private List<Integer> getTrianglesWithin(float x, float y, float r) {
		TriangleComponent[] tc = view.getTriangles();
		if (tc == null || tc.length == 0)
			return null;
		List<Integer> list = new ArrayList<Integer>();
		Rectangle2D.Float rect = new Rectangle2D.Float(x - r, y - r, 2 * r, 2 * r);
		for (int i = 0; i < tc.length; i++) {
			if (tc[i].getShape().intersects(rect)) {
				list.add(i);
			}
		}
		return list;
	}