New events: loaderror for Tile, tileerror for Layer.Grid.

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/Tile.js

@@ -40,6 +40,8 @@ OpenLayers.Tile = OpenLayers.Class({
      *     to call <draw>(true) to actually draw the tile.
      * loadstart - Triggered when tile loading starts.
      * loadend - Triggered when tile loading ends.
+     * loaderror - Triggered before the loadend event (i.e. when the tile is
+     *     still hidden) if the tile could not be loaded.
      * reload - Triggered when an already loading tile is reloaded.
      * unload - Triggered before a tile is unloaded.
      */

lib/OpenLayers/Tile/Image.js

@@ -425,6 +425,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
                 this.setImgSrc(this.layer.getURL(this.bounds));
             } else {
                 OpenLayers.Element.addClass(img, "olImageLoadError");
+                this.events.triggerEvent("loaderror");
                 this.onImageLoad();
             }
         }