CentroidArea.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: algorithm/CentroidArea.java r612
 *
 **********************************************************************/
 
#ifndef GEOS_ALGORITHM_CENTROIDAREA_H
#define GEOS_ALGORITHM_CENTROIDAREA_H
 
 
#include <geos/export.h>
#include <geos/geom/Coordinate.h>
 
// Forward declarations
namespace geos {
        namespace geom {
                class CoordinateSequence;
                class Geometry;
                class Polygon;
        }
}
 
namespace geos {
namespace algorithm { // geos::algorithm

class GEOS_DLL CentroidArea {
 
public:
 
        CentroidArea()
                :
                basePt(0.0, 0.0),
                areasum2(0.0),
                totalLength(0.0)
        {}
 
        ~CentroidArea() {}

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

        void add(const geom::CoordinateSequence *ring);
 
        // TODO: deprecate
        geom::Coordinate* getCentroid() const;

        bool getCentroid(geom::Coordinate& ret) const;
 
private:

        geom::Coordinate basePt;
 
        // temporary variable to hold centroid of triangle
        geom::Coordinate triangleCent3;

        double areasum2;       

        geom::Coordinate cg3;
 
        // data for linear centroid computation, if needed
        geom::Coordinate centSum;
        double totalLength;
 
        void setBasePoint(const geom::Coordinate &newbasePt);
 
        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 addLinearSegments(const geom::CoordinateSequence& pts);
 
};
 
} // namespace geos::algorithm
} // namespace geos
 
 
#endif // GEOS_ALGORITHM_CENTROIDAREA_H