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;
  }
}