// Abstract base class for tiling an image (G22Tiling)

abstract srecord noeq G22AbstractTiler<Img extends WidthAndHeight>(Img image) is Runnable {
  int w, h, runner;
  gettable int size; // =w*h
  
  // iterator that provides points to be looked at
  // (e.g. a WeightlessShuffledIterator)
  IndexIterator pointIterator;
  
  new IntBuffer stack; // locations to be looked at as y*w+x

  G22Tiling<Img> tiling; // the tiling we are making
  
  bool verbose;
  
  // The one method subclasses need to override
  abstract int getColor(int pos);
  
  // calculations for positions (pixel index)
  int x(int pos) { ret pos % w; }
  int y(int pos) { ret pos / w; }
  int pos(int x, int y) { ret y*w+x; }
  Pt pt(int pos) { ret Pt(x(pos), y(pos)); }
  bool validPos(int x, int y) { ret x >= 0 && y >= 0 && x < w && y < h; }
  
  run {
    w = image.getWidth(); h = image.getHeight();
    size = w*h;
    tiling = new G22Tiling(image);
  }
  
  G22Tiling<Img> get() {
    if (tiling == null) run();
    ret tiling;
  }
}