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