// same brightness level count for each channel for now

sclass PosterizeBufferedImage is PixelPreservingImageOpResult<BufferedImage> {

  BufferedImage img;

  BufferedImage result;

  IPosterizer posterizer;

  CachedPosterizer cachedPosterizer;

  *(int brightnessLevels, BufferedImage *img) {

    if (brightnessLevels >= 256 || img == null)

      posterizer = new DummyPosterizer;

    posterizer = SinglePixelPosterizer(brightnessLevels);

  }

  *(IPosterizer *posterizer, BufferedImage *img) {}

  run {

    if (img == null) ret;

    if (posterizer cast DummyPosterizer)

      ret with result = img;

    GrabbableIntPixels gp = grabbableIntPixels_fastOrSlow(img);

    int w = img.getWidth(), h = img.getHeight(), n = w*h;

    int[] pixels = gp.data;

    int[] pixels2 = new[n];

    cachePosterizer();

    var cachedPosterizer = this.cachedPosterizer;

    int iOut = 0, iIn = gp.offset;

    for y to h: {

      for x to w: {

        int rgb = pixels[iIn+x];

        pixels2[iOut++] = rgbInt(

          cachedPosterizer.get(rgbRed(rgb)),

          cachedPosterizer.get(rgbGreen(rgb)),

          cachedPosterizer.get(rgbBlue(rgb)));

      }

      iIn += gp.scanlineStride;

    }

    result = bufferedImageWithoutAlpha(w, h, pixels2);

  }

  public BufferedImage pixelPreservingSrcImage() { ret img; }

  BufferedImage get() { if (result == null) run(); ret result; }

  private void cachePosterizer {

    if (cachedPosterizer == null)

      cachedPosterizer = main cachePosterizer(posterizer);

  }

}