Add Raster#loaded to reflect the loading state of its image.

CHANGELOG.md

@@ -171,6 +171,7 @@ contribute to the code.
 - Add `tolerance` argument to `Path#join(path, tolerance)`.
 - Add `Curve#getOffsetAtTime(time)`, as the reverse of
   `Curve#getTimeAt(offset)`.
+- Add `Raster#loaded` to reflect the loading state of its image.
 
 ### Fixed
 - Fix calculations of `Item#strokeBounds` for all possible combinations of

src/item/Raster.js

@@ -181,6 +181,16 @@ var Raster = Item.extend(/** @lends Raster# */{
         this.setSize(this.getWidth(), height);
     },
 
+    /**
+     * The loading state of the raster image.
+     *
+     * @bean
+     * @type Boolean
+     */
+    getLoaded: function() {
+        return this._loaded;
+    },
+
     isEmpty: function() {
         var size = this._size;
         return !size || size.width === 0 && size.height === 0;