Centroid.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2013 Sandro Santilli <strk@kbt.io>
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: algorithm/Centroid.java r728 (JTS-0.13+)
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/export.h>
#include <geos/geom/Coordinate.h> // for composition
#include <memory> // for std::unique_ptr
 
// Forward declarations
namespace geos {
namespace geom {
class Geometry;
class Polygon;
class CoordinateSequence;
}
}
 
 
namespace geos {
namespace algorithm { // geos::algorithm
 
class GEOS_DLL Centroid {
 
public:
 
    static bool getCentroid(const geom::Geometry& geom, geom::CoordinateXY& cent);
 
    Centroid(const geom::Geometry& geom)
        :
        areasum2(0.0),
        totalLength(0.0),
        ptCount(0)
    {
        add(geom);
    }
 
    bool getCentroid(geom::CoordinateXY& cent) const;
 
private:
 
    std::unique_ptr<geom::CoordinateXY> areaBasePt;
    geom::CoordinateXY triangleCent3;
    geom::CoordinateXY cg3;
    geom::CoordinateXY lineCentSum;
    geom::CoordinateXY ptCentSum;
    double areasum2;
    double totalLength;
    int ptCount;
 
    void add(const geom::Geometry& geom);
 
    void setAreaBasePoint(const geom::CoordinateXY& basePt);
 
    void add(const geom::Polygon& poly);
 
    void addShell(const geom::CoordinateSequence& pts);
 
    void addHole(const geom::CoordinateSequence& pts);
 
    void addTriangle(const geom::CoordinateXY& p0, const geom::CoordinateXY& p1, const geom::CoordinateXY& p2,
                     bool isPositiveArea);
 
    static void centroid3(const geom::CoordinateXY& p1, const geom::CoordinateXY& p2, const geom::CoordinateXY& p3,
                          geom::CoordinateXY& c);
 
    static double area2(const geom::CoordinateXY& p1, const geom::CoordinateXY& p2, const geom::CoordinateXY& p3);
 
    void addLineSegments(const geom::CoordinateSequence& pts);
 
    void addPoint(const geom::CoordinateXY& pt);
};
 
} // namespace geos::algorithm
} // namespace geos