// same brightness level count for each channel for now

sclass PosterizeBufferedImageToHi15 {

  BufferedImage img;

  Hi15Image result;

  IPosterizer posterizer;

  *(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 = new Hi15Image(img);

    GrabbableRGBBytePixels gp = grabbableRGBBytePixels(img);

    if (gp != null)

      ret with run(gp);

    GrabbableIntPixels gp2 = grabbableIntPixels_fastOrSlow(img);

    run(gp2);

  }

  void run(GrabbableIntPixels gp) {

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

    int[] pixels = gp.data;

    short[] pixels2 = new[n];

    byte[] cache = cachePosterizer();

    int extraStride = gp.scanlineStride-w;

    int iOut = 0, iIn = gp.offset;

    for y to h: {

      for x to w: {

        int rgb = pixels[iIn++];

        pixels2[iOut++] = (short)

          ((cache[(rgb >> 16) & 0xFF] << 10) |

          (cache[(rgb >> 8) & 0xFF] << 5) |

          cache[rgb & 0xFF]);

      }

      iIn += extraStride;

    }

    result = new Hi15Image(w, h, pixels2);

  }

  void run(GrabbableRGBBytePixels gp) {

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

    byte[] pixels = gp.data;

    short[] pixels2 = new[n];

    byte[] cache = cachePosterizer();

    int extraStride = gp.scanlineStride-w*3;

    int iOut = 0, iIn = gp.offset;

    for y to h: {

      for x to w: {

        int r = pixels[iIn++] & 0xFF;

        int g = pixels[iIn++] & 0xFF;

        int b = pixels[iIn++] & 0xFF;

        pixels2[iOut++] = (short)

          ((cache[r] << 10) |

          (cache[g] << 5) |

          cache[b]);

      }

      iIn += extraStride;

    }

    result = new Hi15Image(w, h, pixels2);

  }

  public BufferedImage pixelPreservingSrcImage() { ret img; }

  Hi15Image get() { if (result == null) run(); ret result; }

  byte[] cachePosterizer() {

    byte[] cache = new[256];

    for i to 256:

      cache[i] = (byte) (posterizer.get(i) >> 3);

    ret cache;

  }

}