code: void transformWithoutShift(Point2D[] pointsIn, int from, int count,
  			Point2D[] pointsOut) {
  		for (int i = from, n = from + count; i < n; i++) {
  			Point2D p = pointsIn[i];
  			double new_x = xx * p.x + xy * p.y;
  			double new_y = yx * p.x + yy * p.y;
  			pointsOut[i].setCoords(new_x, new_y);
  		}
  	}
docs: be zeroed.