Quadrant.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * 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: geomgraph/Quadrant.java rev. 1.8 (JTS-1.10)
 *
 **********************************************************************/
 
 
#ifndef GEOS_GEOMGRAPH_QUADRANT_H
#define GEOS_GEOMGRAPH_QUADRANT_H
 
#include <geos/export.h>
#include <string>
 
#include <geos/inline.h>
 
// Forward declarations
namespace geos {
        namespace geom {
                class Coordinate;
        }
}
 
namespace geos {
namespace geomgraph { // geos.geomgraph

class GEOS_DLL Quadrant {
 
public:
 
        static const int NE = 0;
        static const int NW = 1;
        static const int SW = 2;
        static const int SE = 3;

        static int quadrant(double dx, double dy);

        static int quadrant(const geom::Coordinate& p0,
                            const geom::Coordinate& p1);

        static bool isOpposite(int quad1, int quad2);
 
        /* 
         * Returns the right-hand quadrant of the halfplane defined by
         * the two quadrants,
         * or -1 if the quadrants are opposite, or the quadrant if they
         * are identical.
         */
        static int commonHalfPlane(int quad1, int quad2);

        static bool isInHalfPlane(int quad, int halfPlane);

        static bool isNorthern(int quad);
};
 
 
} // namespace geos.geomgraph
} // namespace geos
 
#endif // ifndef GEOS_GEOMGRAPH_QUADRANT_H