/** Clean used resources. */
 public void clean() {
   if (_clippingPath != null) {
     _gc.setClipping((Rectangle) null);
     _clippingPath.dispose();
     _clippingPath = null;
     _clippingArea = null;
   }
   if (_color != null) {
     _color.dispose();
     _color = null;
   }
   if (_transform != null) {
     _gc.setTransform(null);
     _transform.dispose();
   }
 }