Merge branch 'get-intersection-cache' of git://github.com/vmichnowicz/KineticJS into vmichnowicz-get-intersection-cache

Conflicts:
	src/Container.js
	src/Shape.js

src/Container.js

@@ -307,6 +307,9 @@
                 cachedHitCanvas = cachedCanvas && cachedCanvas.hit;
 
             if (this.shouldDrawHit(canvas)) {
+                if (layer) {
+                    layer.imageData = null; // Clear getImageData cache
+                }
                 if (cachedHitCanvas) {
                     this._drawCachedHitCanvas(context);
                 }

src/Layer.js

@@ -92,8 +92,32 @@
                 return null;
             }
         },
+        /**
+         * Get ImageData.data array for an individual pixel on the hit canvas.
+         * Data is cached as getImageData is an expensive method to call often.
+         *
+         * @param {Number} x
+         * @param {Number} x
+         * @returns {Array} One-dimensional array containing the data in the RGBA order, with integer values between 0 and 255
+         */
+        _getImageData: function(x, y) {
+            var width = this.hitCanvas.width || 1,
+                height = this.hitCanvas.height || 1,
+                index = (y * width ) + x;
+
+            if (!this.imageData) {
+                this.imageData = this.hitCanvas.context._context.getImageData(0, 0, width, height);
+            }
+
+            return [
+                this.imageData.data[4 * index + 0] , // Red
+                this.imageData.data[4 * index + 1], // Green
+                this.imageData.data[4 * index + 2], // Blue
+                this.imageData.data[4 * index + 3] // Alpha
+            ];
+        },
         _getIntersection: function(pos) {
-            var p = this.hitCanvas.context._context.getImageData(pos.x, pos.y, 1, 1).data,
+            var p = this._getImageData(pos.x, pos.y),
                 p3 = p[3],
                 colorKey, shape;
 
@@ -170,6 +194,7 @@
         clear: function(bounds) {
             this.getContext().clear(bounds);
             this.getHitCanvas().getContext().clear(bounds);
+            this.imageData = null; // Clear getImageData cache
             return this;
         },
         // extend Node.prototype.setVisible

src/Shape.js

@@ -209,7 +209,9 @@
                 cachedHitCanvas = cachedCanvas && cachedCanvas.hit;
 
             if(this.shouldDrawHit(canvas)) {
-                
+                if (layer) {
+                    layer.imageData = null; // Clear getImageData cache
+                }
                 if (cachedHitCanvas) {
                     this._drawCachedHitCanvas(context);
                 }