CGAlgorithmsDD.h

Go to the documentation of this file.

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2014 Mateusz Loskot <mateusz@loskot.net>
 *
 * 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/CGAlgorithmsDD.java r789 (JTS-1.14)
 *
 **********************************************************************/

#ifndef GEOS_ALGORITHM_CGALGORITHMDD_H
#define GEOS_ALGORITHM_CGALGORITHMDD_H
#include <geos/export.h>
#include <geos/math/DD.h>

// Forward declarations
namespace geos {
namespace geom {
class Coordinate;
class CoordinateSequence;
}
}

using namespace geos::math;

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

class GEOS_DLL CGAlgorithmsDD {

public:

    enum {
        CLOCKWISE = -1,
        COLLINEAR = 0,
        COUNTERCLOCKWISE = 1
    };

    enum {
        RIGHT = -1,
        LEFT = 1,
        STRAIGHT = 0,
        FAILURE = 2
    };

    static int orientationIndex(const geom::Coordinate& p1,
                                const geom::Coordinate& p2,
                                const geom::Coordinate& q);


    static int orientationIndex(double p1x, double p1y,
                                double p2x, double p2y,
                                double qx,  double qy);

    static int orientationIndexFilter(double pax, double pay,
                                      double pbx, double pby,
                                      double pcx, double pcy);


    static int
    orientation(double x)
    {
        if(x < 0) {
            return CGAlgorithmsDD::RIGHT;
        }
        if(x > 0) {
            return CGAlgorithmsDD::LEFT;
        }
        return CGAlgorithmsDD::STRAIGHT;
    }

    static geom::Coordinate intersection(const geom::Coordinate& p1, const geom::Coordinate& p2,
                             const geom::Coordinate& q1, const geom::Coordinate& q2);

    static int signOfDet2x2(double dx1, double dy1, double dx2, double dy2);

    static DD detDD(double x1, double y1, double x2, double y2);
    static DD detDD(const DD& x1, const DD& y1, const DD& x2, const DD& y2);

    static geom::Coordinate circumcentreDD(const geom::Coordinate& a, const geom::Coordinate& b, const geom::Coordinate& c);

protected:

    static int signOfDet2x2(const DD& x1, const DD& y1, const DD& x2, const DD& y2);

};

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

#endif // GEOS_ALGORITHM_CGALGORITHM_H