- #88, MFB: Bug loading png images in grayscale + alpha

- add test

src/gd_png.c

@@ -195,7 +195,8 @@ BGD_DECLARE(gdImagePtr) gdImageCreateFromPngCtx (gdIOCtx * infile)
 	png_read_info (png_ptr, info_ptr);	/* read all PNG info up to image data */
 
 	png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, NULL, NULL);
-	if ((color_type == PNG_COLOR_TYPE_RGB) || (color_type == PNG_COLOR_TYPE_RGB_ALPHA)) {
+	if ((color_type == PNG_COLOR_TYPE_RGB) || (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+		|| color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
 		im = gdImageCreateTrueColor ((int) width, (int) height);
 	} else {
 		im = gdImageCreate ((int) width, (int) height);
@@ -258,7 +259,6 @@ BGD_DECLARE(gdImagePtr) gdImageCreateFromPngCtx (gdIOCtx * infile)
 			break;
 
 		case PNG_COLOR_TYPE_GRAY:
-		case PNG_COLOR_TYPE_GRAY_ALPHA:
 			/* create a fake palette and check for single-shade transparency */
 			if ((palette = (png_colorp) gdMalloc (256 * sizeof (png_color))) == NULL) {
 				fprintf (stderr, "gd-png error: cannot allocate gray palette\n");
@@ -298,6 +298,9 @@ BGD_DECLARE(gdImagePtr) gdImageCreateFromPngCtx (gdIOCtx * infile)
 			}
 			break;
 
+		case PNG_COLOR_TYPE_GRAY_ALPHA:
+			png_set_gray_to_rgb(png_ptr);
+
 		case PNG_COLOR_TYPE_RGB:
 		case PNG_COLOR_TYPE_RGB_ALPHA:
 			/* gd 2.0: we now support truecolor. See the comment above
@@ -396,6 +399,8 @@ BGD_DECLARE(gdImagePtr) gdImageCreateFromPngCtx (gdIOCtx * infile)
 				}
 			}
 			break;
+
+		case PNG_COLOR_TYPE_GRAY_ALPHA:
 		case PNG_COLOR_TYPE_RGB_ALPHA:
 			for (h = 0; h < height; h++) {
 				int boffset = 0;

tests/png/CMakeLists.txt

@@ -3,6 +3,7 @@ SET(TESTS_FILES
 	bug00011
 	bug00033
 	bug00086
+	bug00088
 )
 
 FOREACH(test_name ${TESTS_FILES})

tests/png/bug00088.c

@@ -0,0 +1,44 @@
+/* $Id$ */
+#include "gd.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "gdtest.h"
+
+int main()
+{
+	int error;
+ 	gdImagePtr im;
+	FILE *fp;
+	char path[1024];
+	const char * files[2] = {"bug00088_1.png", "bug00088_2.png"};
+	const char * files_exp[2] = {"bug00088_1_exp.png", "bug00088_2_exp.png"};
+
+	int i, cnt = 2;
+	error = 0;
+
+	for (i = 0; i < cnt; i++) {
+
+		sprintf(path, "%s/png/%s", GDTEST_TOP_DIR, files[i]);
+		fp = fopen(path, "rb");
+		if (!fp) {
+			printf("failed, cannot open file <%s>\n", path);
+			return 1;
+		}
+
+		im = gdImageCreateFromPng(fp);
+		fclose(fp);
+
+		if (!im) {
+			error |= 1;
+			continue;
+		}
+
+		sprintf(path, "%s/png/%s", GDTEST_TOP_DIR, files_exp[i]);
+		if (!gdAssertImageEqualsToFile(path, im)) {
+			error |= 1;
+		}
+		gdImageDestroy(im);
+	}
+
+	return error;
+}