EdgeComparer.h

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/*
 * $Revision: 2027 $
 * 
 * last checkin:
 *   $Author: gutwenger $ 
 *   $Date: 2010-09-01 11:55:17 +0200 (Wed, 01 Sep 2010) $ 
 ***************************************************************/
 
#ifdef _MSC_VER
#pragma once
#endif


#ifndef OGDF_EDGECOMPARER_H
#define OGDF_EDGECOMPARER_H



#include <ogdf/planarity/PlanRep.h>
#include <ogdf/basic/GraphAttributes.h>

namespace ogdf {


class OGDF_EXPORT EdgeComparer : public VComparer<adjEntry>
{
public:
    //order: clockwise
    
    EdgeComparer(const GraphAttributes& AG, const PlanRep& PR) : 
      m_AG(&AG), m_PR(&PR)
    {}

    EdgeComparer(const GraphAttributes &AG) : m_AG(&AG), m_PR(0) {}

    int compare(const adjEntry &e1, const adjEntry &e2) const;

    bool before(const DPoint u, const DPoint v, const DPoint w) const;
    
private:
    
    int orientation(const DPoint u, 
                    const DPoint v, 
                    const DPoint w) const;

    int compareVectors(const double& x1, 
                        const double& y1, 
                        const double& x2, 
                        const double& y2) const;
    double angle(DPoint p, DPoint q, DPoint r) const;

    inline int signOf(const double& x) const
    { 
        if ( x == 0 ) return 0;
        else if (x > 0 ) return 1;
             else return -1;
    }


    const GraphAttributes *m_AG;
    const PlanRep *m_PR;
};//EdgeComparer


}//namespace ogdf

#endif