grayScale method

Implementation

Color grayScale() {
  ColorFloatStrip stripped = strip();
  int val = ((0.299 * stripped.red +
              0.587 * stripped.green +
              0.114 * stripped.blue) *
          255)
      .toInt()
      .clamp(0, 255);
  return Color.fromARGB(
      (stripped.alpha * 255).toInt(), val, val, val);
}