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.

diff --git a/gdk-pixbuf/io-png.c b/gdk-pixbuf/io-png.c
index 414ef45e764dac69ea538c181b1f127510e0d988..a1fef8dfbf6efb8ee3450b0118023eb749ced2f8 100644 (file)
--- a/gdk-pixbuf/io-png.c
+++ b/gdk-pixbuf/io-png.c
@@ -1,90 +1,146 @@
 /*
- * 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;
 }