ext/OGDF/ogdf/decomposition/Skeleton.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 Declaration of class Skeleton.
  11  *
  12  * \author Carsten Gutwenger
  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
  49 #ifndef OGDF_SKELETON_H
  50 #define OGDF_SKELETON_H
  51
  52
  53 #include <ogdf/basic/NodeArray.h>
  54 #include <ogdf/basic/EdgeArray.h>
  55
  56
  57 namespace ogdf {
  58
  59         class OGDF_EXPORT SPQRTree;
  60
  61
  62 //! %Skeleton graphs of nodes in an SPQR-tree.
  63 /**
  64  * The class Skeleton maintains the skeleton \a S of a node \a vT in an SPQR-tree
  65  * \a T. We call \a T the owner tree of \a S and \a vT the corresponding tree node. Let
  66  * \a G be the original graph of \a T.
  67  *
  68  * \a S consists of an undirected multi-graph \a M. If the owner tree of \a S is
  69  * a PlanarSPQRTree, then \a M represents a combinatorial embedding.
  70  * The vertices in \a M correspond to vertices in \a G. The edges in \a M are of
  71  * two types: Real edges correspond to edges in \a G and virtual edges correspond
  72  * to tree-edges in \a T having \a vT as an endpoint.
  73  *
  74  * Let \a e in \a M be a virtual edge and \a eT be the corresponding tree-edge.
  75  * Then there exists exactly one edge \a e' in another skeleton \a S' of \a T that
  76  * corresponds to \a eT as well. We call \a e' the twin edge of \a e.
  77  */
  78 class OGDF_EXPORT Skeleton
  79 {
  80 public:
  81
  82         // constructor
  83
  84         //! Creates a skeleton \a S with owner tree \a T and corresponding node \a vT.
  85         /**
  86          * \pre \a vT is a node in \a T
  87          *
  88          * \remarks Skeletons are created by the constructor of SPQRTree
  89          *          and can be accessed with the skeleton() function of SPQRTree.
  90          */
  91         Skeleton(node vT) : m_treeNode(vT) { }
  92
  93
  94         // destructor
  95         virtual ~Skeleton() { }
  96
  97
  98         //! Returns the owner tree \a T.
  99         virtual const SPQRTree &owner() const=0;
 100
 101         //! Returns the corresponding node in the owner tree \a T to which \a S belongs.
 102         node treeNode() const {
 103                 return m_treeNode;
 104         }
 105
 106         //! Returns the reference edge of \a S in \a M.
 107         /**
 108          * The reference edge is a real edge if \a S is the skeleton of the root node
 109          * of \a T, and a virtual edge otherwise.
 110          */
 111         edge referenceEdge() const {
 112                 return m_referenceEdge;
 113         }
 114
 115         //! Returns a reference to the skeleton graph \a M.
 116         const Graph &getGraph() const {
 117                 return m_M;
 118         }
 119
 120         //! Returns a reference to the skeleton graph \a M.
 121         Graph &getGraph() {
 122                 return m_M;
 123         }
 124
 125         //! Returns the vertex in the original graph \a G that corresponds to \a v.
 126         /**
 127          * \pre \a v is a node in \a M.
 128          */
 129         virtual node original (node v) const=0;
 130
 131         //! Returns true iff \a e is a virtual edge.
 132         /**
 133          * \pre \a e is an edge in \a M
 134          */
 135         virtual bool isVirtual (edge e) const=0;
 136
 137         //! Returns the real edge that corresponds to skeleton edge \a e
 138         /**
 139          * If \a e is virtual edge, then 0 is returned.
 140          * \pre \a e is an edge in \a M
 141          */
 142         virtual edge realEdge (edge e) const=0;
 143
 144         //! Returns the twin edge of skeleton edge \a e.
 145         /**
 146          * If \a e is not a virtual edge, then 0 is returned.
 147          * \pre \a e is an edge in \a M
 148          */
 149         virtual edge twinEdge (edge e) const=0;
 150
 151         //! Returns the tree node in T containing the twin edge of skeleton edge \a e.
 152         /**
 153          * If \a e is not a virtual edge, then 0 is returned.
 154          * \pre \a e is an edge in \a M
 155          */
 156         virtual node twinTreeNode (edge e) const=0;
 157
 158         OGDF_NEW_DELETE
 159
 160 protected:
 161         node  m_treeNode;       //!< corresp. tree node in owner tree
 162         edge  m_referenceEdge;  //!< reference edge
 163         Graph m_M;              //!< actual skeleton graph
 164 };
 165
 166
 167 } // end namespace ogdf
 168
 169
 170 #endif