interface IImageRegion<Img extends WidthAndHeight> extends INumberOfPixels, IPixelSet {

  // REQUIRED METHODS

  // smallest rectangle that all of the region's pixels are contained in

  public Rect bounds();

  public ItIt<Pt> pixelIterator();

  public bool contains(int x, int y);

  // OPTIONAL METHODS

  // get whole image that the region refers to

  public default Img image() { null; }

  // which object made this

  public default O creator() { null; }

  public default int indexInCreator() { ret 0; }

  // was diagonal walking enabled?

  public default Bool createdWithDiagonals() { null; }

  public default int numberOfPixels aka nPixels() { ret l(pixelIterator()); }

  public default Pt firstPixel() { ret first(pixelIterator()); }

  // gets the region's color (what exactly this means is defined

  // by the creator of this object)

  public default Color color() { null; }

  public default int brightness() { ret -1; }

  public default OnePathWithOrigin outline() {

    ret g22_regionOutline(this);

  }

  default Image2B toImage2B() { ret new RegionToImage2B(this)!; }

  default int[] pixelsAsIntArray() { throw unimplemented(); }

  // CONVENIENCE/ORTHOGONALITY METHODS

  default IPixelSet pixelSet() { this; }

}