Centroid.h

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/**********************************************************************
 *
 * 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+)
 *
 **********************************************************************/

#ifndef GEOS_ALGORITHM_CENTROID_H
#define GEOS_ALGORITHM_CENTROID_H

#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::Coordinate& cent);

    Centroid(const geom::Geometry& geom)
        :
        areasum2(0.0),
        totalLength(0.0),
        ptCount(0)
    {
        add(geom);
    }

    bool getCentroid(geom::Coordinate& cent) const;

private:

    std::unique_ptr<geom::Coordinate> areaBasePt;
    geom::Coordinate triangleCent3;
    geom::Coordinate cg3;
    geom::Coordinate lineCentSum;
    geom::Coordinate ptCentSum;
    double areasum2;
    double totalLength;
    int ptCount;

    void add(const geom::Geometry& geom);

    void setAreaBasePoint(const geom::Coordinate& basePt);

    void add(const geom::Polygon& poly);

    void addShell(const geom::CoordinateSequence& pts);

    void addHole(const geom::CoordinateSequence& pts);

    void addTriangle(const geom::Coordinate& p0, const geom::Coordinate& p1, const geom::Coordinate& p2,
                     bool isPositiveArea);

    static void centroid3(const geom::Coordinate& p1, const geom::Coordinate& p2, const geom::Coordinate& p3,
                          geom::Coordinate& c);

    static double area2(const geom::Coordinate& p1, const geom::Coordinate& p2, const geom::Coordinate& p3);

    void addLineSegments(const geom::CoordinateSequence& pts);

    void addPoint(const geom::Coordinate& pt);
};

} // namespace geos::algorithm
} // namespace geos

#endif // GEOS_ALGORITHM_CENTROID_H