static void copyImagePart(BufferedImage src, int srcx, int srcy, BufferedImage dest, int destx, int desty, int w, int h) {
  Graphics2D g = dest.createGraphics();
  BufferedImage sub = src.getSubimage(srcx, srcy, w, h);
  g.drawImage(sub, destx, desty, null);
  g.dispose();
}