protected virtual void OnPolygonDrawn(DrawnPolygonEventArgs e)
 {
     if (PolygonDrawn != null)
     {
         PolygonDrawn(this, e);
     }
 }
 protected virtual void OnRectangleDrawn(DrawnPolygonEventArgs e)
 {
     if (RectangleDrawn != null)
     {
         RectangleDrawn(this, e);
     }
 }