gtk/gdk-pixbuf/io-png.c
Jonathan Blandford 14237d13e2 make the symlink. Does not work for srcdir != buildir != . Beats me why; I
1999-11-22  Jonathan Blandford  <jrb@redhat.com>

	* configure.in (GDK_PIXBUF_DIR): make the symlink.  Does not work
	for srcdir != buildir != .  Beats me why; I can't figure it out.
	AC_OUTPUT_COMMANDS doesn't seem to let me substitute it correctly.
1999-11-22 20:43:58 +00:00

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/* GdkPixbuf library - JPEG image loader
*
* Copyright (C) 1999 Mark Crichton
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Mark Crichton <crichton@gimp.org>
* Federico Mena-Quintero <federico@gimp.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include <stdio.h>
#include <png.h>
#include "gdk-pixbuf/gdk-pixbuf.h"
#include "gdk-pixbuf/gdk-pixbuf-io.h"
static void
setup_png_transformations(png_structp png_read_ptr, png_infop png_info_ptr,
gboolean *fatal_error_occurred,
png_uint_32* width_p, png_uint_32* height_p,
int* color_type_p)
{
png_uint_32 width, height;
int bit_depth, color_type, interlace_type, compression_type, filter_type;
int channels;
/* Get the image info */
png_get_IHDR (png_read_ptr, png_info_ptr,
&width, &height,
&bit_depth,
&color_type,
&interlace_type,
&compression_type,
&filter_type);
/* set_expand() basically needs to be called unless
we are already in RGB/RGBA mode
*/
if (color_type == PNG_COLOR_TYPE_PALETTE &&
bit_depth <= 8) {
/* Convert indexed images to RGB */
png_set_expand (png_read_ptr);
} else if (color_type == PNG_COLOR_TYPE_GRAY &&
bit_depth < 8) {
/* Convert grayscale to RGB */
png_set_expand (png_read_ptr);
} else if (png_get_valid (png_read_ptr,
png_info_ptr, PNG_INFO_tRNS)) {
/* If we have transparency header, convert it to alpha
channel */
png_set_expand(png_read_ptr);
} else if (bit_depth < 8) {
/* If we have < 8 scale it up to 8 */
png_set_expand(png_read_ptr);
/* Conceivably, png_set_packing() is a better idea;
* God only knows how libpng works
*/
}
/* If we are 16-bit, convert to 8-bit */
if (bit_depth == 16) {
png_set_strip_16(png_read_ptr);
}
/* If gray scale, convert to RGB */
if (color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
png_set_gray_to_rgb(png_read_ptr);
}
/* If interlaced, handle that */
if (interlace_type != PNG_INTERLACE_NONE) {
png_set_interlace_handling(png_read_ptr);
}
/* Update the info the reflect our transformations */
png_read_update_info(png_read_ptr, png_info_ptr);
png_get_IHDR (png_read_ptr, png_info_ptr,
&width, &height,
&bit_depth,
&color_type,
&interlace_type,
&compression_type,
&filter_type);
*width_p = width;
*height_p = height;
*color_type_p = color_type;
#ifndef G_DISABLE_CHECKS
/* Check that the new info is what we want */
if (bit_depth != 8) {
g_warning("Bits per channel of transformed PNG is %d, not 8.", bit_depth);
*fatal_error_occurred = TRUE;
return;
}
if ( ! (color_type == PNG_COLOR_TYPE_RGB ||
color_type == PNG_COLOR_TYPE_RGB_ALPHA) ) {
g_warning("Transformed PNG not RGB or RGBA.");
*fatal_error_occurred = TRUE;
return;
}
channels = png_get_channels(png_read_ptr, png_info_ptr);
if ( ! (channels == 3 || channels == 4) ) {
g_warning("Transformed PNG has %d channels, must be 3 or 4.", channels);
*fatal_error_occurred = TRUE;
return;
}
#endif
}
/* Destroy notification function for the libart pixbuf */
static void
free_buffer (gpointer user_data, gpointer data)
{
free (data);
}
/* Shared library entry point */
GdkPixbuf *
image_load (FILE *f)
{
png_structp png_ptr;
png_infop info_ptr, end_info;
gboolean failed = FALSE;
gint i, ctype, bpp;
png_uint_32 w, h;
png_bytepp rows;
guchar *pixels;
png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
return NULL;
info_ptr = png_create_info_struct (png_ptr);
if (!info_ptr) {
png_destroy_read_struct (&png_ptr, NULL, NULL);
return NULL;
}
end_info = png_create_info_struct (png_ptr);
if (!end_info) {
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
return NULL;
}
if (setjmp (png_ptr->jmpbuf)) {
png_destroy_read_struct (&png_ptr, &info_ptr, &end_info);
return NULL;
}
png_init_io (png_ptr, f);
png_read_info (png_ptr, info_ptr);
setup_png_transformations(png_ptr, info_ptr, &failed, &w, &h, &ctype);
if (failed) {
png_destroy_read_struct (&png_ptr, &info_ptr, &end_info);
return NULL;
}
if (ctype & PNG_COLOR_MASK_ALPHA)
bpp = 4;
else
bpp = 3;
pixels = malloc (w * h * bpp);
if (!pixels) {
png_destroy_read_struct (&png_ptr, &info_ptr, &end_info);
return NULL;
}
rows = g_new (png_bytep, h);
for (i = 0; i < h; i++)
rows[i] = pixels + i * w * bpp;
png_read_image (png_ptr, rows);
png_destroy_read_struct (&png_ptr, &info_ptr, &end_info);
g_free (rows);
if (ctype & PNG_COLOR_MASK_ALPHA)
return gdk_pixbuf_new_from_data (pixels, ART_PIX_RGB, TRUE,
w, h, w * 4,
free_buffer, NULL);
else
return gdk_pixbuf_new_from_data (pixels, ART_PIX_RGB, FALSE,
w, h, w * 3,
free_buffer, NULL);
}
/* These avoid the setjmp()/longjmp() crap in libpng */
static void png_error_callback (png_structp png_read_ptr,
png_const_charp error_msg);
static void png_warning_callback(png_structp png_read_ptr,
png_const_charp warning_msg);
/* Called at the start of the progressive load */
static void png_info_callback (png_structp png_read_ptr,
png_infop png_info_ptr);
/* Called for each row; note that you will get duplicate row numbers
for interlaced PNGs */
static void png_row_callback (png_structp png_read_ptr,
png_bytep new_row,
png_uint_32 row_num,
int pass_num);
/* Called after reading the entire image */
static void png_end_callback (png_structp png_read_ptr,
png_infop png_info_ptr);
typedef struct _LoadContext LoadContext;
struct _LoadContext {
png_structp png_read_ptr;
png_infop png_info_ptr;
ModulePreparedNotifyFunc notify_func;
gpointer notify_user_data;
GdkPixbuf* pixbuf;
guint fatal_error_occurred : 1;
};
gpointer
image_begin_load (ModulePreparedNotifyFunc prepare_func,
ModuleUpdatedNotifyFunc update_func,
gpointer user_data)
{
LoadContext* lc;
lc = g_new0(LoadContext, 1);
lc->fatal_error_occurred = FALSE;
lc->notify_func = prepare_func;
lc->notify_user_data = user_data;
/* Create the main PNG context struct */
lc->png_read_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
lc, /* error/warning callback data */
png_error_callback,
png_warning_callback);
if (lc->png_read_ptr == NULL) {
g_free(lc);
return NULL;
}
/* Create the auxiliary context struct */
lc->png_info_ptr = png_create_info_struct(lc->png_read_ptr);
if (lc->png_info_ptr == NULL) {
png_destroy_read_struct(&lc->png_read_ptr, NULL, NULL);
g_free(lc);
return NULL;
}
png_set_progressive_read_fn(lc->png_read_ptr,
lc, /* callback data */
png_info_callback,
png_row_callback,
png_end_callback);
return lc;
}
void
image_stop_load (gpointer context)
{
LoadContext* lc = context;
g_return_if_fail(lc != NULL);
gdk_pixbuf_unref(lc->pixbuf);
png_destroy_read_struct(&lc->png_read_ptr, NULL, NULL);
g_free(lc);
}
gboolean
image_load_increment(gpointer context, guchar *buf, guint size)
{
LoadContext* lc = context;
g_return_val_if_fail(lc != NULL, FALSE);
/* Invokes our callbacks as needed */
png_process_data(lc->png_read_ptr, lc->png_info_ptr, buf, size);
if (lc->fatal_error_occurred)
return FALSE;
else
return TRUE;
}
/* Called at the start of the progressive load, once we have image info */
static void
png_info_callback (png_structp png_read_ptr,
png_infop png_info_ptr)
{
LoadContext* lc;
png_uint_32 width, height;
int color_type;
gboolean have_alpha = FALSE;
gboolean failed = FALSE;
lc = png_get_progressive_ptr(png_read_ptr);
if (lc->fatal_error_occurred)
return;
setup_png_transformations(lc->png_read_ptr,
lc->png_info_ptr,
&failed,
&width, &height, &color_type);
if (failed) {
lc->fatal_error_occurred = TRUE;
return;
}
/* If we have alpha, set a flag */
if (color_type & PNG_COLOR_MASK_ALPHA)
have_alpha = TRUE;
lc->pixbuf = gdk_pixbuf_new(ART_PIX_RGB, have_alpha, 8, width, height);
if (lc->pixbuf == NULL) {
/* Failed to allocate memory */
lc->fatal_error_occurred = TRUE;
return;
}
/* Notify the client that we are ready to go */
if (lc->notify_func)
(* lc->notify_func) (lc->pixbuf, lc->notify_user_data);
return;
}
/* Called for each row; note that you will get duplicate row numbers
for interlaced PNGs */
static void
png_row_callback (png_structp png_read_ptr,
png_bytep new_row,
png_uint_32 row_num,
int pass_num)
{
LoadContext* lc;
guchar* old_row = NULL;
lc = png_get_progressive_ptr(png_read_ptr);
if (lc->fatal_error_occurred)
return;
old_row = lc->pixbuf->art_pixbuf->pixels + (row_num * lc->pixbuf->art_pixbuf->rowstride);
png_progressive_combine_row(lc->png_read_ptr, old_row, new_row);
}
/* Called after reading the entire image */
static void
png_end_callback (png_structp png_read_ptr,
png_infop png_info_ptr)
{
LoadContext* lc;
lc = png_get_progressive_ptr(png_read_ptr);
if (lc->fatal_error_occurred)
return;
/* Doesn't do anything for now */
}
static void
png_error_callback(png_structp png_read_ptr,
png_const_charp error_msg)
{
LoadContext* lc;
lc = png_get_error_ptr(png_read_ptr);
lc->fatal_error_occurred = TRUE;
fprintf(stderr, "Fatal error loading PNG: %s\n", error_msg);
}
static void
png_warning_callback(png_structp png_read_ptr,
png_const_charp warning_msg)
{
LoadContext* lc;
lc = png_get_error_ptr(png_read_ptr);
fprintf(stderr, "Warning loading PNG: %s\n", warning_msg);
}