a "big back buffer" attempt

lib/OpenLayers/Tile/Image.js

@@ -17,7 +17,7 @@
  * Inherits from:
  *  - <OpenLayers.Tile.BackBufferable>
  */
-OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
+OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
 
     /** 
      * Property: url
@@ -96,7 +96,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
      * options - {Object}
      */   
     initialize: function(layer, position, bounds, url, size, options) {
-        OpenLayers.Tile.BackBufferable.prototype.initialize.apply(this, arguments);
+        OpenLayers.Tile.prototype.initialize.apply(this, arguments);
 
         this.url = url; //deprecated remove me
 
@@ -123,7 +123,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
         }
         // don't handle async requests any more
         this.asyncRequestId = null;
-        OpenLayers.Tile.BackBufferable.prototype.destroy.apply(this, arguments);
+        OpenLayers.Tile.prototype.destroy.apply(this, arguments);
     },
     
     /**
@@ -134,7 +134,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
      * {Boolean} Was a tile drawn?
      */
     draw: function() {
-        var drawn = OpenLayers.Tile.BackBufferable.prototype.draw.apply(this, arguments);
+        var drawn = OpenLayers.Tile.prototype.draw.apply(this, arguments);
         if (drawn) {
             if (this.layer != this.layer.map.baseLayer && this.layer.reproject) {
                 this.bounds = this.getBoundsFromBaseLayer(this.position);
@@ -335,6 +335,16 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
         return frame;
     },
 
+    cloneMarkup: function() {
+        if(!this.imgDiv || this.isLoading) {
+            return;
+        }
+        var clone = this.frame.cloneNode(false);
+        clone.appendChild(this.imgDiv);
+        this.imgDiv = null;
+        return clone;
+    },
+
     /**
      * Method: onImageLoad
      * Handler for the image onload event