MinimumBoundingCircle.h

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/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2019 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * 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/MinimumBoundingCircle.java 2019-01-23
 *
 **********************************************************************/

#ifndef GEOS_ALGORITHM_MINIMUMBOUNDINGCIRCLE_H
#define GEOS_ALGORITHM_MINIMUMBOUNDINGCIRCLE_H

#include <geos/export.h>
#include <geos/geom/Coordinate.h>
#include <geos/geom/CoordinateSequence.h>
#include <geos/geom/Geometry.h>
#include <geos/geom/Point.h>
#include <geos/geom/Triangle.h>

#include <vector>

// Forward declarations
// namespace geos {
//      namespace geom {
//              class GeometryCollection;
//      }
// }


namespace geos {
namespace algorithm { // geos::algorithm

class GEOS_DLL MinimumBoundingCircle {

private:

    // member variables
    const geom::Geometry* input;
    std::vector<geom::Coordinate> extremalPts;
    geom::Coordinate centre;
    double radius;

    void computeCentre();
    void compute();
    void computeCirclePoints();
    geom::Coordinate lowestPoint(std::vector<geom::Coordinate>& pts);
    geom::Coordinate pointWitMinAngleWithX(std::vector<geom::Coordinate>& pts, geom::Coordinate& P);
    geom::Coordinate pointWithMinAngleWithSegment(std::vector<geom::Coordinate>& pts,
            geom::Coordinate& P, geom::Coordinate& Q);
    std::vector<geom::Coordinate> farthestPoints(std::vector<geom::Coordinate>& pts);


public:

    MinimumBoundingCircle(const geom::Geometry* geom):
        input(nullptr),
        radius(0.0)
    {
        input = geom;
        centre.setNull();
    }

    ~MinimumBoundingCircle() {};

    std::unique_ptr<geom::Geometry> getCircle();

    std::unique_ptr<geom::Geometry> getMaximumDiameter();

    std::unique_ptr<geom::Geometry> getDiameter();

    std::vector<geom::Coordinate> getExtremalPoints();

    geom::Coordinate getCentre();

    double getRadius();

};

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

#endif // GEOS_ALGORITHM_MINIMUMBOUNDINGCIRCLE_H