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//=======================================================================
// Copyright 2007 Aaron Windsor
//
// 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)
//=======================================================================
#include <iostream>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/properties.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/ref.hpp>
#include <vector>
#include <boost/graph/make_biconnected_planar.hpp>
#include <boost/graph/make_maximal_planar.hpp>
#include <boost/graph/planar_face_traversal.hpp>
#include <boost/graph/boyer_myrvold_planar_test.hpp>
// This example shows how to start with a connected planar graph
// and add edges to make the graph maximal planar (triangulated.)
// Any maximal planar simple graph on n vertices has 3n - 6 edges and
// 2n - 4 faces, a consequence of Euler's formula.
using namespace boost;
// This visitor is passed to planar_face_traversal to count the
// number of faces.
struct face_counter : public planar_face_traversal_visitor
{
face_counter() : count(0) {}
void begin_face() { ++count; }
int count;
};
int main(int argc, char** argv)
{
typedef adjacency_list< vecS, vecS, undirectedS,
property< vertex_index_t, int >, property< edge_index_t, int > >
graph;
// Create the graph - a straight line
graph g(10);
add_edge(0, 1, g);
add_edge(1, 2, g);
add_edge(2, 3, g);
add_edge(3, 4, g);
add_edge(4, 5, g);
add_edge(5, 6, g);
add_edge(6, 7, g);
add_edge(7, 8, g);
add_edge(8, 9, g);
std::cout << "Since the input graph is planar with " << num_vertices(g)
<< " vertices," << std::endl
<< "The output graph should be planar with "
<< 3 * num_vertices(g) - 6 << " edges and "
<< 2 * num_vertices(g) - 4 << " faces." << std::endl;
// Initialize the interior edge index
property_map< graph, edge_index_t >::type e_index = get(edge_index, g);
graph_traits< graph >::edges_size_type edge_count = 0;
graph_traits< graph >::edge_iterator ei, ei_end;
for (boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
put(e_index, *ei, edge_count++);
// Test for planarity; compute the planar embedding as a side-effect
typedef std::vector< graph_traits< graph >::edge_descriptor > vec_t;
std::vector< vec_t > embedding(num_vertices(g));
if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
boyer_myrvold_params::embedding = &embedding[0]))
std::cout << "Input graph is planar" << std::endl;
else
std::cout << "Input graph is not planar" << std::endl;
make_biconnected_planar(g, &embedding[0]);
// Re-initialize the edge index, since we just added a few edges
edge_count = 0;
for (boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
put(e_index, *ei, edge_count++);
// Test for planarity again; compute the planar embedding as a side-effect
if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
boyer_myrvold_params::embedding = &embedding[0]))
std::cout << "After calling make_biconnected, the graph is still planar"
<< std::endl;
else
std::cout << "After calling make_biconnected, the graph is not planar"
<< std::endl;
make_maximal_planar(g, &embedding[0]);
// Re-initialize the edge index, since we just added a few edges
edge_count = 0;
for (boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
put(e_index, *ei, edge_count++);
// Test for planarity one final time; compute the planar embedding as a
// side-effect
std::cout << "After calling make_maximal_planar, the final graph ";
if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
boyer_myrvold_params::embedding = &embedding[0]))
std::cout << "is planar." << std::endl;
else
std::cout << "is not planar." << std::endl;
std::cout << "The final graph has " << num_edges(g) << " edges."
<< std::endl;
face_counter count_visitor;
planar_face_traversal(g, &embedding[0], count_visitor);
std::cout << "The final graph has " << count_visitor.count << " faces."
<< std::endl;
return 0;
}
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