asclass ImageSurfaceMouseHandler > MouseAdapter is AutoCloseable {
  ImageSurface is;

  void register(ImageSurface is) {
    this.is = is;
    is.tools.add(this);
    is.addMouseListener(this);
    is.addMouseMotionListener(this);
  }
  
  close {
    if (is == null) ret;
    is.tools.remove(this);
    is.removeMouseListener(this);
    is.removeMouseMotionListener(this);
    is = null;
  }
  
  Pt getPt(MouseEvent e) {
    ret toPt(getPoint(e));
  }
  
  Point getPoint(MouseEvent e) {
    ret new Point((int) (e.getX()/is.getZoomX()), (int) (e.getY()/is.getZoomY()));
  }
  
  ImageSurface getImageSurface() { ret is; }
}