static void drawBox(BufferedImage image, Rect r, Color color, double opaqueness) {
  if (r == null) ret;
  Graphics2D g = image.createGraphics();
  g.setColor(colorWithAlpha(color, opaqueness));
  g.drawRect(r.x-1, r.y-1, r.w+2, r.h+2);
  g.dispose();
}