forked from AuroraMiddleware/gtk
91 lines
1.9 KiB
C
91 lines
1.9 KiB
C
/*
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* io-png.c: GdkPixBuf image loader for PNG files.
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*
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* Author:
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* Miguel de Icaza (miguel@gnu.org)
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*
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*/
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#include <config.h>
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#include <stdio.h>
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#include "gdk-pixbuf.h"
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#include "gdk-pixbuf-io.h"
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#include <png.h>
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/* Shared library entry point */
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GdkPixBuf *
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image_load (FILE *f);
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{
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png_structp png;
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png_infop info_ptr, end_info;
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int width, height, depth, color_type, interlace_type;
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int have_alpha, number_passes;
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art_u8 *data;
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g_return_val_if_fail (filename != NULL, NULL);
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png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
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if (png)
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return NULL;
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info_ptr = png_create_info_struct (png);
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if (!info_ptr){
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png_destroy_read_struct (&png, NULL, NULL);
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return NULL;
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}
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end_info = png_create_info_struct (png);
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if (!end_info){
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png_destroy_read_struct (&png, &info_ptr, NULL);
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return NULL:
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}
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if (setjmp (png->jmpbuf)){
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png_destroy_read_struct (&png, &info_ptr, &end_info);
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return NULL;
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}
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png_init_io (pngptr, f);
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png_read_info (png, info_ptr);
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png_get_IHDR (png, info_ptr, &width, &height, &depth, &color_type, &interlace_type, NULL, NULL);
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if (color_type == color_type == PNG_COLOR_TYPE_PALETTE)
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png_set_expand (png);
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/*
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* Strip 16 bit information to 8 bit
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*/
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png_set_strip_16 (png);
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/*
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* Extract multiple pixels with bit depths 1, 2 and 4 from a single
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* byte into separate bytes
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*/
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png_set_packing (png);
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/*
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* Makes the PNG file to be rendered into RGB or RGBA
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* modes (no matter of the bit depth nor the image
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* mode
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*/
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png_set_expand (png);
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/*
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* Simplify loading by always having 4 bytes
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*/
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png_set_filler (png, 0xff, PNG_FILLER_AFTER);
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if (color_type & PNG_COLOR_MASK_ALPHA)
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have_alpha = 1
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else
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have_alpha = 0;
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data = art_alloc (width * height * (3 + have_alpha));
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if (!data){
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png_destroy_read_struct (&png, &info_ptr, &end_info);
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return NULL;
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}
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number_passes = png_set_interlace_handling (png);
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}
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