boost/graph/chrobak_payne_drawing.hpp

//=======================================================================
// Copyright (c) Aaron Windsor 2007
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================

#ifndef __CHROBAK_PAYNE_DRAWING_HPP__
#define __CHROBAK_PAYNE_DRAWING_HPP__

#include <vector>
#include <list>
#include <boost/config.hpp>
#include <boost/utility.hpp>  //for next and prior
#include <boost/graph/graph_traits.hpp>
#include <boost/property_map/property_map.hpp>


namespace boost
{

  namespace graph { namespace detail
  {

    template<typename Graph, 
             typename VertexToVertexMap, 
             typename VertexTo1DCoordMap>
    void accumulate_offsets(typename graph_traits<Graph>::vertex_descriptor v,
                            std::size_t offset,
                            const Graph& g,
                            VertexTo1DCoordMap x,
                            VertexTo1DCoordMap delta_x,
                            VertexToVertexMap left,
                            VertexToVertexMap right)
    {
      if (v != graph_traits<Graph>::null_vertex())
        {
          x[v] += delta_x[v] + offset;
          accumulate_offsets(left[v], x[v], g, x, delta_x, left, right);
          accumulate_offsets(right[v], x[v], g, x, delta_x, left, right);
        }
    }

  } /*namespace detail*/ } /*namespace graph*/





  template<typename Graph, 
           typename PlanarEmbedding, 
           typename ForwardIterator, 
           typename GridPositionMap,
           typename VertexIndexMap>
  void chrobak_payne_straight_line_drawing(const Graph& g, 
                                           PlanarEmbedding embedding, 
                                           ForwardIterator ordering_begin,
                                           ForwardIterator ordering_end,
                                           GridPositionMap drawing,
                                           VertexIndexMap vm
                                           )
  {

    typedef typename graph_traits<Graph>::vertex_descriptor vertex_t;
    typedef typename graph_traits<Graph>::edge_descriptor edge_t;
    typedef typename graph_traits<Graph>::vertex_iterator vertex_iterator_t;
    typedef typename PlanarEmbedding::value_type::const_iterator 
      edge_permutation_iterator_t;
    typedef typename graph_traits<Graph>::vertices_size_type v_size_t;
    typedef std::vector<vertex_t> vertex_vector_t;
    typedef std::vector<v_size_t> vsize_vector_t;
    typedef std::vector<bool> bool_vector_t;
    typedef boost::iterator_property_map
      <typename vertex_vector_t::iterator, VertexIndexMap> 
      vertex_to_vertex_map_t;
    typedef boost::iterator_property_map
      <typename vsize_vector_t::iterator, VertexIndexMap> 
      vertex_to_vsize_map_t;
    typedef boost::iterator_property_map
      <typename bool_vector_t::iterator, VertexIndexMap> 
      vertex_to_bool_map_t;

    vertex_vector_t left_vector(num_vertices(g), 
                                graph_traits<Graph>::null_vertex()
                                );
    vertex_vector_t right_vector(num_vertices(g), 
                                 graph_traits<Graph>::null_vertex()
                                 );
    vsize_vector_t seen_as_right_vector(num_vertices(g), 0);
    vsize_vector_t seen_vector(num_vertices(g), 0);
    vsize_vector_t delta_x_vector(num_vertices(g),0);
    vsize_vector_t y_vector(num_vertices(g));
    vsize_vector_t x_vector(num_vertices(g),0);
    bool_vector_t installed_vector(num_vertices(g),false);

    vertex_to_vertex_map_t left(left_vector.begin(), vm);
    vertex_to_vertex_map_t right(right_vector.begin(), vm);
    vertex_to_vsize_map_t seen_as_right(seen_as_right_vector.begin(), vm);
    vertex_to_vsize_map_t seen(seen_vector.begin(), vm);
    vertex_to_vsize_map_t delta_x(delta_x_vector.begin(), vm);
    vertex_to_vsize_map_t y(y_vector.begin(), vm);
    vertex_to_vsize_map_t x(x_vector.begin(), vm);
    vertex_to_bool_map_t installed(installed_vector.begin(), vm);

    v_size_t timestamp = 1;
    vertex_vector_t installed_neighbors;

    ForwardIterator itr = ordering_begin;
    vertex_t v1 = *itr; ++itr;
    vertex_t v2 = *itr; ++itr;
    vertex_t v3 = *itr; ++itr;

    delta_x[v2] = 1; 
    delta_x[v3] = 1;
    
    y[v1] = 0;
    y[v2] = 0;
    y[v3] = 1;

    right[v1] = v3;
    right[v3] = v2;

    installed[v1] = installed[v2] = installed[v3] = true;

    for(ForwardIterator itr_end = ordering_end; itr != itr_end; ++itr)
      {
        vertex_t v = *itr;

        // First, find the leftmost and rightmost neighbor of v on the outer 
        // cycle of the embedding. 
        // Note: since we're moving clockwise through the edges adjacent to v, 
        // we're actually moving from right to left among v's neighbors on the
        // outer face (since v will be installed above them all) looking for 
        // the leftmost and rightmost installed neigbhors

        vertex_t leftmost = graph_traits<Graph>::null_vertex();
        vertex_t rightmost = graph_traits<Graph>::null_vertex();

        installed_neighbors.clear();

        vertex_t prev_vertex = graph_traits<Graph>::null_vertex();
        edge_permutation_iterator_t pi, pi_end;
        pi_end = embedding[v].end();
        for(pi = embedding[v].begin(); pi != pi_end; ++pi)
          {
            vertex_t curr_vertex = source(*pi,g) == v ? 
              target(*pi,g) : source(*pi,g);
            
            // Skip any self-loops or parallel edges
            if (curr_vertex == v || curr_vertex == prev_vertex)
                continue;

            if (installed[curr_vertex])
              {
                seen[curr_vertex] = timestamp;

                if (right[curr_vertex] != graph_traits<Graph>::null_vertex())
                  {
                    seen_as_right[right[curr_vertex]] = timestamp;
                  }
                installed_neighbors.push_back(curr_vertex);
              }

            prev_vertex = curr_vertex;
          }

        typename vertex_vector_t::iterator vi, vi_end;
        vi_end = installed_neighbors.end();
        for(vi = installed_neighbors.begin(); vi != vi_end; ++vi)
          {
            if (right[*vi] == graph_traits<Graph>::null_vertex() || 
                seen[right[*vi]] != timestamp
                )
              rightmost = *vi;
            if (seen_as_right[*vi] != timestamp)
              leftmost = *vi;
          }

        ++timestamp;

        //stretch gaps
        ++delta_x[right[leftmost]];
        ++delta_x[rightmost];

        //adjust offsets
        std::size_t delta_p_q = 0;
        vertex_t stopping_vertex = right[rightmost];
        for(vertex_t temp = right[leftmost]; temp != stopping_vertex; 
            temp = right[temp]
            )
          {
            delta_p_q += delta_x[temp];
          }

        delta_x[v] = ((y[rightmost] + delta_p_q) - y[leftmost])/2;
        y[v] = y[leftmost] + delta_x[v];
        delta_x[rightmost] = delta_p_q - delta_x[v];
        
        bool leftmost_and_rightmost_adjacent = right[leftmost] == rightmost;
        if (!leftmost_and_rightmost_adjacent)
          delta_x[right[leftmost]] -= delta_x[v];

        //install v
        if (!leftmost_and_rightmost_adjacent)
          {
            left[v] = right[leftmost];
            vertex_t next_to_rightmost;
            for(vertex_t temp = leftmost; temp != rightmost; 
                temp = right[temp]
                )
              {
                next_to_rightmost = temp;
              }

            right[next_to_rightmost] = graph_traits<Graph>::null_vertex();
          }
        else
          {
            left[v] = graph_traits<Graph>::null_vertex();
          }

        right[leftmost] = v;
        right[v] = rightmost;
        installed[v] = true;

      }

    graph::detail::accumulate_offsets
      (*ordering_begin,0,g,x,delta_x,left,right);

    vertex_iterator_t vi, vi_end;
    for(tie(vi,vi_end) = vertices(g); vi != vi_end; ++vi)
      {
        vertex_t v(*vi);
        drawing[v].x = x[v];
        drawing[v].y = y[v];
      }

  }




  template<typename Graph, 
           typename PlanarEmbedding, 
           typename ForwardIterator, 
           typename GridPositionMap>
  inline void chrobak_payne_straight_line_drawing(const Graph& g, 
                                                  PlanarEmbedding embedding, 
                                                  ForwardIterator ord_begin,
                                                  ForwardIterator ord_end,
                                                  GridPositionMap drawing
                                                  )
  {
    chrobak_payne_straight_line_drawing(g, 
                                        embedding, 
                                        ord_begin, 
                                        ord_end, 
                                        drawing, 
                                        get(vertex_index,g)
                                        );
  }


  

} // namespace boost

#endif //__CHROBAK_PAYNE_DRAWING_HPP__