Class PreparedPolygon

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	package org.locationtech.jts.geom.prep;
13
14
15	import org.locationtech.jts.algorithm.locate.IndexedPointInAreaLocator;
16	import org.locationtech.jts.algorithm.locate.PointOnGeometryLocator;
17	import org.locationtech.jts.geom.Geometry;
18	import org.locationtech.jts.geom.MultiPolygon;
19	import org.locationtech.jts.geom.Polygon;
20	import org.locationtech.jts.geom.Polygonal;
21	import org.locationtech.jts.noding.FastSegmentSetIntersectionFinder;
22	import org.locationtech.jts.noding.SegmentStringUtil;
23	import org.locationtech.jts.operation.predicate.RectangleContains;
24	import org.locationtech.jts.operation.predicate.RectangleIntersects;
25
26	/**
27	* A prepared version for {@link Polygonal} geometries.
28	* This class supports both {@link Polygon}s and {@link MultiPolygon}s.
29	* <p>
30	* This class does <b>not</b> support MultiPolygons which are non-valid
31	* (e.g. with overlapping elements).
32	* <p>
33	* Instances of this class are thread-safe and immutable.
34	*
35	* @author mbdavis
36	*
37	*/
38	public class PreparedPolygon
39	extends BasicPreparedGeometry
40	{
41	private final boolean isRectangle;
42	// create these lazily, since they are expensive
43	private FastSegmentSetIntersectionFinder segIntFinder = null;
44	private PointOnGeometryLocator pia = null;
45
46	public PreparedPolygon(Polygonal poly) {
47	super((Geometry) poly);
48	isRectangle = getGeometry().isRectangle();
49	}
50
51	/**
52	* Gets the indexed intersection finder for this geometry.
53	*
54	* @return the intersection finder
55	*/
56	public synchronized FastSegmentSetIntersectionFinder getIntersectionFinder()
57	{
58	/**
59	* MD - Another option would be to use a simple scan for
60	* segment testing for small geometries.
61	* However, testing indicates that there is no particular advantage
62	* to this approach.
63	*/
64	if (segIntFinder == null)
65	segIntFinder = new FastSegmentSetIntersectionFinder(SegmentStringUtil.extractSegmentStrings(getGeometry()));
66	return segIntFinder;
67	}
68
69	public synchronized PointOnGeometryLocator getPointLocator()
70	{
71	if (pia == null)
72	pia = new IndexedPointInAreaLocator(getGeometry());
73
74	return pia;
75	}
76
77	public boolean intersects(Geometry g)
78	{
79	// envelope test
80	if (! envelopesIntersect(g)) return false;
81
82	// optimization for rectangles
83	if (isRectangle) {
84	return RectangleIntersects.intersects((Polygon) getGeometry(), g);
85	}
86
87	return PreparedPolygonIntersects.intersects(this, g);
88	}
89
90	public boolean contains(Geometry g)
91	{
92	// short-circuit test
93	if (! envelopeCovers(g))
94	return false;
95
96	// optimization for rectangles
97	if (isRectangle) {
98	return RectangleContains.contains((Polygon) getGeometry(), g);
99	}
100
101	return PreparedPolygonContains.contains(this, g);
102	}
103
104	public boolean containsProperly(Geometry g)
105	{
106	// short-circuit test
107	if (! envelopeCovers(g))
108	return false;
109	return PreparedPolygonContainsProperly.containsProperly(this, g);
110	}
111
112	public boolean covers(Geometry g)
113	{
114	// short-circuit test
115	if (! envelopeCovers(g))
116	return false;
117	// optimization for rectangle arguments
118	if (isRectangle) {
119	return true;
120	}
121	return PreparedPolygonCovers.covers(this, g);
122	}
123	}
124