static int from332(byte x) {
  int r = iround(((x >> 5) & 7)*255.0/7);
  int g = iround(((x >> 2) & 7)*255.0/7);
  int b = iround((x & 3)*255.0/3);
  ret (r << 16) | (g << 8) | b;
}

static int from332(int r, int g, int b) {
  ret (r << 16) | (g << 8) | b;
}