static new ThreadLocal<Double> screenLens_sleep;
static new ThreadLocal<Int> screenLens_w;
static new ThreadLocal<Int> screenLens_h;

static ImageSurface screenLens() {
  final double sleep = optParam(screenLens_sleep, 0.2);
  final int w = optParam(screenLens_w, 300);
  final int h = optParam(screenLens_h, 300);
  ret (ImageSurface) swingAndWait(func {
    final ImageSurface is = alwaysOnTop(showImage(new RGBImage(w, h, Color.white;
    hideConsole(;
    installTimer(is, toMS(sleep), r {
      Rect r = intersectWithScreen(rectAround(new Pt(mouseLocation()), w, h));
      BufferedImage img = shootScreen2(r);
      is.setImage(img);
    });
  });
}