code: public void setPoints(Iterable<Point> points) {
  		if (points==null) throw new NullPointerException();
  		this.points.clear();
  		for (Point p : points) {
  			this.points.add(new Point(p));
  		}
  		repaint();
  	}
docs: Sets the marked pixels.
  @param points an iterable of all the pixels that should be selected
  @throws NullPointerException if {@code points} or any individual point is {@code null}