// undefined color, seems to be all black in practice
static BufferedImage newGrayBufferedImage(int w, int h) {
  ret new BufferedImage(w, h, BufferedImage.TYPE_BYTE_GRAY);
}

static BufferedImage newGrayBufferedImage(int w, int h, byte[] pixels) {
  ret byteArrayToGrayBufferedImage(pixels, w, h);
}