// keeps a set of "masks" (remembered shapes) with labels
// simple version without hashes or trees
// A is the user object associated with each mask (aka a "label")
sclass G22SimpleMasksHolder<A> {
  record noeq Mask(Image2B image, A label) {
    Image2B image() { ret image; }
  }

  gettable new L<Mask> masks;
  
  void addRegion(IImageRegion region, A label) {
    masks.add(new Mask(regionToMaskImage(region), label));
    ghost_cache = null;
    certainty_cache = null;
    labels.add(label);
  }

  !include early #1035854 // Masks holder Include
}