Merge pull request #84 from walterbm/thumbnail-resize

Add support for "thumbnail" image resizing

src/wand/magick.rs

@@ -691,6 +691,15 @@ impl MagickWand {
         }
     }
 
+    /// Resize the image to the specified width and height, using the
+    /// 'thumbnail' optimizations which remove a lot of image meta-data with the goal 
+    /// of producing small low cost images suited for display on the web.
+    pub fn thumbnail_image(&self, width: usize, height: usize) {
+        unsafe {
+            bindings::MagickThumbnailImage(self.wand, width as size_t, height as size_t);
+        }
+    }
+
     /// Extract a region of the image. The width and height is used as the size
     /// of the region. X and Y is the offset.
     pub fn crop_image(

tests/lib.rs

@@ -59,6 +59,29 @@ fn test_resize_image() {
     assert_eq!(192, wand.get_image_height());
 }
 
+#[test]
+fn test_thumbnail_image() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+    assert!(wand.read_image("tests/data/IMG_5745.JPG").is_ok());
+    assert_eq!(512, wand.get_image_width());
+    assert_eq!(384, wand.get_image_height());
+    let halfwidth = match wand.get_image_width() {
+        1 => 1,
+        width => width / 2,
+    };
+    let halfheight = match wand.get_image_height() {
+        1 => 1,
+        height => height / 2,
+    };
+    wand.thumbnail_image(halfwidth, halfheight);
+    assert_eq!(256, wand.get_image_width());
+    assert_eq!(192, wand.get_image_height());
+}
+
+
 #[test]
 fn test_read_from_blob() {
     START.call_once(|| {