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// Copyright 2004 The Trustees of Indiana University.
// 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)
// Authors: Douglas Gregor
// Andrew Lumsdaine
#ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP
#define BOOST_GRAPH_CIRCLE_LAYOUT_HPP
#include <boost/config/no_tr1/cmath.hpp>
#include <boost/math/constants/constants.hpp>
#include <utility>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/iteration_macros.hpp>
#include <boost/graph/topology.hpp>
#include <boost/static_assert.hpp>
namespace boost {
/**
* \brief Layout the graph with the vertices at the points of a regular
* n-polygon.
*
* The distance from the center of the polygon to each point is
* determined by the @p radius parameter. The @p position parameter
* must be an Lvalue Property Map whose value type is a class type
* containing @c x and @c y members that will be set to the @c x and
* @c y coordinates.
*/
template<typename VertexListGraph, typename PositionMap, typename Radius>
void
circle_graph_layout(const VertexListGraph& g, PositionMap position,
Radius radius)
{
BOOST_STATIC_ASSERT (property_traits<PositionMap>::value_type::dimensions >= 2);
const double pi = boost::math::constants::pi<double>();
#ifndef BOOST_NO_STDC_NAMESPACE
using std::sin;
using std::cos;
#endif // BOOST_NO_STDC_NAMESPACE
typedef typename graph_traits<VertexListGraph>::vertices_size_type
vertices_size_type;
vertices_size_type n = num_vertices(g);
vertices_size_type i = 0;
double two_pi_over_n = 2. * pi / n;
BGL_FORALL_VERTICES_T(v, g, VertexListGraph) {
position[v][0] = radius * cos(i * two_pi_over_n);
position[v][1] = radius * sin(i * two_pi_over_n);
++i;
}
}
} // end namespace boost
#endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP