Quantum GIS API Documentation  1.7.4
src/core/qgscentralpointpositionmanager.h
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00001 /***************************************************************************
00002                          qgscentralpointpositionmanager.h  -  description
00003                          --------------------------------
00004     begin                : January 2007
00005     copyright            : (C) 2007 by Marco Hugentobler
00006     email                : marco dot hugentobler at karto dot baug dot ethz dot ch
00007  ***************************************************************************/
00008 
00009 /***************************************************************************
00010  *                                                                         *
00011  *   This program is free software; you can redistribute it and/or modify  *
00012  *   it under the terms of the GNU General Public License as published by  *
00013  *   the Free Software Foundation; either version 2 of the License, or     *
00014  *   (at your option) any later version.                                   *
00015  *                                                                         *
00016  ***************************************************************************/
00017 
00018 #ifndef QGSCENTRALPOINTPOSITIONMANAGER
00019 #define QGSCENTRALPOINTPOSITIONMANAGER
00020 
00021 #include "qgsoverlayobjectpositionmanager.h"
00022 #include "qgsrendercontext.h"
00023 
00024 class QgsPoint;
00025 
00030 class QgsCentralPointPositionManager: public QgsOverlayObjectPositionManager
00031 {
00032   public:
00033     QgsCentralPointPositionManager();
00034     ~QgsCentralPointPositionManager();
00035     void addLayer( QgsVectorLayer* vl, QList<QgsVectorOverlay*>& overlays );
00037     void removeLayers();
00038     void findObjectPositions( const QgsRenderContext& context, QGis::UnitType unitType );
00039 
00040   private:
00042     int findObjectPosition( const unsigned char* wkb, QgsPoint& position ) const;
00045     int calculatePolygonCentroid( double x[], double y[], int numberOfPoints, double& centroidX, double& centroidY ) const;
00046 
00048     QList<QgsVectorOverlay*> mOverlays;
00049 };
00050 
00051 #endif
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