add HEIC example

examples/CMakeLists.txt

@@ -20,6 +20,10 @@ if (TIFF_FOUND)
 	LIST(APPEND TESTS_FILES	tiffread)
 endif (TIFF_FOUND)
 
+if (HEIF_FOUND)
+	LIST(APPEND TESTS_FILES	png2heif)
+endif (HEIF_FOUND)
+
 if (BUILD_SHARED_LIBS)
 	set(GD_LINK_LIB ${GD_LIB})
 else()

examples/png2heif.c

@@ -0,0 +1,63 @@
+/**
+ * A short program which converts a .png file into a .avif file -
+ * just to get a little practice with the basic functionality.
+ * We convert losslessly.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "gd.h"
+
+int main(int argc, char **argv)
+{
+	gdImagePtr im;
+	FILE *in, *out;
+
+	if (argc != 3) {
+		fprintf(stderr, "Usage: png2avif infile.png outfile.avif\n");
+		exit(1);
+	}
+
+	printf("Reading infile %s\n", argv[1]);
+
+	in = fopen(argv[1], "rb");
+	if (!in) {
+		fprintf(stderr, "Error: input file %s does not exist.\n", argv[1]);
+		exit(1);
+	}
+
+	im = gdImageCreateFromPng(in);
+	fclose(in);
+	if (!im) {
+		fprintf(stderr, "Error: input file %s is not in PNG format.\n", argv[1]);
+		exit(1);
+	}
+	gdImagePaletteToTrueColor(im);
+	if (!gdImagePaletteToTrueColor(im)) {
+		gdImageDestroy(im);
+		exit(1);
+	}
+
+	out = fopen(argv[2], "wb");
+	if (!out) {
+		fprintf(stderr, "Error: can't write to output file %s\n", argv[2]);
+		gdImageDestroy(im);
+		exit(1);
+	}
+
+	fprintf(stderr, "Encoding...\n");
+
+	gdImageHeif(im, out);
+
+	printf("Wrote outfile %s.\n", argv[2]);
+
+	fclose(out);
+	gdImageDestroy(im);
+
+	return 0;
+}