png: enable loading of RGBA images

Sebastien Bourdeauducq · Sebastien Bourdeauducq · commit 031740c39fd1 · 2011-11-29T14:55:57.000+01:00
diff --git a/src/pixbuf/dither.c b/src/pixbuf/dither.c
@@ -82,7 +82,7 @@ static void floyd_steinberg(int *pic, int width, int height)
 		}
 }
 
-int pixbuf_dither(unsigned short *ret, unsigned char **row_pointers, int width, int height)
+int pixbuf_dither(unsigned short *ret, unsigned char **row_pointers, int width, int height, int has_alpha)
 {
 	int x, y;
 	unsigned char *row;
@@ -92,13 +92,25 @@ int pixbuf_dither(unsigned short *ret, unsigned char **row_pointers, int width,
 	pic = malloc(width*height*3*sizeof(int));
 	if(pic == NULL) return 0;
 	
-	for(y=0;y<height;y++) {
-		row = row_pointers[y];
-		for(x=0;x<width;x++) {
-			offset = 3*(width*y+x);
-			pic[offset] = ((unsigned int)row[3*x]) << 16;
-			pic[offset+1] = ((unsigned int)row[3*x+1]) << 16;
-			pic[offset+2] = ((unsigned int)row[3*x+2]) << 16;
+	if(has_alpha) {
+		for(y=0;y<height;y++) {
+			row = row_pointers[y];
+			for(x=0;x<width;x++) {
+				offset = 3*(width*y+x);
+				pic[offset] = ((unsigned int)row[4*x]) << 16;
+				pic[offset+1] = ((unsigned int)row[4*x+1]) << 16;
+				pic[offset+2] = ((unsigned int)row[4*x+2]) << 16;
+			}
+		}
+	} else {
+		for(y=0;y<height;y++) {
+			row = row_pointers[y];
+			for(x=0;x<width;x++) {
+				offset = 3*(width*y+x);
+				pic[offset] = ((unsigned int)row[3*x]) << 16;
+				pic[offset+1] = ((unsigned int)row[3*x+1]) << 16;
+				pic[offset+2] = ((unsigned int)row[3*x+2]) << 16;
+			}
 		}
 	}
 	
diff --git a/src/pixbuf/dither.h b/src/pixbuf/dither.h
@@ -18,6 +18,6 @@
 #ifndef __PIXBUF_DITHER_H
 #define __PIXBUF_DITHER_H
 
-int pixbuf_dither(unsigned short *ret, unsigned char **row_pointers, int width, int height);
+int pixbuf_dither(unsigned short *ret, unsigned char **row_pointers, int width, int height, int has_alpha);
 
 #endif /* __PIXBUF_DITHER_H */
diff --git a/src/pixbuf/loaderjpeg.c b/src/pixbuf/loaderjpeg.c
@@ -75,7 +75,7 @@ struct pixbuf *pixbuf_load_jpeg(char *filename)
 
 	ret = pixbuf_new(cinfo.image_width, cinfo.image_height);
 	if(ret == NULL) goto free5;
-	if(!pixbuf_dither(ret->pixels, row_pointers, cinfo.image_width, cinfo.image_height)) {
+	if(!pixbuf_dither(ret->pixels, row_pointers, cinfo.image_width, cinfo.image_height, 0)) {
 		pixbuf_dec_ref(ret);
 		ret = NULL;
 		goto free5;
diff --git a/src/pixbuf/loaderpng.c b/src/pixbuf/loaderpng.c
@@ -64,7 +64,7 @@ struct pixbuf *pixbuf_load_png(char *filename)
 	color_type = png_get_color_type(png_ptr, info_ptr);
 	bit_depth = png_get_bit_depth(png_ptr, info_ptr);
 
-	if(color_type != PNG_COLOR_TYPE_RGB) goto free3;
+	if((color_type != PNG_COLOR_TYPE_RGB) && (color_type != PNG_COLOR_TYPE_RGBA)) goto free3;
 	if(bit_depth != 8) goto free3;
 
 	row_pointers = calloc(sizeof(png_bytep), height);
@@ -82,7 +82,7 @@ struct pixbuf *pixbuf_load_png(char *filename)
 	ret = pixbuf_new(width, height);
 	if(ret == NULL) goto free4;
 	ret->filename = strdup(filename);
-	if(!pixbuf_dither(ret->pixels, row_pointers, width, height)) {
+	if(!pixbuf_dither(ret->pixels, row_pointers, width, height, color_type == PNG_COLOR_TYPE_RGBA)) {
 		pixbuf_dec_ref(ret);
 		ret = NULL;
 		goto free4;
