code: function() {
          var bounds = this.map.getExtent();
          if (this.rotation) {
              var origin = this.getOrigin();
              var rotationOrigin = new OpenLayers.Geometry.Point(origin.lon, origin.lat);
              var rect = bounds.toGeometry();
              rect.rotate(-this.rotation, rotationOrigin);
              bounds = rect.getBounds();
          }
          return bounds;
      }
docs: Method: getViewBounds
  Gets the (potentially rotated) view bounds for grid calculations.
  
  Returns:
  {<OpenLayers.Bounds>}