sl@0: // Copyright 2004 The Trustees of Indiana University.
sl@0: 
sl@0: // Distributed under the Boost Software License, Version 1.0.
sl@0: // (See accompanying file LICENSE_1_0.txt or copy at
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: 
sl@0: //  Authors: Douglas Gregor
sl@0: //           Andrew Lumsdaine
sl@0: #ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP
sl@0: #define BOOST_GRAPH_CIRCLE_LAYOUT_HPP
sl@0: #include <cmath>
sl@0: #include <utility>
sl@0: #include <boost/graph/graph_traits.hpp>
sl@0: 
sl@0: namespace boost {
sl@0:   /** 
sl@0:    * \brief Layout the graph with the vertices at the points of a regular
sl@0:    * n-polygon. 
sl@0:    *
sl@0:    * The distance from the center of the polygon to each point is
sl@0:    * determined by the @p radius parameter. The @p position parameter
sl@0:    * must be an Lvalue Property Map whose value type is a class type
sl@0:    * containing @c x and @c y members that will be set to the @c x and
sl@0:    * @c y coordinates.
sl@0:    */
sl@0:   template<typename VertexListGraph, typename PositionMap, typename Radius>
sl@0:   void 
sl@0:   circle_graph_layout(const VertexListGraph& g, PositionMap position,
sl@0:                       Radius radius)
sl@0:   {
sl@0:     const double pi = 3.14159;
sl@0: 
sl@0: #ifndef BOOST_NO_STDC_NAMESPACE
sl@0:     using std::sin;
sl@0:     using std::cos;
sl@0: #endif // BOOST_NO_STDC_NAMESPACE
sl@0: 
sl@0:     typedef typename graph_traits<VertexListGraph>::vertices_size_type 
sl@0:       vertices_size_type;
sl@0: 
sl@0:     vertices_size_type n = num_vertices(g);
sl@0:     
sl@0:     typedef typename graph_traits<VertexListGraph>::vertex_iterator 
sl@0:       vertex_iterator;
sl@0: 
sl@0:     vertices_size_type i = 0;
sl@0:     for(std::pair<vertex_iterator, vertex_iterator> v = vertices(g); 
sl@0:         v.first != v.second; ++v.first, ++i) {
sl@0:       position[*v.first].x = radius * cos(i * 2 * pi / n);
sl@0:       position[*v.first].y = radius * sin(i * 2 * pi / n);
sl@0:     }
sl@0:   }
sl@0: } // end namespace boost
sl@0: 
sl@0: #endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP