1 files changed, 92 insertions, 0 deletions
diff --git a/tests/avif/compare_avif_to_png.c b/tests/avif/compare_avif_to_png.c
new file mode 100644
index 0000000..6330ea3
--- /dev/null
+++ b/tests/avif/compare_avif_to_png.c
@@ -0,0 +1,92 @@
+/**
+ * File: compare_avif_to_png
+ *
+ * Thorough check for AVIF encoding and decoding.
+ * This test reqiures a set of PNG images that have been losslessly encoded to AVIFs.
+ * For each such image, we encode the PNG into an AVIF, with the GD format as an intermediary,
+ * then compare the resulting AVIF with the original PNG.
+ *
+ * We then do this process in reverse, encoding the AVIF into a PNG,
+ * and compare the resulting PNG with the original AVIF.
+ *
+ * We report any discrepancies in the images, or any other errors that may occur.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include "gd.h"
+#include "gdtest.h"
+
+int main() {
+	FILE *fp;
+	gdImagePtr imFromPng = NULL, imFromAvif = NULL;
+	void *avifImDataPtr = NULL, *pngImDataPtr = NULL;
+	int size;
+	char pngFilename[100], avifFilename[100], *pngFilePath;
+	char errMsg[4096];
+
+	static const char * const filenames[] = {"baboon", "dice_with_alpha", "plum_blossom_12bit", "sunset"};
+	const int filesCount = sizeof(filenames) / sizeof(filenames[0]);
+
+	for (int i = 0; i < filesCount; i++) {
+
+		// First, encode each PNG into an AVIF (with the GD format as an intermediary),
+		// then compare the result with the original PNG.
+		sprintf(pngFilename, "%s.png", filenames[i]);
+
+		fp = gdTestFileOpen2("avif", pngFilename);
+		imFromPng = gdImageCreateFromPng(fp);
+		fclose(fp);
+
+		strcat(strcpy(errMsg, filenames[i]), ".png: gdImageCreateFromPng failed\n");
+		if (!gdTestAssertMsg(imFromPng != NULL, errMsg))
+			goto avif2png;
+
+		strcat(strcpy(errMsg, filenames[i]), ": gdImageAvifPtrEx failed\n");
+		avifImDataPtr = gdImageAvifPtrEx(imFromPng, &size, 100, 0);
+		if (!gdTestAssertMsg(avifImDataPtr != NULL, errMsg))
+			goto avif2png;
+
+		strcat(strcpy(errMsg, filenames[i]), ": gdImageCreateFromAvifPtr failed\n");
+		imFromAvif = gdImageCreateFromAvifPtr(size, avifImDataPtr);
+		if (!gdTestAssertMsg(imFromAvif != NULL, errMsg))
+			goto avif2png;
+
+		strcat(strcpy(errMsg, filenames[i]), ".png: Encoded AVIF image did not match original PNG\n");
+		gdTestAssertMsg(gdAssertImageEquals(imFromPng, imFromAvif), errMsg);
+
+		// Then, decode each AVIF into a GD format, and compare that with the orginal PNG.
+avif2png:
+
+		// Skip this reverse test for now, until we can find images that encode to PNGs losslessly.
+if (0) {
+		sprintf(avifFilename, "%s.avif", filenames[i]);
+		fp = gdTestFileOpen2("avif", avifFilename);
+		imFromAvif = gdImageCreateFromAvif(fp);
+		fclose(fp);
+
+		strcat(strcpy(errMsg, filenames[i]), ".avif: gdImageCreateFromAvif failed\n");
+		if (!gdTestAssertMsg(imFromAvif != NULL, errMsg))
+			continue;
+
+		strcat(strcpy(errMsg, filenames[i]), ".avif: Encoded PNG image did not match original AVIF\n");
+		pngFilePath = gdTestFilePath2("avif", pngFilename);
+		gdTestAssertMsg(gdAssertImageEqualsToFile(pngFilePath, imFromAvif), errMsg);
+		free(pngFilePath);
+}
+	}
+
+	if (imFromPng)
+		gdImageDestroy(imFromPng);
+
+	if (imFromAvif)
+		gdImageDestroy(imFromAvif);
+
+	if (avifImDataPtr)
+		gdFree(avifImDataPtr);
+
+	if (pngImDataPtr)
+		gdFree(pngImDataPtr);
+
+	return gdNumFailures();
+}