GEOS  3.13.0dev
Centroid.h
1 /**********************************************************************
2  *
3  * GEOS - Geometry Engine Open Source
4  * http://geos.osgeo.org
5  *
6  * Copyright (C) 2013 Sandro Santilli <strk@kbt.io>
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/Centroid.java r728 (JTS-0.13+)
16  *
17  **********************************************************************/
18 
19 #pragma once
20 
21 #include <geos/export.h>
22 #include <geos/geom/Coordinate.h> // for composition
23 #include <memory> // for std::unique_ptr
24 
25 // Forward declarations
26 namespace geos {
27 namespace geom {
28 class Geometry;
29 class Polygon;
30 class CoordinateSequence;
31 }
32 }
33 
34 
35 namespace geos {
36 namespace algorithm { // geos::algorithm
37 
60 class GEOS_DLL Centroid {
61 
62 public:
63 
73  static bool getCentroid(const geom::Geometry& geom, geom::CoordinateXY& cent);
74 
78  Centroid(const geom::Geometry& geom)
79  :
80  areasum2(0.0),
81  totalLength(0.0),
82  ptCount(0)
83  {
84  add(geom);
85  }
86 
95  bool getCentroid(geom::CoordinateXY& cent) const;
96 
97 private:
98 
99  std::unique_ptr<geom::CoordinateXY> areaBasePt;
100  geom::CoordinateXY triangleCent3;
101  geom::CoordinateXY cg3;
102  geom::CoordinateXY lineCentSum;
103  geom::CoordinateXY ptCentSum;
104  double areasum2;
105  double totalLength;
106  int ptCount;
107 
113  void add(const geom::Geometry& geom);
114 
115  void setAreaBasePoint(const geom::CoordinateXY& basePt);
116 
117  void add(const geom::Polygon& poly);
118 
119  void addShell(const geom::CoordinateSequence& pts);
120 
121  void addHole(const geom::CoordinateSequence& pts);
122 
123  void addTriangle(const geom::CoordinateXY& p0, const geom::CoordinateXY& p1, const geom::CoordinateXY& p2,
124  bool isPositiveArea);
125 
131  static void centroid3(const geom::CoordinateXY& p1, const geom::CoordinateXY& p2, const geom::CoordinateXY& p3,
132  geom::CoordinateXY& c);
133 
138  static double area2(const geom::CoordinateXY& p1, const geom::CoordinateXY& p2, const geom::CoordinateXY& p3);
139 
146  void addLineSegments(const geom::CoordinateSequence& pts);
147 
152  void addPoint(const geom::CoordinateXY& pt);
153 };
154 
155 } // namespace geos::algorithm
156 } // namespace geos
157 
Computes the centroid of a Geometry of any dimension.
Definition: Centroid.h:60
Centroid(const geom::Geometry &geom)
Creates a new instance for computing the centroid of a geometry.
Definition: Centroid.h:78
static bool getCentroid(const geom::Geometry &geom, geom::CoordinateXY &cent)
Computes the centroid point of a geometry.
bool getCentroid(geom::CoordinateXY &cent) const
Gets the computed centroid.
The internal representation of a list of coordinates inside a Geometry.
Definition: CoordinateSequence.h:56
Basic implementation of Geometry, constructed and destructed by GeometryFactory.
Definition: Geometry.h:186
Represents a linear polygon, which may include holes.
Definition: Polygon.h:60
Basic namespace for all GEOS functionalities.
Definition: Angle.h:25