sclass FastRegions_BWImage extends AbstractFastRegions<BWImage> {
  int getColor(int pos) { ret image.getInt(x(pos), y(pos)); }
  
  RGB rgbForRegion(ImageRegion r) {
    ret rgbFromGrayscale(r.brightness());
  }  
  
  *(BWImage img) { super(img); }
  *(BufferedImage img) { this(toBWImage(img)); }
}