GEOS 3.9.1
CentralEndpointIntersector.h
1/**********************************************************************
2 *
3 * GEOS - Geometry Engine Open Source
4 * http://geos.osgeo.org
5 *
6 * Copyright (C) 2006 Refractions Research Inc.
7 *
8 * This is free software; you can redistribute and/or modify it under
9 * the terms of the GNU Lesser General Public Licence as published
10 * by the Free Software Foundation.
11 * See the COPYING file for more information.
12 *
13 **********************************************************************
14 *
15 * Last port: algorithm/CentralEndpointIntersector.java rev. 1.1
16 *
17 **********************************************************************/
18
19#ifndef GEOS_ALGORITHM_CENTRALENDPOINTINTERSECTOR_H
20#define GEOS_ALGORITHM_CENTRALENDPOINTINTERSECTOR_H
21
22#include <geos/export.h>
23#include <geos/geom/Coordinate.h>
24
25#include <string>
26#include <limits>
27
28#ifdef _MSC_VER
29#pragma warning(push)
30#pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class
31#endif
32
33// Forward declarations
34namespace geos {
35namespace geom {
36//class PrecisionModel;
37}
38}
39
40namespace geos {
41namespace algorithm { // geos::algorithm
42
63
64public:
65
66 static const geom::Coordinate&
67 getIntersection(const geom::Coordinate& p00,
68 const geom::Coordinate& p01, const geom::Coordinate& p10,
69 const geom::Coordinate& p11)
70 {
71 CentralEndpointIntersector intor(p00, p01, p10, p11);
72 return intor.getIntersection();
73 }
74
76 const geom::Coordinate& p01,
77 const geom::Coordinate& p10,
78 const geom::Coordinate& p11)
79 :
80 _pts(4)
81 {
82 _pts[0] = p00;
83 _pts[1] = p01;
84 _pts[2] = p10;
85 _pts[3] = p11;
86 compute();
87 }
88
89 const geom::Coordinate&
90 getIntersection() const
91 {
92 return _intPt;
93 }
94
95
96private:
97
98 // This is likely overkill.. we'll be allocating heap
99 // memory at every call !
100 std::vector<geom::Coordinate> _pts;
101
102 geom::Coordinate _intPt;
103
104 void
105 compute()
106 {
107 geom::Coordinate centroid = average(_pts);
108 _intPt = findNearestPoint(centroid, _pts);
109 }
110
111 static geom::Coordinate
112 average(
113 const std::vector<geom::Coordinate>& pts)
114 {
115 geom::Coordinate avg(0, 0);
116 size_t n = pts.size();
117 if(! n) {
118 return avg;
119 }
120 for(std::size_t i = 0; i < n; ++i) {
121 avg.x += pts[i].x;
122 avg.y += pts[i].y;
123 }
124 avg.x /= n;
125 avg.y /= n;
126 return avg;
127 }
128
140 findNearestPoint(const geom::Coordinate& p,
141 const std::vector<geom::Coordinate>& pts) const
142 {
143 double minDistSq = std::numeric_limits<double>::max();
144 geom::Coordinate result = geom::Coordinate::getNull();
145 for(std::size_t i = 0, n = pts.size(); i < n; ++i) {
146 double distSq = p.distanceSquared(pts[i]);
147 if(distSq < minDistSq) {
148 minDistSq = distSq;
149 result = pts[i];
150 }
151 }
152 return result;
153 }
154};
155
156} // namespace geos::algorithm
157} // namespace geos
158
159#ifdef _MSC_VER
160#pragma warning(pop)
161#endif
162
163#endif // GEOS_ALGORITHM_CENTRALENDPOINTINTERSECTOR_H
Computes an approximate intersection of two line segments by taking the most central of the endpoints...
Definition: CentralEndpointIntersector.h:62
Coordinate is the lightweight class used to store coordinates.
Definition: Coordinate.h:60
double y
y-coordinate
Definition: Coordinate.h:83
double x
x-coordinate
Definition: Coordinate.h:80
Basic namespace for all GEOS functionalities.
Definition: IndexedNestedRingTester.h:26