Util methods for animation loops.

lib/OpenLayers/Util.js

@@ -1697,3 +1697,40 @@ OpenLayers.Util.getFormattedLonLat = function(coordinate, axis, dmsOption) {
     return str;
 };
 
+OpenLayers.Util.requestAnimationFrame = (function() {
+    return window.requestAnimationFrame ||
+        window.webkitRequestAnimationFrame ||
+        window.mozRequestAnimationFrame ||
+        window.oRequestAnimationFrame ||
+        window.msRequestAnimationFrame ||
+        function(callback, element) {
+            window.setTimeout(callback, 16);
+        };
+})();
+
+(function() {
+
+    var counter = 0;
+    var loops = {};
+    var request = OpenLayers.Util.requestAnimationFrame;
+    
+    OpenLayers.Util.loopAnimation = function(duration, callback, element) {
+        var id = ++counter;
+        var start = +new Date;
+        loops[id] = function() {
+            if (loops[id] && +new Date - start <= duration) {
+                callback();
+                request(loops[id], element);
+            } else {
+                delete loops[id];
+            }
+        }
+        request(loops[id], element);
+        return id;
+    }
+    
+    OpenLayers.Util.stopAnimation = function(id) {
+        delete loops[id];
+    }
+    
+})();