final sclass BWIntegralImage_luminosity extends BWIntegralImage {
  *() {}
  *(File f) { super(f); }
  *(MakesBufferedImage img) { super(img); }
  *(BufferedImage image) { super(image); }
  *(GrabbableIntPixels gp) { super(gp); }
  *(BWImage img) { super(img); }
  
  int packedToBrightness(int packed) {
    ret rgbToLuminosity(packed);
  }
}

Began life as a copy of #1019595