1 // Copyright 2004 The Trustees of Indiana University. 2 3 // Distributed under the Boost Software License, Version 1.0. 4 // (See accompanying file LICENSE_1_0.txt or copy at 5 // http://www.boost.org/LICENSE_1_0.txt) 6 7 // Authors: Douglas Gregor 8 // Andrew Lumsdaine 9 #ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP 10 #define BOOST_GRAPH_CIRCLE_LAYOUT_HPP 11 #include <boost/config/no_tr1/cmath.hpp> 12 #include <boost/math/constants/constants.hpp> 13 #include <utility> 14 #include <boost/graph/graph_traits.hpp> 15 #include <boost/graph/iteration_macros.hpp> 16 #include <boost/graph/topology.hpp> 17 #include <boost/static_assert.hpp> 18 19 namespace boost 20 { 21 /** 22 * \brief Layout the graph with the vertices at the points of a regular 23 * n-polygon. 24 * 25 * The distance from the center of the polygon to each point is 26 * determined by the @p radius parameter. The @p position parameter 27 * must be an Lvalue Property Map whose value type is a class type 28 * containing @c x and @c y members that will be set to the @c x and 29 * @c y coordinates. 30 */ 31 template < typename VertexListGraph, typename PositionMap, typename Radius > circle_graph_layout(const VertexListGraph & g,PositionMap position,Radius radius)32void circle_graph_layout( 33 const VertexListGraph& g, PositionMap position, Radius radius) 34 { 35 BOOST_STATIC_ASSERT( 36 property_traits< PositionMap >::value_type::dimensions >= 2); 37 const double pi = boost::math::constants::pi< double >(); 38 39 #ifndef BOOST_NO_STDC_NAMESPACE 40 using std::cos; 41 using std::sin; 42 #endif // BOOST_NO_STDC_NAMESPACE 43 44 typedef typename graph_traits< VertexListGraph >::vertices_size_type 45 vertices_size_type; 46 47 vertices_size_type n = num_vertices(g); 48 49 vertices_size_type i = 0; 50 double two_pi_over_n = 2. * pi / n; 51 BGL_FORALL_VERTICES_T(v, g, VertexListGraph) 52 { 53 position[v][0] = radius * cos(i * two_pi_over_n); 54 position[v][1] = radius * sin(i * two_pi_over_n); 55 ++i; 56 } 57 } 58 } // end namespace boost 59 60 #endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP 61