code: static boolean isClusterCandidate_(double x_1, double y1, double x2,
  			double y2, double sqr_tolerance) {
  		double dx = x_1 - x2;
  		double dy = y1 - y2;
  		return dx * dx + dy * dy <= sqr_tolerance;
  	}
docs: makes sure Simplified shape is more robust to transformations.