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[devel] Revised libpng.txt about 1.2.x->1.4.0 differences

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Glenn Randers-Pehrson 2009-10-29 23:34:44 -05:00
parent dfa99afe40
commit 4f25bf37c2
1 changed files with 47 additions and 43 deletions
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90
libpng-1.4.0beta87.txt
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@ -2959,17 +2959,6 @@ selection of assembler code features:
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.
IX. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
Private libpng prototypes and macro definitions were moved from
png.h and pngconf.h into a new pngpriv.h header file.
Support for the iTXt chunk has been enabled by default.
Support for global arrays was removed.
Some obsolete/deprecated macros and functions have been removed.
These macros are deprecated:
PNG_READ_TRANSFORMS_NOT_SUPPORTED
@ -2988,12 +2977,6 @@ They have been replaced, respectively, by:
PNG_NO_READ_ANCILLARY_CHUNKS
PNG_NO_WRITE_ANCILLARY_CHUNKS
The PNG_1_0_X and PNG_1_2_X macros were eliminated.
The PNG_LEGACY_SUPPORTED macro was eliminated.
Many WIN32_WCE #ifdefs were removed.
PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been
deprecated since libpng-1.0.16 and libpng-1.2.6.
@ -3003,20 +2986,12 @@ was replaced with
!png_sig_cmp(sig, 0, num)
It has been deprecated since libpng-0.90.
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.
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.
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.
Functions png_set_benign_errors(), png_benign_error(), and
png_chunk_benign_error() were added.
@ -3028,6 +3003,51 @@ were added to the library.
We implemented support for I/O states. Added png_ptr member io_state, and
functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
The png_calloc() function was added and is used in place of
of "png_malloc(); png_memset();" except in the case in png_read_png()
where the array consists of pointers; in this case a "for" loop is used
after the png_malloc() to set the pointers to NULL.
We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
input transforms.
We added the png_set_premultiply_alpha and
png_do_read_premultiply_alpha() functions.
The call to png_do_chop() in pngrtran.c, which reduces 16-bit input
files to 8-bit bit depth, was relocated ahead of the building
of gamma tables. This allows us to build 8-bit tables instead
of 16-bit tables, when only 8-bit tables are needed. This avoids
wasting some computing resources when the application has called
the png_set_strip_16() function and encounters a 16-bit PNG file.
Checking for and reporting of errors in the IHDR chunk is more thorough.
IX. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
Private libpng prototypes and macro definitions were moved from
png.h and pngconf.h into a new pngpriv.h header file.
Support for the iTXt chunk has been enabled by default.
Support for global arrays was removed.
Some obsolete/deprecated macros and functions have been removed.
The PNG_1_0_X and PNG_1_2_X macros were eliminated.
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.
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.
The png_permit_empty_plte() was removed. It has been deprecated
since libpng-1.0.9. Use png_permit_mng_features() instead.
@ -3052,28 +3072,11 @@ allocates.
The png_zalloc() and png_zfree() functions are no longer exported.
The png_calloc() function was added and is used in place of
of "png_malloc(); png_memset();" except in the case in png_read_png()
where the array consists of pointers; in this case a "for" loop is used
after the png_malloc() to set the pointers to NULL.
We removed the trailing '.' from the warning and error messages.
We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
input transforms.
The png_struct and info_struct members "trans" and "trans_values" were
changed to "trans_alpha" and "trans_color", respectively.
The call to png_do_chop() in pngrtran.c, which reduces 16-bit input
files to 8-bit bit depth, was relocated ahead of the building
of gamma tables. This allows us to build 8-bit tables instead
of 16-bit tables, when only 8-bit tables are needed. This avoids
wasting some computing resources when the application has called
the png_set_strip_16() function and encounters a 16-bit PNG file.
Checking for and reporting of errors in the IHDR chunk is more thorough.
X. Detecting libpng
The png_get_io_ptr() function has been present since libpng-0.88, has never
@ -3181,7 +3184,8 @@ We mark all non-exported functions with "/* PRIVATE */"":
}
The prototypes for non-exported functions (except for those in
pngtest) appear in pngpriv.h
pngtest) appear in
pngpriv.h
above the comment that says
/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */