sclass Hi15Image extends WAndHImpl is MakesBufferedImage {
  short[] pixels;
  
  *() {} // for persistence
  *(int *w, int *h, short[] *pixels) {}
  
  // TODO: optimize!
  *(BufferedImage img) { this(RGBImage(img)); }
  *(RGBImage img) {
    w = img.getWidth();
    h = img.getHeight();
    pixels = new short[w*h];
    for y to h: for x to w:
      pixels[y*w+x] = rgbIntToHi15(img.getInt(x, y));
  }
  
  *(MakesBufferedImage img) { this(toBufferedImage(img)); }
  
  RGBImage toRGB() {
    RGBImage img = new RGBImage(w, h);
    int i = 0, w = this.w, h = this.h;
    for y to h: for x to w:
      img.setPixel(x, y, hi15ToRGBInt(pixels[i++]));
    ret img;
  }
  
  public BufferedImage getBufferedImage() {
    ret toRGB().getBufferedImage();
  }
  
  // 0 to 32767
  short getHi15Pixel aka getHi15Color(int x, int y) {
    ret pixels[y*w+x];
  }
  
  // idx = index in pixel array
  public short getHi15Pixel_noRangeCheck(int idx) {
    ret pixels[idx];
  }
  
  static int perChannelBitCountMask(int bitCount) {
    int mask = ((~0x1F) >> bitCount) & 0x1F;
    int mask2 = (mask << 10) | (mask << 5) | mask;
    ret mask2;
  }
  
  void reducePerChannelBitCount(int bitCount) {
    if (bitCount >= 5) ret;
    int mask = perChannelBitCountMask(bitCount);
    short[] pixels = this.pixels;
    for (int i = 0; i < pixels.length; i++)
      pixels[i] = (short) (pixels[i] & mask);
  }
  
  void reduceColorCount(int numColors) {
    assertPowerOfTwo(numColors);
    int bits = dualLog(numColors);
    assertDivisibleBy(3, bits);
    int bitsPerChannel = bits/3;
    reducePerChannelBitCount(bitsPerChannel);
  }
}

Began life as a copy of #1005378