fix for #785 - fix up gutter logic a little bit. on a path to getting all gutter info in one place

git-svn-id: http://svn.openlayers.org/trunk/openlayers@3555 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -381,6 +381,14 @@ OpenLayers.Layer.prototype = {
             this.setTileSize();
         }
     },
+    
+    /**  
+     * @returns The size that the image should be, taking into account gutters 
+     * @tile OpenLayers.Size 
+     */ 
+    getImageSize: function() { 
+        return (this.imageSize || this.tileSize); 
+    },    
   
     /**
      * APIMethod: setTileSize
@@ -405,11 +413,6 @@ OpenLayers.Layer.prototype = {
             this.imageOffset = new OpenLayers.Pixel(-this.gutter, -this.gutter); 
             this.imageSize = new OpenLayers.Size(tileSize.w + (2 * this.gutter), 
                                                  tileSize.h + (2 * this.gutter)); 
-        } else {
-            // layers without gutters may have null tile size - as long
-            // as they don't rely on Tile.Image
-            this.imageSize = tileSize;
-            this.imageOffset = new OpenLayers.Pixel(0, 0);
         }
     },