Use existing methods on XYZ layer.

lib/OpenLayers/Layer/UTFGrid.js

@@ -4,17 +4,16 @@
  * full text of the license. */
 
 /**
- * @requires OpenLayers/Layer/Grid.js
+ * @requires OpenLayers/Layer/XYZ.js
  * @requires OpenLayers/Tile/UTFGrid.js
  */
 
 /** 
  * Class: OpenLayers.Layer.UTFGrid
- * This Layer reads from UTFGrid tiled data sources. 
+ * This Layer reads from UTFGrid tiled data sources.  Since UTFGrids are 
- * Since UTFGrids are essentially JSON-based ASCII art 
+ * essentially JSON-based ASCII art with attached attributes, they are not 
- * with attached attributes, they are not visibly rendered. 
+ * visibly rendered.  In order to use them in the map, you must add a 
- * In order to use them in the map, 
+ * <OpenLayers.Control.UTFGrid> ontrol as well.
- * you must add a UTFGrid Control as well.
  *
  * Example:
  *
@@ -37,9 +36,9 @@
  *
  * 
  * Inherits from:
- *  - <OpenLayers.Layer.Grid>
+ *  - <OpenLayers.Layer.XYZ>
  */
-OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
+OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.XYZ, {
     
     /**
      * APIProperty: isBaseLayer
@@ -54,36 +53,6 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
      */
     projection: new OpenLayers.Projection("EPSG:900913"),
 
-    /**
-     * APIProperty: zoomOffset
-     * {Number} If your cache has more zoom levels than you want to provide
-     *     access to with this layer, supply a zoomOffset.  This zoom offset
-     *     is added to the current map zoom level to determine the level
-     *     for a requested tile.  For example, if you supply a zoomOffset
-     *     of 3, when the map is at the zoom 0, tiles will be requested from
-     *     level 3 of your cache.  Default is 0 (assumes cache level and map
-     *     zoom are equivalent).  Using <zoomOffset> is an alternative to
-     *     setting <serverResolutions> if you only want to expose a subset
-     *     of the server resolutions.
-     */
-    zoomOffset: 0,
-    
-    /**
-     * APIProperty: serverResolutions
-     * {Array} A list of all resolutions available on the server.  Only set this
-     *     property if the map resolutions differ from the server. This
-     *     property serves two purposes. (a) <serverResolutions> can include
-     *     resolutions that the server supports and that you don't want to
-     *     provide with this layer; you can also look at <zoomOffset>, which is
-     *     an alternative to <serverResolutions> for that specific purpose.
-     *     (b) The map can work with resolutions that aren't supported by
-     *     the server, i.e. that aren't in <serverResolutions>. When the
-     *     map is displayed in such a resolution data for the closest
-     *     server-supported resolution is loaded and the layer div is
-     *     stretched as necessary.
-     */
-    serverResolutions: null,
-
     /**
      * Property: useJSONP
      * {Boolean}
@@ -160,28 +129,6 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
         obj = OpenLayers.Layer.Grid.prototype.clone.apply(this, [obj]);
 
         return obj;
-    },    
-
-    /**
-     * Method: getURL
-     *
-     * Parameters:
-     * bounds - {<OpenLayers.Bounds>}
-     *
-     * Returns:
-     * {String} A string with the layer's url and parameters and also the
-     *          passed-in bounds and appropriate tile size specified as
-     *          parameters
-     */
-    getURL: function (bounds) {
-        var xyz = this.getXYZ(bounds);
-        var url = this.url;
-        if (OpenLayers.Util.isArray(url)) {
-            var s = '' + xyz.x + xyz.y + xyz.z;
-            url = this.selectUrl(s, url);
-        }
-        
-        return OpenLayers.String.format(url, xyz);
     },
 
     /** 
@@ -295,53 +242,5 @@ OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.Grid, {
         return id;
     },
 
-
-    /**
-     * Method: getXYZ
-     * Calculates x, y and z for the given bounds.
-     *
-     * Parameters:
-     * bounds - {<OpenLayers.Bounds>}
-     *
-     * Returns:
-     * {Object} - an object with x, y and z properties.
-     */
-    getXYZ: function(bounds) {
-        var res = this.getServerResolution();
-        var x = Math.round((bounds.left - this.maxExtent.left) /
-            (res * this.tileSize.w));
-        var y = Math.round((this.maxExtent.top - bounds.top) /
-            (res * this.tileSize.h));
-        var resolutions = this.serverResolutions || this.resolutions;
-        var z = this.getServerZoom();
-        if (this.zoomOffset > 0) {
-            z += this.zoomOffset;
-        }
-
-        var limit = Math.pow(2, z);
-        if (this.wrapDateLine)
-        {
-           x = ((x % limit) + limit) % limit;
-        }
-
-        return {'x': x, 'y': y, 'z': z};
-    },
-    
-    /**
-     * Method: setMap
-     * When the layer is added to a map, then we can fetch our origin 
-     *    (if we don't have one.) 
-     * 
-     * Parameters:
-     * map - {<OpenLayers.Map>}
-     */
-    setMap: function(map) {
-        OpenLayers.Layer.Grid.prototype.setMap.apply(this, arguments);
-        if (!this.tileOrigin) { 
-            this.tileOrigin = new OpenLayers.LonLat(this.maxExtent.left,
-                                                this.maxExtent.top);
-        }                                       
-    },
-
     CLASS_NAME: "OpenLayers.Layer.UTFGrid"
 });