Merge branch 'master' of github.com:openlayers/openlayers into utfgrid

lib/OpenLayers/Layer/ArcGISCache.js

@@ -452,7 +452,9 @@ OpenLayers.Layer.ArcGISCache = OpenLayers.Class(OpenLayers.Layer.XYZ, {
         // Write the values into our formatted url
         url = OpenLayers.String.format(url, {'x': x, 'y': y, 'z': z});
 
-        return url;
+        return OpenLayers.Util.urlAppend(
+            url, OpenLayers.Util.getParameterString(this.params)
+        );
     },
 
     /**

lib/OpenLayers/Layer/Grid.js

@@ -202,6 +202,10 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
      *     track of the loading progress. Listeners are called with an object
      *     with a tile property as first argument, making the loded tile
      *     available to the listener.
+     * tileerror - Triggered before the tileloaded event (i.e. when the tile is
+     *     still hidden) if a tile failed to load. Listeners receive an object
+     *     as first argument, which has a tile property that references the
+     *     tile that could not be loaded.
      */
 
     /**
@@ -969,7 +973,6 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
             }
             this.numLoadingTiles++;
         };
-        tile.events.register("loadstart", this, tile.onLoadStart);
       
         tile.onLoadEnd = function() {
             this.numLoadingTiles--;
@@ -987,8 +990,18 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                 }
             }
         };
-        tile.events.register("loadend", this, tile.onLoadEnd);
-        tile.events.register("unload", this, tile.onLoadEnd);
+        
+        tile.onLoadError = function() {
+            this.events.triggerEvent("tileerror", {tile: tile});
+        };
+        
+        tile.events.on({
+            "loadstart": tile.onLoadStart,
+            "loadend": tile.onLoadEnd,
+            "unload": tile.onLoadEnd,
+            "loaderror": tile.onLoadError,
+            scope: this
+        });
     },
 
     /** 
@@ -1005,6 +1018,7 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
             "loadstart": tile.onLoadStart,
             "loadend": tile.onLoadEnd,
             "unload": tile.onLoadEnd,
+            "loaderror": tile.onLoadError,
             scope: this
         });
     },

lib/OpenLayers/Layer/HTTPRequest.js

@@ -60,7 +60,9 @@ OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, {
     initialize: function(name, url, params, options) {
         OpenLayers.Layer.prototype.initialize.apply(this, [name, options]);
         this.url = url;
-        this.params = OpenLayers.Util.extend( {}, params);
+        if (!this.params) {
+            this.params = OpenLayers.Util.extend({}, params);
+        }
     },
 
     /**

lib/OpenLayers/Layer/OSM.js

@@ -34,7 +34,7 @@ OpenLayers.Layer.OSM = OpenLayers.Class(OpenLayers.Layer.XYZ, {
     /**
      * APIProperty: url
      * {String} The tileset URL scheme. Defaults to
-     * : http://tile.openstreetmap.org/${z}/${x}/${y}.png
+     * : http://[a|b|c].tile.openstreetmap.org/${z}/${x}/${y}.png
      * (the official OSM tileset) if the second argument to the constructor
      * is null or undefined. To use another tileset you can have something
      * like this:
@@ -43,7 +43,11 @@ OpenLayers.Layer.OSM = OpenLayers.Class(OpenLayers.Layer.XYZ, {
      *       "http://tah.openstreetmap.org/Tiles/tile/${z}/${x}/${y}.png"); 
      * (end)
      */
-    url: 'http://tile.openstreetmap.org/${z}/${x}/${y}.png',
+    url: [
+        'http://a.tile.openstreetmap.org/${z}/${x}/${y}.png',
+        'http://b.tile.openstreetmap.org/${z}/${x}/${y}.png',
+        'http://c.tile.openstreetmap.org/${z}/${x}/${y}.png'
+    ],
 
     /**
      * Property: attribution