Merge pull request #130 from fredj/tile-class

OpenLayers.Layer.Grid: ability to change the tile types. r=tschaub

lib/OpenLayers/Layer/Grid.js

@@ -50,6 +50,13 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      *  created by this Layer, if supported by the tile class.
      */
     tileOptions: null,
+
+    /**
+     * APIProperty: tileClass
+     * {<OpenLayers.Tile>} The tile class to use for this layer.
+     *     Defaults is OpenLayers.Tile.Image.
+     */
+    tileClass: OpenLayers.Tile.Image,
     
     /**
      * Property: grid
@@ -900,9 +907,9 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      * Returns:
      * {<OpenLayers.Tile>} The added OpenLayers.Tile
      */
-    addTile:function(bounds, position) {
+    addTile: function(bounds, position) {
-        return new OpenLayers.Tile.Image(this, position, bounds, null, 
+        return new this.tileClass(this, position, bounds, null,
-                                         this.tileSize, this.tileOptions);
+                                  this.tileSize, this.tileOptions);
     },
     
     /** 

tests/Layer/Grid.html

@@ -21,13 +21,14 @@
 
 
     function test_Layer_Grid_constructor (t) {
-        t.plan( 5 );
+        t.plan( 6 );
                        
         layer = new OpenLayers.Layer.Grid(name, url, params, null);
         t.ok( layer instanceof OpenLayers.Layer.Grid, "returns OpenLayers.Layer.Grid object" );
         t.eq( layer.buffer, 0, "buffer default is 0");
         t.eq( layer.ratio, 1.5, "ratio default is 1.5");
         t.eq( layer.numLoadingTiles, 0, "numLoadingTiles starts at 0");
+        t.eq( layer.tileClass, OpenLayers.Tile.Image, "tileClass default is OpenLayers.Tile.Image");
 
         var obj = {};
         var func = function() {};
@@ -48,6 +49,25 @@
         
     }
 
+    function test_Layer_Grid_tileClass(t) {
+        t.plan(2);
+
+        var myTileClass = OpenLayers.Class(OpenLayers.Tile, {});
+        var map = new OpenLayers.Map('map');
+        layer = new OpenLayers.Layer.WMS(name, url, params, {
+            tileClass: myTileClass
+        });
+        map.addLayer(layer);
+
+        t.eq(layer.tileClass, myTileClass, "tileClass is set");
+        var instance = layer.addTile(new OpenLayers.Bounds(-10, 10, 50, 100),
+                                     new OpenLayers.Pixel(10, 12));
+
+        t.ok(instance instanceof myTileClass, "addTile returns type is correct");
+
+        map.destroy();
+    }
+
     function test_Layer_Grid_clearTiles (t) {
         t.plan(4);