ConvexHull.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2005-2006 Refractions Research Inc.
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 *
 * 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/ConvexHull.java r407 (JTS-1.12+)
 *
 **********************************************************************/

#pragma once

#include <geos/export.h>
#include <memory>
#include <vector>
#include <cassert>

// FIXME: avoid using Coordinate:: typedefs to avoid full include
#include <geos/algorithm/ConvexHull.h>
#include <geos/geom/Coordinate.h>
#include <geos/geom/CoordinateSequence.h>
#include <geos/geom/Geometry.h>
#include <geos/util/UniqueCoordinateArrayFilter.h>
#include <geos/util/CoordinateArrayFilter.h>

#include "geos/util.h"

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class
#endif

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

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

class GEOS_DLL ConvexHull {
private:

    static constexpr std::size_t TUNING_REDUCE_SIZE = 50;

    const geom::Geometry* inputGeom;
    const geom::GeometryFactory* geomFactory;
    geom::Coordinate::ConstVect inputPts;

    std::unique_ptr<geom::CoordinateSequence> toCoordinateSequence(geom::Coordinate::ConstVect& cv);

    void computeInnerOctolateralPts(
        const geom::Coordinate::ConstVect& src,
        geom::Coordinate::ConstVect& tgt);

    bool computeInnerOctolateralRing(
        const geom::Coordinate::ConstVect& src,
        geom::Coordinate::ConstVect& tgt);

    void reduce(geom::Coordinate::ConstVect& pts);

    void padArray3(geom::Coordinate::ConstVect& pts);

    void preSort(geom::Coordinate::ConstVect& pts);

    int polarCompare(const geom::Coordinate& o,
                     const geom::Coordinate& p,
                     const geom::Coordinate& q);

    void grahamScan(const geom::Coordinate::ConstVect& c,
                    geom::Coordinate::ConstVect& ps);

    std::unique_ptr<geom::Geometry> lineOrPolygon(const geom::Coordinate::ConstVect& vertices);

    void cleanRing(const geom::Coordinate::ConstVect& input,
                   geom::Coordinate::ConstVect& cleaned);

    bool isBetween(
        const geom::Coordinate& c1,
        const geom::Coordinate& c2,
        const geom::Coordinate& c3);

    bool extractUnique(geom::Coordinate::ConstVect& pts, std::size_t maxPts);
    std::unique_ptr<geom::Geometry> createFewPointsResult();



public:

    ConvexHull(const geom::Geometry* newGeometry)
        : inputGeom(newGeometry)
        , geomFactory(newGeometry->getFactory())
    {
      util::ensureNoCurvedComponents(inputGeom);
    };

    ~ConvexHull() {};

    std::unique_ptr<geom::Geometry> getConvexHull();
};

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

#ifdef _MSC_VER
#pragma warning(pop)
#endif