ext/OGDF/src/energybased/Attraction.cpp

   1 /*
   2  * $Revision: 2552 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-05 16:45:20 +0200 (Do, 05. Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Implements class Attraction.
  11  *
  12  * \author Rene Weiskircher
  13  *
  14  * \par License:
  15  * This file is part of the Open Graph Drawing Framework (OGDF).
  16  *
  17  * \par
  18  * Copyright (C)<br>
  19  * See README.txt in the root directory of the OGDF installation for details.
  20  *
  21  * \par
  22  * This program is free software; you can redistribute it and/or
  23  * modify it under the terms of the GNU General Public License
  24  * Version 2 or 3 as published by the Free Software Foundation;
  25  * see the file LICENSE.txt included in the packaging of this file
  26  * for details.
  27  *
  28  * \par
  29  * This program is distributed in the hope that it will be useful,
  30  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  31  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  32  * GNU General Public License for more details.
  33  *
  34  * \par
  35  * You should have received a copy of the GNU General Public
  36  * License along with this program; if not, write to the Free
  37  * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  38  * Boston, MA 02110-1301, USA.
  39  *
  40  * \see  http://www.gnu.org/copyleft/gpl.html
  41  ***************************************************************/
  42
  43 #include <ogdf/internal/energybased/Attraction.h>
  44
  45 namespace ogdf {
  46
  47 const double Attraction::MULTIPLIER = 2.0;
  48
  49
  50 //initializes internal data, like name and layout
  51 Attraction::Attraction(GraphAttributes &AG) : NodePairEnergy("Attraction", AG) {
  52
  53         reinitializeEdgeLength(MULTIPLIER);
  54 }
  55
  56
  57 //computes preferred edge length as the average of all widths and heights of the vertices
  58 //multiplied by the multiplier
  59 void Attraction::reinitializeEdgeLength(double multi)
  60 {
  61         double lengthSum(0.0);
  62         node v;
  63         forall_nodes(v,m_G) {
  64                 const IntersectionRectangle &i = shape(v);
  65                 lengthSum += i.width();
  66                 lengthSum += i.height();
  67         }
  68         lengthSum /= (2*m_G.numberOfNodes());
  69         // lengthSum is now the average of all lengths and widths
  70         m_preferredEdgeLength = multi * lengthSum;
  71
  72 }//reinitializeEdgeLength
  73
  74
  75 //the energy of a pair of vertices is computed as the square of the difference between the
  76 //actual distance and the preferred edge length
  77 double Attraction::computeCoordEnergy(node v1, node v2, const DPoint &p1, const DPoint &p2)
  78 const
  79 {
  80         double energy = 0.0;
  81         if(adjacent(v1,v2)) {
  82                 IntersectionRectangle i1(shape(v1)), i2(shape(v2));
  83                 i1.move(p1);
  84                 i2.move(p2);
  85                 energy = i1.distance(i2) - m_preferredEdgeLength;
  86                 energy *= energy;
  87         }
  88         return energy;
  89 }
  90
  91
  92 #ifdef OGDF_DEBUG
  93 void Attraction::printInternalData() const {
  94         NodePairEnergy::printInternalData();
  95         cout << "\nPreferred edge length: " << m_preferredEdgeLength;
  96 }
  97 #endif
  98
  99 }// namespace ogdf