Fix a problem determining zoom levels. Updated some docs.

lib/OpenLayers/Tile/UTFGrid.js

@@ -11,7 +11,9 @@
 /**
  * Class: OpenLayers.Tile.UTFGrid
  * Instances of OpenLayers.Tile.UTFGrid are used to manage the image tiles
- * TODO
+ * MP TODO
+ * IMPORTANT - remove all traces of IMAGES
+ *
  * <OpenLayers.Tile.UTFGrid> constructor.
  *
  * Inherits from:
@@ -69,6 +71,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
     /** 
      * APIMethod: destroy
      * nullify references to prevent circular references and memory leaks
+     * MP TODO what do we need to clear for the utfgrid implementation?
      */
     destroy: function() {
         if (this.imgDiv)  {
@@ -90,6 +93,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
      */
     draw: function() {
         var drawn = OpenLayers.Tile.prototype.draw.apply(this, arguments);
+        console.log(drawn);
         if (drawn) {
             if (this.isLoading) {
                 //if we're already loading, send 'reload' instead of 'loadstart'.
@@ -108,7 +112,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
             });
 
             /*
-             * TODO Investigate JSONP method to avoid xbrowser polucy
+             * MP TODO Investigate JSONP method to avoid xbrowser polucy
              *
             grid = function(e) { 
                 console.log(e);
@@ -122,9 +126,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
             var res = ols.read();
             console.log(res.priv);
             */
-
             this.positionTile();
-            //this.renderTile();
         } else {
             this.unload();
         }
@@ -145,31 +147,6 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
         } 
     },
     
-    /**
-     * Method: renderTile
-     * Internal function to actually initialize the image tile,
-     *     position it correctly, and set its url.
-     */
-    renderTile: function() {
-        this.layer.div.appendChild(this.getTile());
-        if (this.layer.async) {
-            // Asynchronous image requests call the asynchronous getURL method
-            // on the layer to fetch an image that covers 'this.bounds', in the scope of
-            // 'this', setting the 'url' property of the layer itself, and running
-            // the callback 'initImage' when the image request returns.
-            var myId = this.asyncRequestId = (this.asyncRequestId || 0) + 1;
-            this.layer.getURLasync(this.bounds, this, "url", function() {
-                if (myId == this.asyncRequestId) {
-                    this.initImage();
-                }
-            });
-        } else {
-            // synchronous image requests get the url immediately.
-            this.url = this.layer.getURL(this.bounds);
-            this.initImage();
-        }
-    },
-
     /**
      * Method: positionTile
      * Using the properties currenty set on the layer, position the tile correctly.
@@ -186,6 +163,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
 
     /** 
      * Method: clear
+     * MP TODO remove the json from the DOM!
      * Remove the tile from the DOM, clear it of any image related data so that
      * it can be reused in a new location.
      */