Add image scale example

2 files changed, 83 insertions, 1 deletions

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 70282c7..5b0d99d 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -8,7 +8,7 @@ if (PNG_FOUND)
 	LIST(APPEND TEST_FILES arc crop tgaread)
 
 	if (JPEG_FOUND)
-		LIST(APPEND TESTS_FILES copyrotated flip nnquant)
+		LIST(APPEND TESTS_FILES copyrotated flip nnquant imagescale)
 	endif (JPEG_FOUND)
 endif (PNG_FOUND)
 
diff --git a/examples/imagescale.c b/examples/imagescale.c
new file mode 100644
index 0000000..d23e172
--- /dev/null
+++ b/examples/imagescale.c
@@ -0,0 +1,82 @@
+/* Exercise all scaling with all interpolation modes and ensure that
+ * at least, something comes back. */
+
+#include <stdio.h>
+
+#include "gd.h"
+
+#define X 100
+#define Y 100
+
+#define NX 100
+#define NY 100
+
+gdImagePtr loadImage(const char *name)
+{
+	FILE *fp;
+	gdImagePtr im;
+
+	fp = fopen(name, "rb");
+	if (!fp) {
+		fprintf(stderr, "Can't open jpeg file\n");
+		return NULL;
+	}
+
+	im = gdImageCreateFromPng(fp);
+	fclose(fp);
+	return im;
+}
+
+int savePngImage(gdImagePtr im, const char *name)
+{
+	FILE *fp;
+	fp = fopen(name, "wb");
+	if (!fp) {
+		fprintf(stderr, "Can't save png image fromtiff.png\n");
+		return 0;
+	}
+	gdImagePng(im, fp);
+	fclose(fp);
+	return 1;
+}
+
+int main() {
+    unsigned int method;
+    gdImagePtr src;
+    src = loadImage("fillandstroke.png");
+    if (!src) {
+        printf("cannot open src image");
+        exit(1);
+    }
+    int new_width = gdImageSX(src) *3;
+    int new_height = gdImageSY(src) *3;
+    for(method = GD_DEFAULT; method < GD_METHOD_COUNT; method++) {   /* GD_WEIGHTED4 is unsupported. */
+        gdImagePtr result;
+        if (method == GD_WEIGHTED4) {
+            continue;
+        }
+
+        gdImageSetInterpolationMethod(src, method);
+        printf("arg %i set: %i get %i\n", method, src->interpolation_id, gdImageGetInterpolationMethod(src));
+
+        result = gdImageScale(src, new_width, new_height);
+        if (result == NULL) {
+            printf("gdImageScale failed (method: %i).\n", method);
+            break;
+        }
+        if (result->sx != new_width || result->sy != new_height) {
+            printf("missmatch width or height\n");
+            gdImageDestroy(result);
+            gdImageDestroy(src);
+            exit(1);
+        }
+
+        char filename[255];
+        sprintf(filename, "scale_%i.png", method);
+        savePngImage(result, filename);
+        gdImageDestroy(result);
+    }/* for*/
+    gdImageDestroy(src);
+
+    return 0;
+}