static bool containsColor(BufferedImage img, int color) {
  if (img == null) false;
  color |= 0xFF000000; // alpha
  int w = img.getWidth(), h = img.getHeight();
  for (int x = 0; x < w; x++)
    for (int y = 0; y < h; y++) {
      int rgba = img.getRGB(x, y);
      if (rgba == color) true;
    }
  false;
}