code: function () {
          // -- todo make the viewInfo properties  flat objects.
          var size = this._map.getSize();
          var bounds = this._map.getBounds();
          var zoom = this._map.getZoom();
  
          var center = this.LatLonToMercator(this._map.getCenter());
          var corner = this.LatLonToMercator(this._map.containerPointToLatLng(this._map.getSize()));
  
          var del = this._delegate || this;
          del.onDrawLayer && del.onDrawLayer({
              layer: this,
              canvas: this._canvas,
              bounds: bounds,
              size: size,
              zoom: zoom,
              center: center,
              corner: corner
          });
          this._frame = null;
      }
docs: ------------------------------------------------------------------------------