public void setCalloutAnchor(double x, double y) {
   calloutAnchorIsSet = true;
   calloutAnchorX = (float) x;
   calloutAnchorY = (float) y;
   if (marker != null) {
     marker.setInfoWindowAnchor(calloutAnchorX, calloutAnchorY);
   }
   update();
 }