CGAL 5.4.1 - 2D Arrangements
// Adapting the dual of an arrangement to a BGL graph.
#include <CGAL/config.h>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/graph/visitors.hpp>
#include <CGAL/Arr_extended_dcel.h>
#include <CGAL/graph_traits_dual_arrangement_2.h>
#include <CGAL/Arr_face_index_map.h>
#include "Extended_face_property_map.h"
#include "arr_exact_construction_segments.h"
#include "arr_print.h"
typedef CGAL::Arrangement_2<Traits, Dcel> Ex_arrangement;
typedef CGAL::Dual<Ex_arrangement> Dual_arrangement;
typedef Extended_face_property_map<Ex_arrangement,unsigned int>
int main() {
// Construct an arrangement of seven intersecting line segments.
Point p1(1, 1), p2(1, 4), p3(2, 2), p4(3, 7), p5(4, 4), p6(7, 1), p7(9, 3);
Ex_arrangement arr;
insert(arr, Segment(p1, p6));
insert(arr, Segment(p1, p4)); insert(arr, Segment(p2, p6));
insert(arr, Segment(p3, p7)); insert(arr, Segment(p3, p5));
insert(arr, Segment(p6, p7)); insert(arr, Segment(p4, p7));
// Create a mapping of the arrangement faces to indices.
Face_index_map index_map(arr);
// Perform breadth-first search from the unbounded face, using the event
// visitor to associate each arrangement face with its discover time.
int time = -1;
boost::breadth_first_search(Dual_arrangement(arr), arr.unbounded_face(),
(stamp_times(Face_property_map(), time,
// Print the discover time of each arrangement face.
for (auto fit = arr.faces_begin(); fit != arr.faces_end(); ++fit) {
std::cout << "Discover time " << fit->data() << " for ";
if (fit != arr.unbounded_face()) {
std::cout << "face ";
else std::cout << "the unbounded face.\n";
return 0;