!7

// Actually the relationship between the white and the black part
// could be much more general. Why do they have to touch each other?
// Why do they need to have the same aspect ratio? Only the area has
// to be the same.
//
// And even that could be lifted by applying a correction factor
// (area white / area black).
//
// Finally, they can even overlap, then you'd use a factor of
// (non-overlapping white area / non-overlapping black area).
//
// No idea if these would then be called "generalized Haar features" or what
//
// The general unit returned by a Haar match should be pixels*brightness
// (value can be negative too).
//
// Result classification:
//   positive = match
//   0        = non-match (indifferent/not applicable)
//   negative = anti-match (Haar feature should be inverted)

p-subst {
  repeat with sleep 1 {
    currentImage(newBufferedImage(200, 200, Color.gray));
    Rect r = randomRect();
    Pair<Rect> p;
    if (tossCoin()) {
      r.h &= ~1; // make even
      p = splitRectInVerticalHalves(r);
    } else {
      r.w &= ~1; // make even
      p = splitRectInHorizontalHalves(r);
    }
    if (oneInTwoChance()) p = reversePair(p);
    fillRect(p.a, Color.black);
    fillRect(p.b, Color.white);
    quickShowImage();
  }
}

Began life as a copy of #1006918