text: /*
   * $Revision: 2523 $
   *
   * last checkin:
   *   $Author: gutwenger $
   *   $Date: 2012-07-02 20:59:27 +0200 (Mon, 02 Jul 2012) $
   ***************************************************************/
  
  /** \file
   * \brief Declaration of class Skeleton.
   *
   * \author Carsten Gutwenger
   *
   * \par License:
   * This file is part of the Open Graph Drawing Framework (OGDF).
   *
   * \par
   * Copyright (C)<br>
   * See README.txt in the root directory of the OGDF installation for details.
   *
   * \par
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * Version 2 or 3 as published by the Free Software Foundation;
   * see the file LICENSE.txt included in the packaging of this file
   * for details.
   *
   * \par
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * \par
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   *
   * \see  http://www.gnu.org/copyleft/gpl.html
   ***************************************************************/
  
  
  #ifdef _MSC_VER
  #pragma once
  #endif
  
  
  #ifndef OGDF_SKELETON_H
  #define OGDF_SKELETON_H
  
  
  #include <ogdf/basic/NodeArray.h>
  #include <ogdf/basic/EdgeArray.h>
  
  
  namespace ogdf {
  
  	class OGDF_EXPORT SPQRTree;
  
  
  //! %Skeleton graphs of nodes in an SPQR-tree.
  /**
   * The class Skeleton maintains the skeleton \a S of a node \a vT in an SPQR-tree
   * \a T. We call \a T the owner tree of \a S and \a vT the corresponding tree node. Let
   * \a G be the original graph of \a T.
   *
   * \a S consists of an undirected multi-graph \a M. If the owner tree of \a S is
   * a PlanarSPQRTree, then \a M represents a combinatorial embedding.
   * The vertices in \a M correspond to vertices in \a G. The edges in \a M are of
   * two types: Real edges correspond to edges in \a G and virtual edges correspond
   * to tree-edges in \a T having \a vT as an endpoint.
   *
   * Let \a e in \a M be a virtual edge and \a eT be the corresponding tree-edge.
   * Then there exists exactly one edge \a e' in another skeleton \a S' of \a T that
   * corresponds to \a eT as well. We call \a e' the twin edge of \a e.
   */
  class OGDF_EXPORT Skeleton
  {
  public:
  
  	// constructor
  
  	//! Creates a skeleton \a S with owner tree \a T and corresponding node \a vT.
  	/**
  	 * \pre \a vT is a node in \a T
  	 *
  	 * \remarks Skeletons are created by the constructor of SPQRTree
  	 *          and can be accessed with the skeleton() function of SPQRTree.
  	 */
  	Skeleton(node vT) : m_treeNode(vT) { }
  
  
  	// destructor
  	virtual ~Skeleton() { }
  
  
  	//! Returns the owner tree \a T.
  	virtual const SPQRTree &owner() const=0;
  
  	//! Returns the corresponding node in the owner tree \a T to which \a S belongs.
  	node treeNode() const {
  		return m_treeNode;
  	}
  
  	//! Returns the reference edge of \a S in \a M.
  	/**
  	 * The reference edge is a real edge if \a S is the skeleton of the root node
  	 * of \a T, and a virtual edge otherwise.
  	 */
  	edge referenceEdge() const {
  		return m_referenceEdge;
  	}
  
  	//! Returns a reference to the skeleton graph \a M.
  	const Graph &getGraph() const {
  		return m_M;
  	}
  
  	//! Returns a reference to the skeleton graph \a M.
  	Graph &getGraph() {
  		return m_M;
  	}
  
  	//! Returns the vertex in the original graph \a G that corresponds to \a v.
  	/**
  	 * \pre \a v is a node in \a M.
  	 */
  	virtual node original (node v) const=0;
  
  	//! Returns true iff \a e is a virtual edge.
  	/**
  	 * \pre \a e is an edge in \a M
  	 */
  	virtual bool isVirtual (edge e) const=0;
  
  	//! Returns the real edge that corresponds to skeleton edge \a e
  	/**
  	 * If \a e is virtual edge, then 0 is returned.
  	 * \pre \a e is an edge in \a M
  	 */
  	virtual edge realEdge (edge e) const=0;
  
  	//! Returns the twin edge of skeleton edge \a e.
  	/**
  	 * If \a e is not a virtual edge, then 0 is returned.
  	 * \pre \a e is an edge in \a M
  	 */
  	virtual edge twinEdge (edge e) const=0;
  
  	//! Returns the tree node in T containing the twin edge of skeleton edge \a e.
  	/**
  	 * If \a e is not a virtual edge, then 0 is returned.
  	 * \pre \a e is an edge in \a M
  	 */
  	virtual node twinTreeNode (edge e) const=0;
  
  	OGDF_NEW_DELETE
  
  protected:
  	node  m_treeNode;       //!< corresp. tree node in owner tree
  	edge  m_referenceEdge;  //!< reference edge
  	Graph m_M;              //!< actual skeleton graph
  };
  
  
  } // end namespace ogdf
  
  
  #endif
  