Class PointPairDistance

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12
13	package org.locationtech.jts.algorithm.distance;
14
15	import org.locationtech.jts.geom.Coordinate;
16	import org.locationtech.jts.io.WKTWriter;
17
18	/**
19	* Contains a pair of points and the distance between them.
20	* Provides methods to update with a new point pair with
21	* either maximum or minimum distance.
22	*/
23	public class PointPairDistance {
24
25	private Coordinate[] pt = { new Coordinate(), new Coordinate() };
26	private double distance = Double.NaN;
27	private boolean isNull = true;
28
29	public PointPairDistance()
30	{
31	}
32
33	public void initialize() { isNull = true; }
34
35	public void initialize(Coordinate p0, Coordinate p1)
36	{
37	pt[0].setCoordinate(p0);
38	pt[1].setCoordinate(p1);
39	distance = p0.distance(p1);
40	isNull = false;
41	}
42
43	/**
44	* Initializes the points, avoiding recomputing the distance.
45	* @param p0
46	* @param p1
47	* @param distance the distance between p0 and p1
48	*/
49	private void initialize(Coordinate p0, Coordinate p1, double distance)
50	{
51	pt[0].setCoordinate(p0);
52	pt[1].setCoordinate(p1);
53	this.distance = distance;
54	isNull = false;
55	}
56
57	public double getDistance() { return distance; }
58
59	public Coordinate[] getCoordinates() { return pt; }
60
61	public Coordinate getCoordinate(int i) { return pt[i]; }
62
63	public void setMaximum(PointPairDistance ptDist)
64	{
65	setMaximum(ptDist.pt[0], ptDist.pt[1]);
66	}
67
68	public void setMaximum(Coordinate p0, Coordinate p1)
69	{
70	if (isNull) {
71	initialize(p0, p1);
72	return;
73	}
74	double dist = p0.distance(p1);
75	if (dist > distance)
76	initialize(p0, p1, dist);
77	}
78
79	public void setMinimum(PointPairDistance ptDist)
80	{
81	setMinimum(ptDist.pt[0], ptDist.pt[1]);
82	}
83
84	public void setMinimum(Coordinate p0, Coordinate p1)
85	{
86	if (isNull) {
87	initialize(p0, p1);
88	return;
89	}
90	double dist = p0.distance(p1);
91	if (dist < distance)
92	initialize(p0, p1, dist);
93	}
94
95	public String toString()
96	{
97	return WKTWriter.toLineString(pt[0], pt[1]);
98	}
99	}
100