Commit 8854db3c authored by Mark Crichton's avatar Mark Crichton
Browse files

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.
parent fee33a54
/*
* io-png.c: GdkPixBuf image loader for PNG files.
* io-png.c: GdkPixBuf I/O for PNG files.
*
* Author:
* Miguel de Icaza (miguel@gnu.org)
* Mark Crichton <crichton@gimp.org>
*
*/
#include <config.h>
#include <stdio.h>
#include <glib.h>
#include "gdk-pixbuf.h"
#include "gdk-pixbuf-io.h"
#include <png.h>
/* Shared library entry point */
GdkPixBuf *
image_load (FILE *f);
GdkPixBuf *image_load(FILE * f)
{
png_structp png;
png_infop info_ptr, end_info;
int width, height, depth, color_type, interlace_type;
int have_alpha, number_passes;
art_u8 *data;
g_return_val_if_fail (filename != NULL, NULL);
png_structp png_ptr;
png_infop info_ptr, end_info;
gint i, depth, ctype, inttype, passes;
png_uint_32 w, h, x, y;
png_bytepp rows;
art_u8 *pixels, *temp, *rowdata;
GdkPixBuf *pixbuf;
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png)
return NULL;
g_return_val_if_fail (f != NULL, NULL);
info_ptr = png_create_info_struct (png);
if (!info_ptr){
png_destroy_read_struct (&png, NULL, NULL);
png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL,
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);
if (!end_info){
png_destroy_read_struct (&png, &info_ptr, 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->jmpbuf)){
png_destroy_read_struct (&png, &info_ptr, &end_info);
if (setjmp(png_ptr->jmpbuf)) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
png_init_io (pngptr, f);
png_init_io(png_ptr, f);
png_read_info(png_ptr, info_ptr);
png_read_info (png, info_ptr);
png_get_IHDR (png, info_ptr, &width, &height, &depth, &color_type, &interlace_type, NULL, NULL);
png_get_IHDR(png_ptr, info_ptr, &w, &h, &depth, &ctype, &inttype,
NULL, NULL);
if (color_type == color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand (png);
/*
* Strip 16 bit information to 8 bit
/* Ok, we want to work with 24 bit images.
* However, PNG can vary depth per channel.
* So, we use the png_set_expand function to expand
* everything into a format libart expects.
* We also use png_set_strip_16 to reduce down to 8 bit/chan.
*/
png_set_strip_16 (png);
/*
* Extract multiple pixels with bit depths 1, 2 and 4 from a single
* byte into separate bytes
*/
png_set_packing (png);
if (ctype == PNG_COLOR_TYPE_PALETTE && depth <= 8)
png_set_expand(png_ptr);
/*
* Makes the PNG file to be rendered into RGB or RGBA
* modes (no matter of the bit depth nor the image
* mode
*/
png_set_expand (png);
if (ctype == PNG_COLOR_TYPE_GRAY && depth < 8)
png_set_expand(png_ptr);
/*
* Simplify loading by always having 4 bytes
*/
png_set_filler (png, 0xff, PNG_FILLER_AFTER);
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
png_set_expand(png_ptr);
if (color_type & PNG_COLOR_MASK_ALPHA)
have_alpha = 1
else
have_alpha = 0;
data = art_alloc (width * height * (3 + have_alpha));
if (!data){
png_destroy_read_struct (&png, &info_ptr, &end_info);
if (depth == 16)
png_set_strip_16(png_ptr);
/* We also have png "packing" bits into bytes if < 8 */
if (depth < 8)
png_set_packing(png_ptr);
/* Add filler bits to non-alpha PNGs */
/* make it 255, full opaque */
if (depth == 8 && ctype == PNG_COLOR_TYPE_RGB)
png_set_filler(png_ptr, 0xFF, PNG_FILLER_AFTER);
/* Lastly, if the PNG is greyscale, convert to RGB */
if (ctype == PNG_COLOR_TYPE_GRAY || ctype == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png_ptr);
/* ...and if we're interlaced... */
passes = png_set_interlace_handling(png_ptr);
/* Update our info structs */
png_read_update_info(png_ptr, info_ptr);
/* Allocate some memory and set up row array */
/* This "inhales vigirously"... */
pixels = g_malloc(w*h*4);
rows = g_malloc(h*sizeof(png_bytep));
if ((!pixels) || (!rows)) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
number_passes = png_set_interlace_handling (png);
/* Icky code, but it has to be done... */
for (i = 0; i < h; i++) {
if ((rows[i] = g_malloc(w*sizeof(art_u8)*4)) == NULL) {
int n;
for (n = 0; n < i; n++)
g_free(rows[i]);
g_free(rows);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
return NULL;
}
}
/* And we FINALLY get here... */
png_read_image(png_ptr, rows);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
/* Now stuff the bytes into pixels & free rows[y] */
/* RGBA order */
temp = pixels;
for (y = 0; y < h; y++) {
(png_bytep)rowdata = rows[y];
for (x = 0; x < w; x++) {
temp[0] = rowdata[(x*4)];
temp[1] = rowdata[(x*4)+1];
temp[2] = rowdata[(x*4)+2];
temp[3] = rowdata[(x*4)+3];
temp += 4;
}
g_free(rows[y]);
}
g_free(rows);
/* Return the GdkPixBuf */
pixbuf = g_new(GdkPixBuf, 1);
pixbuf->art_pixbuf = art_pixbuf_new_rgba (pixels, w, h, (w*4));
/* Ok, I'm anal...shoot me */
if (!(pixbuf->art_pixbuf))
return NULL;
pixbuf->ref_count = 0;
pixbuf->unref_func = NULL;
return pixbuf;
}
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