public void repaint(Rectangle r){
  repaint(0,r.x,r.y,r.width,r.height);
}

public void repaint ( Rectangle r ) { repaint ( 0 , r . x , r . y , r . width , r . height ) ; }
adds the specified region to the dirty region list if the component is showing . the component will be repainted after all of the currently pending events have been dispatched .
