docs: private void addFirstSegment(int x, int y) {
  		Point2D_I32 p = queuePoints.grow();
  		p.set(x,y);
  		EdgeSegment s = new EdgeSegment();
  		s.points.add(p);
  		s.index = 0;
  		s.parent = s.parentPixel = -1;
  		e.segments.add(s);
  		open.add(s);
  	}