special precautions must be taken in updateBackBufferData

2011-10-19 23:47:25 +02:00
parent 7ffec2e88b
commit 76e8a800da
1 changed files with 6 additions and 2 deletions
@@ -493,7 +493,11 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
        if(this.map) {
            var resolution = this.map.getResolution();
            this.backBufferData.resolution = this.getServerResolution(resolution);
+        }
+        // the top left tile might have been destroyed, so its bounds
+        // property may be null
        var topLeftTile = this.grid[0][0];
+        if(topLeftTile.bounds) {
            this.backBufferData.lonlat = {lon: topLeftTile.bounds.left,
                                          lat: topLeftTile.bounds.top};
        }