FruchtermanReingold.h

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/*
 * $Revision: 2299 $
 * 
 * last checkin:
 *   $Author: gutwenger $ 
 *   $Date: 2012-05-07 15:57:08 +0200 (Mon, 07 May 2012) $ 
 ***************************************************************/
 
#ifdef _MSC_VER
#pragma once
#endif

#ifndef OGDF_FRUCHTERMAN_REINGOLD_H
#define OGDF_FRUCHTERMAN_REINGOLD_H

#include <ogdf/basic/Graph.h>
#include <ogdf/basic/geometry.h>
#include <ogdf/basic/NodeArray.h>
#include <ogdf/internal/energybased/NodeAttributes.h>
#include <ogdf/internal/energybased/EdgeAttributes.h>

namespace ogdf {

class OGDF_EXPORT FruchtermanReingold 
{
   
   
   public:
      FruchtermanReingold();          //constructor
      ~FruchtermanReingold();         //destructor

      //Calculate exact rep. forces for each node. 
      void calculate_exact_repulsive_forces(const Graph &G,NodeArray<NodeAttributes>& A,
                                      NodeArray<DPoint>& F_rep);

      //Grid approximation of rep.forces for each node. 
      void calculate_approx_repulsive_forces(const Graph &G,NodeArray<NodeAttributes>&
                         A, NodeArray<DPoint>& F_rep);

      //Make all initialisations that are needed for FruchtermanReingold.
      void make_initialisations (double boxlength,DPoint down_left_corner,int grid_quotient);

      //Import updated information of the drawing area.
      void update_boxlength_and_cornercoordinate(double b_l,DPoint d_l_c)
           { boxlength = b_l; down_left_corner = d_l_c;}

   private:
      int _grid_quotient;//for coarsening the FrRe-grid
      int max_gridindex; //maximum index of a grid row/column
      double boxlength;  //length of drawing box
      DPoint down_left_corner;//down left corner of drawing box

      //Returns the repulsing force_function_value of scalar d.
      double f_rep_scalar (double d);
      
      //The number k of rows and colums of the grid is sqrt(|V|) / frGridQuotient()  
      //(Note that in [FrRe] frGridQuotient() is 2.) 
      void grid_quotient(int p) { _grid_quotient = ((0<=p) ? p : 2);}
      int grid_quotient() const {return _grid_quotient;}

};
}//namespace ogdf
#endif