ext/OGDF/ogdf/internal/energybased/Attraction.h

   1 /*
   2  * $Revision: 2523 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-02 20:59:27 +0200 (Mon, 02 Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Declares 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
  44 #ifdef _MSC_VER
  45 #pragma once
  46 #endif
  47
  48 #ifndef OGDF_ATTRACTION_H
  49 #define OGDF_ATTRACTION_H
  50
  51
  52 #include <ogdf/internal/energybased/NodePairEnergy.h>
  53
  54 namespace ogdf {
  55
  56
  57 //! Energy function for attraction between two adjacent vertices.
  58 /**
  59  * Implements an energy function that simulates
  60  * attraction between two adjacent vertices. There is an optimum
  61  * distance where the energy is zero. The energy grows quadratic
  62  * with the difference to the optimum distance. The optimum
  63  * distance between two adjacent vertices depends on the size of
  64  * the two vertices.
  65  */
  66 class Attraction: public NodePairEnergy {
  67 public:
  68                 //Initializes data structures to speed up later computations
  69                 Attraction(GraphAttributes &AG);
  70                 ~Attraction() {}
  71                 //! set the preferred edge length to the absolute value l
  72                 void setPreferredEdgelength(double l) {m_preferredEdgeLength = l;}
  73                 //! set multiplier for the edge length with repspect to node size to multi
  74                 void reinitializeEdgeLength(double multi);
  75 #ifdef OGDF_DEBUG
  76                 void printInternalData() const;
  77 #endif
  78 private:
  79         //! Average length and height of nodes is multiplied by this factor to get preferred edge length
  80         static const double MULTIPLIER;
  81         //! the length that that all edges should ideally have
  82         double m_preferredEdgeLength;
  83         //! computes the energy contributed by the two nodes if they are placed at the two given positions
  84         double computeCoordEnergy(node,node, const DPoint&, const DPoint &) const;
  85 };
  86
  87 }// namespace ogdf
  88
  89 #endif