control the exported API functions; however, two new macros, PNGCBAPI
and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
(PNGCAPI) for functions that must match a C library prototype (currently
only png_longjmp_ptr, which must match the C longjmp function.) The new
approach is documented in pngconf.h
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
Despite these changes, libpng 1.5.0 only supports the native C function
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
calling standard on those platforms tested so far (__cdecl on Microsoft
Windows). This is because the support requirements for alternative
calling conventions seem to no longer exist. Developers who find it
necessary to set PNG_API_RULE to 1 should advise the mailing list
(png-mng-implement) of this and library builders who use Openwatcom and
therefore set PNG_API_RULE to 2 should also contact the mailing list.
A new test program, pngvalid, is provided in addition to pngtest.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
pngvalid validates the arithmetic accuracy of the gamma correction
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
calculations and includes a number of validations of the file format.
A subset of the full range of tests is run when "make check" is done
(in the 'configure' build.) pngvalid also allows total allocated memory
usage to be evaluated and performs additional memory overwrite validation.
Many changes to individual feature macros have been made. The following
are the changes most likely to be noticed by library builders who
configure libpng:
1) All feature macros now have consistent naming:
#define PNG_NO_feature turns the feature off
#define PNG_feature_SUPPORTED turns the feature on
pnglibconf.h contains one line for each feature macro which is either:
#define PNG_feature_SUPPORTED
if the feature is supported or:
/*#undef PNG_feature_SUPPORTED*/
if it is not. Library code consistently checks for the 'SUPPORTED' macro.
[devel] Revised manual paragraph about use of 'NO' macros.
2011-07-12 15:28:02 +00:00
It does not, and libpng applications should not, check for the 'NO' macro
which will not normally be defined even if the feature is not supported.
The 'NO' macros are only used internally for setting or not setting the
corresponding 'SUPPORTED' macros.
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
Compatibility with the old names is provided as follows:
PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
And the following definitions disable the corresponding feature:
PNG_SETJMP_NOT_SUPPORTED disables SETJMP
PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
Library builders should remove use of the above, inconsistent, names.
2) Warning and error message formatting was previously conditional on
the STDIO feature. The library has been changed to use the
CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
the library no longer uses the printf(3) functions, even though the
default read/write implementations use (FILE) style stdio.h functions.
3) Three feature macros now control the fixed/floating point decisions:
PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
practice these are normally required internally anyway (because the PNG
file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
merely stops the function from being exported.
PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
point implementation or the fixed point one. Typically the fixed point
implementation is larger and slower than the floating point implementation
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
on a system that supports floating point; however, it may be faster on a
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
system which lacks floating point hardware and therefore uses a software
emulation.
4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the
functions to read and write ints to be disabled independently of
PNG_USE_READ_MACROS, which allows libpng to be built with the functions
even though the default is to use the macros - this allows applications
to choose at app buildtime whether or not to use macros (previously
impossible because the functions weren't in the default build.)
B.2 Changes to the configuration mechanism
Prior to libpng-1.5.0 library builders who needed to configure libpng
had either to modify the exported pngconf.h header file to add system
specific configuration or had to write feature selection macros into
pngusr.h and cause this to be included into pngconf.h by defining
PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
application built without PNG_USER_CONFIG defined would see the
unmodified, default, libpng API and thus would probably fail to link.
These mechanisms still work in the configure build and in any makefile
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
build that builds pnglibconf.h, although the feature selection macros
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
have changed somewhat as described above. In 1.5.0, however, pngusr.h is
processed only once, when the exported header file pnglibconf.h is built.
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
build of pnglibconf.h and it is never included in an application build.
The rarely used alternative of adding a list of feature macros to the
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
CFLAGS setting in the build also still works; however, the macros will be
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
copied to pnglibconf.h and this may produce macro redefinition warnings
when the individual C files are compiled.
All configuration now only works if pnglibconf.h is built from
scripts/pnglibconf.dfa. This requires the program awk. Brian Kernighan
(the original author of awk) maintains C source code of that awk and this
and all known later implementations (often called by subtly different
names - nawk and gawk for example) are adequate to build pnglibconf.h.
The Sun Microsystems (now Oracle) program 'awk' is an earlier version
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
and does not work; this may also apply to other systems that have a
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
functioning awk called 'nawk'.
Configuration options are now documented in scripts/pnglibconf.dfa. This
file also includes dependency information that ensures a configuration is
consistent; that is, if a feature is switched off dependent features are
also removed. As a recommended alternative to using feature macros in
pngusr.h a system builder may also define equivalent options in pngusr.dfa
(or, indeed, any file) and add that to the configuration by setting
DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate
how to do this, and a case where pngusr.h is still required.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XII. Changes to Libpng from version 1.5.x to 1.6.x
A "simplified API" has been added (see documentation in png.h and a simple
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
example in contrib/examples/pngtopng.c). The new publicly visible API
includes the following:
macros:
PNG_FORMAT_*
PNG_IMAGE_*
structures:
png_control
png_image
read functions
png_image_begin_read_from_file()
png_image_begin_read_from_stdio()
png_image_begin_read_from_memory()
png_image_finish_read()
png_image_free()
write functions
png_image_write_to_file()
png_image_write_to_stdio()
Starting with libpng-1.6.0, you can configure libpng to prefix all exported
symbols, using the PNG_PREFIX macro.
[libpng16] Imported from libpng-1.6.0beta08.tar
2012-02-01 04:21:32 +00:00
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
We no longer include string.h in png.h. The include statement has been moved
to pngpriv.h, where it is not accessible by applications. Applications that
[libpng16] Expanded manual paragraph about writing private chunks, particularly about the need to call png_set_keep_unknown_chunks() when writing them.
2013-04-27 23:03:03 +00:00
need access to information in string.h must add an '#include <string.h>'
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
directive. It does not matter whether this is placed prior to or after
[libpng16] Revise man page to demonstrate dealing with unknown chunk handling in libpng.1.5.x and with bugs in libpng-1.4.x and earlier.
2013-04-29 01:48:37 +00:00
the '#include "png.h"' directive.
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
The following API are now DEPRECATED:
png_info_init_3()
png_convert_to_rfc1123() which has been replaced
with png_convert_to_rfc1123_buffer()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_data_freer()
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
png_malloc_default()
png_free_default()
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
png_reset_zstream()
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The following have been removed:
[libpng16] Began a manual section about libpng15 to libpng16 differences.
2011-12-22 20:23:37 +00:00
png_get_io_chunk_name(), which has been replaced
with png_get_io_chunk_type(). The new
function returns a 32-bit integer instead of
a string.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
png_memset() macros are no longer used in the libpng sources and
have been removed. These had already been made invisible to applications
(i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
The signatures of many exported functions were changed, such that
png_structp became png_structrp or png_const_structrp
png_infop became png_inforp or png_const_inforp
where "rp" indicates a "restricted pointer".
Error detection in some chunks has improved; in particular the iCCP chunk
reader now does pretty complete validation of the basic format. Some bad
profiles that were previously accepted are now rejected, in particular the
[libpng16] Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
2013-04-01 03:55:55 +00:00
very old broken Microsoft/HP sRGB profile. The PNG spec requirement that
only grayscale profiles may appear in images with color type 0 or 4 and that
even if the image only contains gray pixels, only RGB profiles may appear
in images with color type 2, 3, or 6, is now enforced. The sRGB chunk
is allowed to appear in images with any color type.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The library now issues an error if the application attempts to set a
transform after it calls png_read_update_info().
The library now issues a warning if both background processing and RGB to
gray are used when gamma correction happens. As with previous versions of
the library the results are numerically very incorrect in this case.
There are some minor arithmetic changes in some transforms such as
png_set_background(), that might be detected by certain regression tests.
Unknown chunk handling has been improved internally, without any API change.
This adds more correct option control of the unknown handling, corrects
a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
it possible to skip IDAT chunks in the sequential reader.
The machine-generated configure files are no longer included in branches
libpng16 and later of the GIT repository. They continue to be included
in the tarball releases, however.
[libpng16] Added documentation of the new png_get_palette_max() function.
2013-02-05 01:50:56 +00:00
[libpng16] Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt. Added information in the documentation about problems with and fixes for the bad CRC and bad iTXt chunk situations.
2013-05-09 00:46:10 +00:00
Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
to set the size of the sliding window for reading instead of using the default
32-kbyte sliding window size. It was discovered that there are hundreds of PNG
files in the wild that have incorrect CMF bytes that cause libpng to now issue
a "too far back" error and reject the file. Libpng-1.6.3 provides a way to
[libpng16] Imported from libpng-1.6.3beta05.tar
2013-05-09 03:04:02 +00:00
revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
32-kbyte sliding window), and provides a tool
(contrib/tools/png-fix-too-far-back) for optimizing the CMF bytes
correctly.
[libpng16] Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt. Added information in the documentation about problems with and fixes for the bad CRC and bad iTXt chunk situations.
2013-05-09 00:46:10 +00:00
Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
length, which resulted in PNG files that cannot be read beyond the bad iTXt
chunk. This error was fixed in libpng-1.6.3, and a tool (called
contrib/tools/png-fix-itxt) has been added to the libpng distribution.
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XIII. Detecting libpng
Imported from libpng-1.4.0beta62.tar
2009-06-02 18:45:15 +00:00
The png_get_io_ptr() function has been present since libpng-0.88, has never
changed, and is unaffected by conditional compilation macros. It is the
best choice for use in configure scripts for detecting the presence of any
[devel] Added high-level PNG_TRANSFORM_GRAY_TO_RGB transform.
2009-06-29 22:30:00 +00:00
libpng version since 0.88. In an autoconf "configure.in" you could use
AC_CHECK_LIB(png, png_get_io_ptr, ...
Imported from libpng-1.4.0beta62.tar
2009-06-02 18:45:15 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XV. Source code repository
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
Since about February 2009, version 1.2.34, libpng has been under "git" source
control. The git repository was built from old libpng-x.y.z.tar.gz files
going back to version 0.70. You can access the git repository (read only)
at
[libpng16] Updated the GIT URL in the manual.
2013-04-11 23:53:51 +00:00
git://git.code.sf.net/p/libpng/code
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
[libpng16] Updated the GIT URL in the manual.
2013-04-11 23:53:51 +00:00
or you can browse it with a web browser by selecting the "code" button at
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
[libpng16] Updated the GIT URL in the manual.
2013-04-11 23:53:51 +00:00
https://sourceforge.net/projects/libpng
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
Patches can be sent to glennrp at users.sourceforge.net or to
png-mng-implement at lists.sourceforge.net or you can upload them to
the libpng bug tracker at
http://libpng.sourceforge.net
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
We also accept patches built from the tar or zip distributions, and
simple verbal discriptions of bug fixes, reported either to the
[devel] Minor editing of the manual.
2011-07-12 15:13:32 +00:00
SourceForge bug tracker, to the png-mng-implement at lists.sf.net
mailing list, or directly to glennrp.
[devel] Updated manual synopses, fixed several typos, put paramter descriptions in proper order, applied libpng indentation style in code snippets.
2011-01-22 05:29:09 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XV. Coding style
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
Our coding style is similar to the "Allman" style, with curly
braces on separate lines:
if (condition)
{
action;
}
else if (another condition)
{
another action;
}
The braces can be omitted from simple one-line actions:
if (condition)
return (0);
We use 3-space indentation, except for continued statements which
are usually indented the same as the first line of the statement
plus four more spaces.
[devel] Imported from libpng-1.4.0beta84.tar
2009-09-30 20:11:49 +00:00
For macro definitions we use 2-space indentation, always leaving the "#"
in the first column.
#ifndef PNG_NO_FEATURE
# ifndef PNG_FEATURE_SUPPORTED
# define PNG_FEATURE_SUPPORTED
# endif
#endif
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
Comments appear with the leading "/*" at the same indentation as
the statement that follows the comment:
/* Single-line comment */
statement;
[devel] Imported from libpng-1.5.0beta11.tar
2010-03-06 20:51:54 +00:00
/* This is a multiple-line
* comment.
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
*/
statement;
[devel] Imported from libpng-1.5.0beta11.tar
2010-03-06 20:51:54 +00:00
Very short comments can be placed after the end of the statement
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
to which they pertain:
statement; /* comment */
We don't use C++ style ("//") comments. We have, however,
used them in the past in some now-abandoned MMX assembler
code.
[devel] Revise libpng.3 about calling png_set_IHDR() multiple times and about the order of color samples in the tRNS chunk.
2009-06-08 13:36:19 +00:00
Functions and their curly braces are not indented, and
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
exported functions are marked with PNGAPI:
/* This is a public function that is visible to
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
* application programmers. It does thus-and-so.
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
*/
void PNGAPI
png_exported_function(png_ptr, png_info, foo)
{
body;
}
[devel] Imported from libpng-1.4.0beta70.tar
2009-07-28 03:16:09 +00:00
The prototypes for all exported functions appear in png.h,
above the comment that says
/* Maintainer: Put new public prototypes here ... */
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
We mark all non-exported functions with "/* PRIVATE */"":
void /* PRIVATE */
png_non_exported_function(png_ptr, png_info, foo)
{
body;
}
[devel] Imported from libpng-1.4.0beta70.tar
2009-07-28 03:16:09 +00:00
The prototypes for non-exported functions (except for those in
[devel] Imported from libpng-1.4.0beta87.tar
2009-10-30 04:32:44 +00:00
pngtest) appear in
pngpriv.h
[devel] Imported from libpng-1.4.0beta70.tar
2009-07-28 03:16:09 +00:00
above the comment that says
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
/* Maintainer: Put new private prototypes here ^ */
We put a space after the "sizeof" operator and we omit the
optional parentheses around its argument when the argument
is an expression, not a type name, and we always enclose the
sizeof operator, with its argument, in parentheses:
(sizeof (png_uint_32))
(sizeof array)
Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
though it were a function.
[libpng16] Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros.
2012-08-10 23:08:02 +00:00
[devel] Added a request in the manual that applications do not use "png_" or "PNG_" to begin any of their own symbols.
2011-01-29 22:12:11 +00:00
To avoid polluting the global namespace, the names of all exported
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
functions and variables begin with "png_", and all publicly visible C
preprocessor macros begin with "PNG". We request that applications that
[devel] Added a request in the manual that applications do not use "png_" or "PNG_" to begin any of their own symbols.
2011-01-29 22:12:11 +00:00
use libpng *not* begin any of their own symbols with either of these strings.
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
We put a space after each comma and after each semicolon
[devel] Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt and libpng.3
2010-12-07 02:06:01 +00:00
in "for" statements, and we put spaces before and after each
[devel] Imported from libpng-1.5.0beta11.tar
2010-03-06 20:51:54 +00:00
C binary operator and after "for" or "while", and before
"?". We don't put a space between a typecast and the expression
being cast, nor do we put one between a function name and the
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
left parenthesis that follows it:
for (i = 2; i > 0; --i)
[devel] Imported from libpng-1.4.0beta81.tar
2009-09-23 16:36:28 +00:00
y[i] = a(x) + (int)b;
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
We prefer #ifdef and #ifndef to #if defined() and #if !defined()
when there is only one macro being tested. We always use parentheses
with "defined".
[devel] Imported from libpng-1.4.0beta63.tar
2009-06-16 02:56:14 +00:00
[libpng15] Add leading zero to some 1-digit hex constants (0xf -> 0x0f).
2011-10-27 21:17:24 +00:00
We prefer to express integers that are used as bit masks in hex format,
with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
We prefer to use underscores in variable names rather than camelCase, except
for a few type names that we inherit from zlib.h.
[devel] Imported from libpng-1.4.0beta81.tar
2009-09-23 16:36:28 +00:00
We do not use the TAB character for indentation in the C sources.
[devel] Imported from libpng-1.4.0rc02.tar
2009-12-20 21:14:57 +00:00
Lines do not exceed 80 characters.
[devel] Restored recent documentation changes.
2009-11-12 16:02:24 +00:00
Other rules can be inferred by inspecting the libpng source.
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
[libpng16] Describe new simplified API in the manual pages and cleaned up some indentation problems.
2012-01-11 20:00:52 +00:00
.SH XVI. Y2K Compliance in libpng
Bump version to libpng-1.4.0beta60
2009-05-16 12:25:42 +00:00
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
June 27, 2013
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
This is your unofficial assurance that libpng from version 0.71 and
[libpng16] Bump version to 1.6.3beta09
2013-06-18 18:23:54 +00:00
upward through 1.6.3beta09 are Y2K compliant. It is my belief that earlier
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
versions were also Y2K compliant.
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
Libpng only has two year fields. One is a 2-byte unsigned integer
that will hold years up to 65535. The other, which is deprecated,
holds the date in text format, and will hold years up to 9999.
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
The integer is
"png_uint_16 year" in png_time_struct.
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
The string is
"char time_buffer[29]" in png_struct. This is no longer used
in libpng-1.6.x and will be removed from libpng-1.7.0.
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
There are seven time-related functions:
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
png_convert_to_rfc_1123() in png.c
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
(formerly png_convert_to_rfc_1152() in error)
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
png_convert_from_struct_tm() in pngwrite.c, called
in pngwrite.c
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
png_convert_from_time_t() in pngwrite.c
png_get_tIME() in pngget.c
png_handle_tIME() in pngrutil.c, called in pngread.c
png_set_tIME() in pngset.c
png_write_tIME() in pngwutil.c, called in pngwrite.c
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
All appear to handle dates properly in a Y2K environment. The
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
png_convert_from_time_t() function calls gmtime() to convert from system
clock time, which returns (year - 1900), which we properly convert to
the full 4-digit year. There is a possibility that applications using
libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
function, or that they are incorrectly passing only a 2-digit year
instead of "year - 1900" into the png_convert_from_struct_tm() function,
but this is not under our control. The libpng documentation has always
stated that it works with 4-digit years, and the APIs have been
documented as such.
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
integer to hold the year, and can hold years as large as 65535.
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
zlib, upon which libpng depends, is also Y2K compliant. It contains
no date-related code.
Imported from libpng-1.0.3.tar
1999-01-14 04:06:39 +00:00
Glenn Randers-Pehrson
libpng maintainer
PNG Development Group
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
.SH NOTE
Note about libpng version numbers:
Due to various miscommunications, unforeseen code incompatibilities
and occasional factors outside the authors' control, version numbering
on the library has not always been consistent and straightforward.
The following table summarizes matters since version 0.89c, which was
the first widely used release:
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
source png.h png.h shared-lib
version string int version
------- ------ ----- ----------
0.89c ("beta 3") 0.89 89 1.0.89
0.90 ("beta 4") 0.90 90 0.90
0.95 ("beta 5") 0.95 95 0.95
0.96 ("beta 6") 0.96 96 0.96
0.97b ("beta 7") 1.00.97 97 1.0.1
0.97c 0.97 97 2.0.97
0.98 0.98 98 2.0.98
0.99 0.99 98 2.0.99
0.99a-m 0.99 99 2.0.99
1.00 1.00 100 2.1.0
1.0.0 1.0.0 100 2.1.0
1.0.0 (from here on, the 100 2.1.0
1.0.1 png.h string is 10001 2.1.0
1.0.1a-e identical to the 10002 from here on, the
1.0.2 source version) 10002 shared library is 2.V
1.0.2a-b 10003 where V is the source
1.0.1 10001 code version except as
1.0.1a-e 10002 2.1.0.1a-e noted.
1.0.2 10002 2.1.0.2
1.0.2a-b 10003 2.1.0.2a-b
1.0.3 10003 2.1.0.3
1.0.3a-d 10004 2.1.0.3a-d
1.0.4 10004 2.1.0.4
1.0.4a-f 10005 2.1.0.4a-f
1.0.5 (+ 2 patches) 10005 2.1.0.5
1.0.5a-d 10006 2.1.0.5a-d
1.0.5e-r 10100 2.1.0.5e-r
1.0.5s-v 10006 2.1.0.5s-v
1.0.6 (+ 3 patches) 10006 2.1.0.6
1.0.6d-g 10007 2.1.0.6d-g
1.0.6h 10007 10.6h
1.0.6i 10007 10.6i
1.0.6j 10007 2.1.0.6j
[devel] Imported from libpng-1.5.1beta11.tar
2011-01-28 17:58:40 +00:00
1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
1.0.7beta15-18 1 10007 2.1.0.7beta15-18
1.0.7rc1-2 1 10007 2.1.0.7rc1-2
1.0.7 1 10007 2.1.0.7
1.0.8beta1-4 1 10008 2.1.0.8beta1-4
1.0.8rc1 1 10008 2.1.0.8rc1
1.0.8 1 10008 2.1.0.8
1.0.9beta1-6 1 10009 2.1.0.9beta1-6
1.0.9rc1 1 10009 2.1.0.9rc1
1.0.9beta7-10 1 10009 2.1.0.9beta7-10
1.0.9rc2 1 10009 2.1.0.9rc2
1.0.9 1 10009 2.1.0.9
Imported from libpng-1.0.10rc1.tar
2001-03-23 11:06:56 +00:00
1.0.10beta1 1 10010 2.1.0.10beta1
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
1.0.10rc1 1 10010 2.1.0.10rc1
Imported from libpng-1.0.10.tar
2001-03-30 12:42:28 +00:00
1.0.10 1 10010 2.1.0.10
Imported from libpng-1.0.11beta3.tar
2001-04-15 01:15:41 +00:00
1.0.11beta1-3 1 10011 2.1.0.11beta1-3
Imported from libpng-1.0.11rc1.tar
2001-04-20 15:32:10 +00:00
1.0.11rc1 1 10011 2.1.0.11rc1
Imported from libpng-1.0.11.tar
2001-04-27 13:29:32 +00:00
1.0.11 1 10011 2.1.0.11
Imported from libpng-1.2.0beta4.tar
2001-06-23 13:03:17 +00:00
1.0.12beta1-2 2 10012 2.1.0.12beta1-2
1.0.12rc1 2 10012 2.1.0.12rc1
1.0.12 2 10012 2.1.0.12
1.1.0a-f - 10100 2.1.1.0a-f abandoned
Imported from libpng-1.2.0beta3.tar
2001-05-18 09:54:50 +00:00
1.2.0beta1-2 2 10200 2.1.2.0beta1-2
Imported from libpng-1.2.1beta1.tar
2001-10-19 01:55:13 +00:00
1.2.0beta3-5 3 10200 3.1.2.0beta3-5
1.2.0rc1 3 10200 3.1.2.0rc1
1.2.0 3 10200 3.1.2.0
Imported from libpng-1.2.1beta4.tar
2001-11-07 13:10:08 +00:00
1.2.1beta-4 3 10201 3.1.2.1beta1-4
Imported from libpng-1.2.1rc2.tar
2001-12-04 12:30:43 +00:00
1.2.1rc1-2 3 10201 3.1.2.1rc1-2
1.2.1 3 10201 3.1.2.1
Imported from libpng-1.2.2beta6.tar
2002-03-31 13:33:55 +00:00
1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6
Imported from libpng-1.2.2rc1.tar
2002-04-07 21:35:38 +00:00
1.0.13beta1 10 10013 10.so.0.1.0.13beta1
1.0.13rc1 10 10013 10.so.0.1.0.13rc1
1.2.2rc1 12 10202 12.so.0.1.2.2rc1
Imported from libpng-1.2.2.tar
2002-04-15 14:25:51 +00:00
1.0.13 10 10013 10.so.0.1.0.13
1.2.2 12 10202 12.so.0.1.2.2
Imported from libpng-1.2.3rc6.tar
2002-05-13 23:17:09 +00:00
1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6
1.2.3 12 10203 12.so.0.1.2.3
Imported from libpng-1.2.4beta3.tar
2002-06-28 14:34:00 +00:00
1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3
Imported from libpng-1.2.4rc1.tar
2002-07-02 03:23:46 +00:00
1.2.4rc1 13 10204 12.so.0.1.2.4rc1
Imported from libpng-1.2.4.tar
2002-07-08 00:15:20 +00:00
1.0.14 10 10014 10.so.0.1.0.14
1.2.4 13 10204 12.so.0.1.2.4
Imported from libpng-1.2.6beta3.tar
2004-07-18 03:45:44 +00:00
1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2
1.0.15rc1 10 10015 10.so.0.1.0.15rc1
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
1.0.15 10 10015 10.so.0.1.0.15
1.2.5 13 10205 12.so.0.1.2.5
1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4
Imported from libpng-1.2.6.tar
2004-08-15 12:15:39 +00:00
1.2.6rc1-5 13 10206 12.so.0.1.2.6rc1-5
1.0.16 10 10016 10.so.0.1.0.16
1.2.6 13 10206 12.so.0.1.2.6
Imported from libpng-1.2.7beta2.tar
2004-08-29 04:30:07 +00:00
1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2
Imported from libpng-1.2.7rc1.tar
2004-09-04 18:25:08 +00:00
1.0.17rc1 10 10017 12.so.0.1.0.17rc1
1.2.7rc1 13 10207 12.so.0.1.2.7rc1
Imported from libpng-1.2.7.tar
2004-09-12 02:19:54 +00:00
1.0.17 10 10017 12.so.0.1.0.17
1.2.7 13 10207 12.so.0.1.2.7
Imported from libpng-1.2.8beta5.tar
2004-11-20 17:18:40 +00:00
1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5
Imported from libpng-1.2.8rc5.tar
2004-11-29 21:08:00 +00:00
1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5
1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
Imported from libpng-1.2.8.tar
2004-12-03 00:14:51 +00:00
1.0.18 10 10018 12.so.0.1.0.18
1.2.8 13 10208 12.so.0.1.2.8
Imported from libpng-1.2.9beta5.tar
2006-03-04 22:50:47 +00:00
1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3
Imported from libpng-1.2.9beta11.tar
2006-03-22 22:21:59 +00:00
1.2.9beta4-11 13 10209 12.so.0.9[.0]
Imported from libpng-1.2.9rc1.tar
2006-03-31 11:29:33 +00:00
1.2.9rc1 13 10209 12.so.0.9[.0]
Imported from libpng-1.2.9.tar
2006-04-14 11:22:52 +00:00
1.2.9 13 10209 12.so.0.9[.0]
Imported from libpng-1.4.0beta2.tar
2006-04-21 02:31:14 +00:00
1.2.10beta1-7 13 10210 12.so.0.10[.0]
Imported from libpng-1.4.0beta1.tar
2006-04-20 12:20:46 +00:00
1.2.10rc1-2 13 10210 12.so.0.10[.0]
Imported from libpng-1.4.0beta3.tar
2006-05-10 12:27:44 +00:00
1.2.10 13 10210 12.so.0.10[.0]
Imported from libpng-1.4.0beta7.tar
2006-06-16 12:52:03 +00:00
1.4.0beta1-6 14 10400 14.so.0.0[.0]
[devel] Imported from libpng-1.4.0beta63.tar
2009-06-16 02:56:14 +00:00
1.2.11beta1-4 13 10210 12.so.0.11[.0]
Imported from libpng-1.4.0beta10.tar
2006-07-12 18:33:47 +00:00
1.4.0beta7-8 14 10400 14.so.0.0[.0]
Imported from libpng-1.4.0beta16.tar
2006-11-17 15:36:54 +00:00
1.2.11 13 10211 12.so.0.11[.0]
1.2.12 13 10212 12.so.0.12[.0]
1.4.0beta9-14 14 10400 14.so.0.0[.0]
1.2.13 13 10213 12.so.0.13[.0]
Imported from libpng-1.4.0beta36.tar
2008-10-26 01:03:28 +00:00
1.4.0beta15-36 14 10400 14.so.0.0[.0]
[devel] Bump version to 1.4.0beta87
2009-10-10 11:15:21 +00:00
1.4.0beta37-87 14 10400 14.so.14.0[.0]
[devel] Bump version to 1.4.0beta88
2009-10-30 05:00:15 +00:00
1.4.0rc01 14 10400 14.so.14.0[.0]
[devel] Imported from libpng-1.4.0rc02.tar
2009-12-20 21:14:57 +00:00
1.4.0beta88-109 14 10400 14.so.14.0[.0]
[devel] Imported from libpng-1.4.0rc08.tar
2010-01-02 00:26:18 +00:00
1.4.0rc02-08 14 10400 14.so.14.0[.0]
[devel] Imported from libpng-1.4.0rc04.tar
2009-12-25 20:24:18 +00:00
1.4.0 14 10400 14.so.14.0[.0]
[devel] Imported from libpng-1.5.0beta01.tar
2010-02-08 00:08:50 +00:00
1.4.1beta01-03 14 10401 14.so.14.1[.0]
1.4.1rc01 14 10401 14.so.14.1[.0]
[devel] Imported from libpng-1.5.0beta06.tar
2010-02-14 13:16:19 +00:00
1.4.1beta04-12 14 10401 14.so.14.1[.0]
[devel] Bump to version libpng-1.5.0beta12
2010-03-08 17:20:30 +00:00
1.4.1 14 10401 14.so.14.1[.0]
[devel] Imported from libpng-1.5.0beta26.tar
2010-06-19 02:55:53 +00:00
1.4.2 14 10402 14.so.14.2[.0]
1.4.3 14 10403 14.so.14.3[.0]
[devel] Bump to version libpng-1.5.0beta56
2010-11-21 21:18:02 +00:00
1.4.4 14 10404 14.so.14.4[.0]
[devel] Imported from libpng-1.5.0rc01.tar
2010-12-27 14:53:08 +00:00
1.5.0beta01-58 15 10500 15.so.15.0[.0]
[devel] Update copyright year and bump to version libpng-1.5.0rc07
2011-01-04 15:57:06 +00:00
1.5.0rc01-07 15 10500 15.so.15.0[.0]
[devel] Imported from libpng-1.5.0.tar
2011-01-06 12:42:51 +00:00
1.5.0 15 10500 15.so.15.0[.0]
[devel] Imported from libpng-1.5.1beta11.tar
2011-01-28 21:20:34 +00:00
1.5.1beta01-11 15 10501 15.so.15.1[.0]
--amend [devel] Imported from libpng-1.5.1.tar
2011-02-03 04:58:27 +00:00
1.5.1rc01-02 15 10501 15.so.15.1[.0]
1.5.1 15 10501 15.so.15.1[.0]
[devel] Imported from libpng-1.5.2rc01.tar
2011-03-19 03:02:20 +00:00
1.5.2beta01-03 15 10502 15.so.15.2[.0]
[devel] Bump to version libpng-1.5.2rc03
2011-03-24 13:59:48 +00:00
1.5.2rc01-03 15 10502 15.so.15.2[.0]
[devel] Imported from libpng-1.5.2.tar
2011-03-31 16:23:49 +00:00
1.5.2 15 10502 15.so.15.2[.0]
[devel] Imported from libpng-1.5.3rc01.tar
2011-06-03 12:15:04 +00:00
1.5.3beta01-10 15 10503 15.so.15.3[.0]
[devel] Bump version to libpng-1.5.3beta11
2011-06-11 01:43:39 +00:00
1.5.3rc01-02 15 10503 15.so.15.3[.0]
[devel] Added png_set_chop_16() API.
2011-06-14 03:07:37 +00:00
1.5.3beta11 15 10503 15.so.15.3[.0]
1.5.3 [omitted]
[devel] Imported from libpng-1.5.4beta08.tar
2011-06-23 04:10:36 +00:00
1.5.4beta01-08 15 10504 15.so.15.4[.0]
[devel] Imported from libpng-1.5.4rc01.tar
2011-06-30 23:59:45 +00:00
1.5.4rc01 15 10504 15.so.15.4[.0]
[devel] Imported from libpng-1.5.4.tar
2011-07-07 11:24:57 +00:00
1.5.4 15 10504 15.so.15.4[.0]
[libpng15] Bump version to libpng-1.5.5beta08
2011-09-09 11:02:09 +00:00
1.5.5beta01-08 15 10505 15.so.15.5[.0]
1.5.5rc01 15 10505 15.so.15.5[.0]
[libpng15] Imported from libpng-1.5.5.tar
2011-09-22 13:40:32 +00:00
1.5.5 15 10505 15.so.15.5[.0]
[libpng15] Imported from libpng-1.5.6rc01.tar
2011-10-26 13:36:21 +00:00
1.5.6beta01-07 15 10506 15.so.15.6[.0]
[libpng15] Imported from libpng-1.5.6.tar
2011-11-03 03:43:00 +00:00
1.5.6rc01-03 15 10506 15.so.15.6[.0]
1.5.6 15 10506 15.so.15.6[.0]
[libpng15] Bump version to libpng-1.5.7beta05
2011-11-18 03:14:34 +00:00
1.5.7beta01-05 15 10507 15.so.15.7[.0]
[libpng15] Bump version to libpng-1.6.0beta03
2011-12-21 14:37:46 +00:00
1.5.7rc01-03 15 10507 15.so.15.7[.0]
1.5.7 15 10507 15.so.15.7[.0]
[libpng16] Bump version to 1.6.1beta05
2013-03-02 20:58:22 +00:00
1.6.0beta01-40 16 10600 16.so.16.0[.0]
1.6.0rc01-08 16 10600 16.so.16.0[.0]
1.6.0 16 10600 16.so.16.0[.0]
[libpng16] Bump version to 1.6.2beta01
2013-03-29 11:56:45 +00:00
1.6.1beta01-09 16 10601 16.so.16.1[.0]
[libpng16] Imported from libpng-1.6.1rc01.tar
2013-03-21 12:27:01 +00:00
1.6.1rc01 16 10601 16.so.16.1[.0]
[libpng16] Imported from libpng-1.6.1.tar
2013-03-28 01:31:36 +00:00
1.6.1 16 10601 16.so.16.1[.0]
[libpng16] Imported from libpng-1.6.2rc01.tar
2013-04-18 11:23:26 +00:00
1.6.2beta01 16 10602 16.so.16.2[.0]
[libpng16] Imported from libpng-1.6.2rc06.tar
2013-04-24 03:17:03 +00:00
1.6.2rc01-06 16 10602 16.so.16.2[.0]
[libpng16] Imported from libpng-1.6.2.tar
2013-04-25 12:24:46 +00:00
1.6.2 16 10602 16.so.16.2[.0]
[libpng16] Bump version to 1.6.3beta09
2013-06-18 18:23:54 +00:00
1.6.3beta01-09 16 10603 16.so.16.3[.0]
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
Henceforth the source version will match the shared-library minor
and patch numbers; the shared-library major version number will be
used for changes in backward compatibility, as it is intended. The
PNG_PNGLIB_VER macro, which is not used within libpng but is available
for applications, is an unsigned integer of the form xyyzz corresponding
to the source version x.y.z (leading zeros in y and z). Beta versions
Imported from libpng-1.0.10rc1.tar
2001-03-23 11:06:56 +00:00
were given the previous public release number plus a letter, until
version 1.0.6j; from then on they were given the upcoming public
release number plus "betaNN" or "rcN".
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.SH "SEE ALSO"
[devel] Revised the "SEE ALSO" lines in manpages to look like those in "man man"
2010-03-03 16:45:50 +00:00
.BR "png"(5), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
[devel] Fixed formatting of the "See also" line in man pages.
2010-03-03 15:47:49 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
.LP
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.IR libpng :
.IP
Imported from libpng-1.2.7beta1.tar
2004-08-26 03:00:45 +00:00
http://libpng.sourceforge.net (follow the [DOWNLOAD] link)
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
http://www.libpng.org/pub/png
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
.LP
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.IR zlib :
.IP
(generally) at the same location as
.I libpng
or at
.br
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
ftp://ftp.info-zip.org/pub/infozip/zlib
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
.LP
.IR PNG specification: RFC 2083
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.IP
(generally) at the same location as
.I libpng
or at
.br
ftp://ds.internic.net/rfc/rfc2083.txt
.br
or (as a W3C Recommendation) at
.br
http://www.w3.org/TR/REC-png.html
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99e.tar
1998-02-28 13:00:24 +00:00
.LP
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
In the case of any inconsistency between the PNG specification
and this library, the specification takes precedence.
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.SH AUTHORS
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
This man page: Glenn Randers-Pehrson
Imported from libpng-1.2.8rc1.tar
2004-11-24 13:50:16 +00:00
<glennrp at users.sourceforge.net>
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
The contributing authors would like to thank all those who helped
with testing, bug fixes, and patience. This wouldn't have been
possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation.
Imported from libpng-1.0.5h.tar
1999-12-10 15:43:02 +00:00
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
Libpng version 1.6.3beta09 - June 27, 2013:
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Imported from libpng-1.2.8rc1.tar
2004-11-24 13:50:16 +00:00
Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Supported by the PNG development group
.br
Imported from libpng-1.2.9beta1.tar
2006-02-21 04:09:05 +00:00
png-mng-implement at lists.sf.net
(subscription required; visit
Imported from libpng-1.2.9beta3.tar
2006-02-24 12:30:16 +00:00
png-mng-implement at lists.sourceforge.net (subscription required; visit
Imported from libpng-1.2.9beta1.tar
2006-02-21 04:09:05 +00:00
https://lists.sourceforge.net/lists/listinfo/png-mng-implement
to subscribe).
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
.SH COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Imported from libpng-1.0.9beta1.tar
2000-11-10 18:26:19 +00:00
(This copy of the libpng notices is provided for your convenience. In case of
any discrepancy between this copy and the notices in the file png.h that is
included in the libpng distribution, the latter shall prevail.)
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
If you modify libpng you may insert additional notices immediately following
this sentence.
Imported from libpng-1.0.4c.tar
1999-10-01 19:22:25 +00:00
[devel] Imported from libpng-1.4.0beta66.tar
2009-06-27 02:46:52 +00:00
This code is released under the libpng license.
[devel] Revise references to zlib-libpng license
2009-06-24 15:27:36 +00:00
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
libpng versions 1.2.6, August 15, 2004, through 1.6.3beta09, June 27, 2013, are
Imported from libpng-1.4.0beta19.tar
2007-05-15 21:16:34 +00:00
Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
distributed according to the same disclaimer and license as libpng-1.2.5
Imported from libpng-1.2.6rc3.tar
2004-08-10 02:50:32 +00:00
with the following individual added to the list of Contributing Authors
Imported from libpng-1.2.6beta4.tar
2004-07-28 13:20:44 +00:00
Cosmin Truta
libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
Imported from libpng-1.2.2beta2.tar
2002-02-24 00:55:25 +00:00
Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
Imported from libpng-1.0.8.tar
2000-07-24 11:34:14 +00:00
distributed according to the same disclaimer and license as libpng-1.0.6
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
with the following individuals added to the list of Contributing Authors
Simon-Pierre Cadieux
Eric S. Raymond
Gilles Vollant
and with the following additions to the disclaimer:
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
There is no warranty against interference with your
enjoyment of the library or against infringement.
There is no warranty that our efforts or the library
will fulfill any of your particular purposes or needs.
This library is provided with all faults, and the entire
risk of satisfactory quality, performance, accuracy, and
effort is with the user.
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
Copyright (c) 1998, 1999 Glenn Randers-Pehrson
Distributed according to the same disclaimer and license as libpng-0.96,
with the following individuals added to the list of Contributing Authors:
Tom Lane
Glenn Randers-Pehrson
Willem van Schaik
libpng versions 0.89, June 1996, through 0.96, May 1997, are
Copyright (c) 1996, 1997 Andreas Dilger
Distributed according to the same disclaimer and license as libpng-0.88,
with the following individuals added to the list of Contributing Authors:
Imported from libpng-1.0.4c.tar
1999-10-01 19:22:25 +00:00
John Bowler
Kevin Bracey
Sam Bushell
Magnus Holmgren
Greg Roelofs
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
Tom Tanner
libpng versions 0.5, May 1995, through 0.88, January 1996, are
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
For the purposes of this copyright and license, "Contributing Authors"
is defined as the following set of individuals:
Andreas Dilger
Dave Martindale
Imported from libpng-1.0.4c.tar
1999-10-01 19:22:25 +00:00
Guy Eric Schalnat
Paul Schmidt
Tim Wegner
Imported from libpng-1.0.2b.tar
1999-01-07 03:50:16 +00:00
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
The PNG Reference Library is supplied "AS IS". The Contributing Authors
and Group 42, Inc. disclaim all warranties, expressed or implied,
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
including, without limitation, the warranties of merchantability and of
fitness for any purpose. The Contributing Authors and Group 42, Inc.
assume no liability for direct, indirect, incidental, special, exemplary,
or consequential damages, which may result from the use of the PNG
Reference Library, even if advised of the possibility of such damage.
Imported from libpng-0.99d.tar
1998-02-09 02:56:40 +00:00
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Permission is hereby granted to use, copy, modify, and distribute this
source code, or portions hereof, for any purpose, without fee, subject
to the following restrictions:
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
1. The origin of this source code must not be misrepresented.
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
2. Altered versions must be plainly marked as such and
must not be misrepresented as being the original source.
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
Imported from libpng-1.0.10beta1.tar
2001-03-14 13:08:39 +00:00
3. This Copyright notice may not be removed or altered from
any source or altered source distribution.
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
The Contributing Authors and Group 42, Inc. specifically permit, without
fee, and encourage the use of this source code as a component to
supporting the PNG file format in commercial products. If you use this
source code in a product, acknowledgment is not required but would be
appreciated.
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
A "png_get_copyright" function is available, for convenient use in "about"
boxes and the like:
printf("%s",png_get_copyright(NULL));
Also, the PNG logo (in PNG format, of course) is supplied in the
Imported from libpng-1.0.8beta4.tar
2000-07-14 13:15:12 +00:00
files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
Imported from libpng-1.0.4-pre1.tar
1999-09-17 17:27:26 +00:00
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
Imported from libpng-1.0.4c.tar
1999-10-01 19:22:25 +00:00
certification mark of the Open Source Initiative.
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
Glenn Randers-Pehrson
Imported from libpng-1.2.8rc1.tar
2004-11-24 13:50:16 +00:00
glennrp at users.sourceforge.net
[libpng16] Imported from libpng-1.6.3beta09.tar
2013-06-27 21:56:16 +00:00
June 27, 2013
Imported from libpng-1.0.7.tar
2000-07-01 20:37:28 +00:00
Imported from libpng-0.99c.tar
1998-02-07 16:20:57 +00:00
.\" end of man page
Reference in New Issue Copy Permalink