@Override
 public void mouseDragged(MouseEvent e) {
   DrawPad drawPad = (DrawPad) parent;
   if (drawPad.getSelectedLayer().isHidden()) {
     return;
   }
   if (isLeftButtonPressed) {
     if (drawPad.isRubberMode()) {
       drawPad.getSelectedLayer().erase(e.getPoint());
     } else {
       drawPad.getSelectedLayer().drawLine(e.getPoint());
     }
     parent.repaint();
   }
 }