code: function (layer) {
              var bounds = layer instanceof me.TMXLayer ? me.pool.pull("me.Rect", 0, 0, 0, 0) : this.bounds;
              bounds.setShape(
                  0, 0,
                  this.cols * this.tilewidth,
                  this.rows * this.tileheight
              );
              return bounds;
          }
docs: return the bounding rect for this map renderer
  @name me.TMXRenderer#getBounds
  @public
  @function
  @param {me.TMXLayer} [layer] calculate the bounding rect for a specific layer (will return a new bounds object)
  @return {me.Rect}