forked from AuroraMiddleware/gtk
Redid io-png for gdk-pixbuf. Note that it'll add an opaque alpha channel
Redid io-png for gdk-pixbuf. Note that it'll add an opaque alpha channel to any png that doesn't have one, and will convert greyscale PNGs to RGBA.
This commit is contained in:
Mark Crichton
parent
fee33a543d
commit
8854db3c4f
@ -1,90 +1,146 @@
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/*
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* io-png.c: GdkPixBuf image loader for PNG files.
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* io-png.c: GdkPixBuf I/O 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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* Mark Crichton <crichton@gimp.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 <glib.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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GdkPixBuf *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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png_structp png_ptr;
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png_infop info_ptr, end_info;
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gint i, depth, ctype, inttype, passes;
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png_uint_32 w, h, x, y;
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png_bytepp rows;
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art_u8 *pixels, *temp, *rowdata;
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GdkPixBuf *pixbuf;
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g_return_val_if_fail (f != NULL, NULL);
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png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL,
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NULL);
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info_ptr = png_create_info_struct (png_ptr);
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if (!info_ptr) {
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png_destroy_read_struct(&png_ptr, NULL, NULL);
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return NULL;
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}
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end_info = png_create_info_struct (png_ptr);
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if (!end_info) {
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png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
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return NULL;
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}
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if (setjmp(png_ptr->jmpbuf)) {
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return NULL;
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}
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png_init_io(png_ptr, f);
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png_read_info(png_ptr, info_ptr);
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png_get_IHDR(png_ptr, info_ptr, &w, &h, &depth, &ctype, &inttype,
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NULL, NULL);
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/* Ok, we want to work with 24 bit images.
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* However, PNG can vary depth per channel.
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* So, we use the png_set_expand function to expand
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* everything into a format libart expects.
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* We also use png_set_strip_16 to reduce down to 8 bit/chan.
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*/
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if (ctype == PNG_COLOR_TYPE_PALETTE && depth <= 8)
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png_set_expand(png_ptr);
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if (ctype == PNG_COLOR_TYPE_GRAY && depth < 8)
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png_set_expand(png_ptr);
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if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
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png_set_expand(png_ptr);
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if (depth == 16)
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png_set_strip_16(png_ptr);
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/* We also have png "packing" bits into bytes if < 8 */
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if (depth < 8)
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png_set_packing(png_ptr);
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/* Add filler bits to non-alpha PNGs */
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/* make it 255, full opaque */
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if (depth == 8 && ctype == PNG_COLOR_TYPE_RGB)
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png_set_filler(png_ptr, 0xFF, PNG_FILLER_AFTER);
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/* Lastly, if the PNG is greyscale, convert to RGB */
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if (ctype == PNG_COLOR_TYPE_GRAY || ctype == PNG_COLOR_TYPE_GRAY_ALPHA)
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png_set_gray_to_rgb(png_ptr);
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/* ...and if we're interlaced... */
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passes = png_set_interlace_handling(png_ptr);
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/* Update our info structs */
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png_read_update_info(png_ptr, info_ptr);
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/* Allocate some memory and set up row array */
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/* This "inhales vigirously"... */
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pixels = g_malloc(w*h*4);
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rows = g_malloc(h*sizeof(png_bytep));
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if ((!pixels) || (!rows)) {
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return NULL;
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}
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/* Icky code, but it has to be done... */
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for (i = 0; i < h; i++) {
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if ((rows[i] = g_malloc(w*sizeof(art_u8)*4)) == NULL) {
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int n;
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for (n = 0; n < i; n++)
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g_free(rows[i]);
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g_free(rows);
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return NULL;
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}
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}
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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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/* And we FINALLY get here... */
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png_read_image(png_ptr, rows);
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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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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/* Now stuff the bytes into pixels & free rows[y] */
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/* RGBA order */
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temp = pixels;
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for (y = 0; y < h; y++) {
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(png_bytep)rowdata = rows[y];
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for (x = 0; x < w; x++) {
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temp[0] = rowdata[(x*4)];
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temp[1] = rowdata[(x*4)+1];
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temp[2] = rowdata[(x*4)+2];
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temp[3] = rowdata[(x*4)+3];
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temp += 4;
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}
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g_free(rows[y]);
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}
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g_free(rows);
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number_passes = png_set_interlace_handling (png);
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/* Return the GdkPixBuf */
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pixbuf = g_new(GdkPixBuf, 1);
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pixbuf->art_pixbuf = art_pixbuf_new_rgba (pixels, w, h, (w*4));
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/* Ok, I'm anal...shoot me */
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if (!(pixbuf->art_pixbuf))
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return NULL;
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pixbuf->ref_count = 0;
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pixbuf->unref_func = NULL;
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return pixbuf;
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}
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