// 0xRRGGBB - result is between 0 and 255*255*3
static int rgbDistanceSquaredInt(int a, int b) {
  ret
    sqrUbyte(absDiff(rgbRed(a), rgbRed(b))) +
    sqrUbyte(absDiff(rgbGreen(a), rgbGreen(b))) +
    sqrUbyte(absDiff(rgbBlue(a), rgbBlue(b)));
}