CentroidArea.h

00001 /**********************************************************************
00002  * $Id: CentroidArea.h 1820 2006-09-06 16:54:23Z mloskot $
00003  *
00004  * GEOS - Geometry Engine Open Source
00005  * http://geos.refractions.net
00006  *
00007  * Copyright (C) 2005-2006 Refractions Research Inc.
00008  * Copyright (C) 2001-2002 Vivid Solutions Inc.
00009  *
00010  * This is free software; you can redistribute and/or modify it under
00011  * the terms of the GNU Lesser General Public Licence as published
00012  * by the Free Software Foundation. 
00013  * See the COPYING file for more information.
00014  *
00015  **********************************************************************/
00016 
00017 #ifndef GEOS_ALGORITHM_CENTROIDAREA_H
00018 #define GEOS_ALGORITHM_CENTROIDAREA_H
00019 
00020 
00021 #include <geos/geom/Coordinate.h>
00022 
00023 // Forward declarations
00024 namespace geos {
00025         namespace geom {
00026                 class CoordinateSequence;
00027                 class Geometry;
00028                 class Polygon;
00029         }
00030 }
00031 
00032 namespace geos {
00033 namespace algorithm { // geos::algorithm
00034 
00049 class CentroidArea {
00050 
00051 public:
00052 
00053         CentroidArea()
00054                 :
00055                 basePt(0.0, 0.0),
00056                 areasum2(0)
00057         {}
00058 
00059         ~CentroidArea() {}
00060 
00067         void add(const geom::Geometry *geom);
00068 
00075         void add(const geom::CoordinateSequence *ring);
00076 
00077         geom::Coordinate* getCentroid() const;
00078 
00080         bool getCentroid(geom::Coordinate& ret) const;
00081 
00082 private:
00083 
00085         geom::Coordinate basePt;
00086 
00087         // temporary variable to hold centroid of triangle
00088         geom::Coordinate triangleCent3;
00089 
00091         double areasum2;       
00092 
00094         geom::Coordinate cg3;
00095 
00096         void setBasePoint(const geom::Coordinate &newbasePt);
00097 
00098         void add(const geom::Polygon *poly);
00099 
00100         void addShell(const geom::CoordinateSequence *pts);
00101 
00102         void addHole(const geom::CoordinateSequence *pts);
00103         
00104         void addTriangle(const geom::Coordinate &p0, const geom::Coordinate &p1,
00105                         const geom::Coordinate &p2,bool isPositiveArea);
00106 
00107         static void centroid3(const geom::Coordinate &p1, const geom::Coordinate &p2,
00108                         const geom::Coordinate &p3, geom::Coordinate &c);
00109 
00110         static double area2(const geom::Coordinate &p1, const geom::Coordinate &p2,
00111                         const geom::Coordinate &p3);
00112 
00113 };
00114 
00115 } // namespace geos::algorithm
00116 } // namespace geos
00117 
00118 
00119 #endif // GEOS_ALGORITHM_CENTROIDAREA_H
00120 
00121 /**********************************************************************
00122  * $Log$
00123  * Revision 1.1  2006/03/09 16:46:48  strk
00124  * geos::geom namespace definition, first pass at headers split
00125  *
00126  **********************************************************************/
00127 

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