add offset() operation to OpenLayers.Pixel

git-svn-id: http://svn.openlayers.org/trunk/openlayers@444 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -66,6 +66,17 @@ OpenLayers.Pixel.prototype = {
         return new OpenLayers.Pixel(this.x + x, this.y + y);
     },
 
+    /**
+    * @param {OpenLayers.Pixel} px
+    * 
+    * @return a new Pixel with this pixel's x&y augmented by the 
+    *         x&y values of the pixel passed in.
+    * @type OpenLayers.Pixel
+    */
+    offset:function(px) {
+        return this.add(px.x, px.y);                
+    },
+    
     /** @final @type str */
     CLASS_NAME: "OpenLayers.Pixel"
 };

tests/test_Pixel.html

@@ -61,6 +61,21 @@
         t.eq( pixel.y, 26, "pixel.y is set correctly");
     }
 
+    function test_08_Pixel_offset(t) {
+        t.plan( 4 );
+
+        var oldPixel = new OpenLayers.Pixel(5,6);
+        var offset = new OpenLayers.Pixel(10,20);
+
+        pixel = oldPixel.offset(offset);
+
+        t.eq( oldPixel.x, 5, "oldPixel.x not modified by offset operation");
+        t.eq( oldPixel.y, 6, "oldPixel.y not modified by offset operation");
+
+        t.eq( pixel.x, 15, "pixel.x is set correctly");
+        t.eq( pixel.y, 26, "pixel.y is set correctly");
+    }
+
   // -->
   </script>
 </head>