CGAL 5.5.2 - 2D Arrangements
Arrangement_on_surface_2/face_extension_overlay.cpp
// A face overlay of two arrangements with extended face records.
#include <cassert>
#include <CGAL/basic.h>
#include <CGAL/Arr_overlay_2.h>
#include <CGAL/Arr_default_overlay_traits.h>
#include "arr_exact_construction_segments.h"
typedef CGAL::Arrangement_2<Traits, Dcel> Ex_arrangement;
typedef CGAL::Arr_face_overlay_traits<Ex_arrangement, Ex_arrangement,
Ex_arrangement,
std::logical_and<bool> >
Overlay_traits;
int main() {
// Construct the first arrangement, containing a square-shaped face.
Ex_arrangement arr1;
insert_non_intersecting_curve(arr1, Segment(Point(2, 2), Point(6, 2)));
insert_non_intersecting_curve(arr1, Segment(Point(6, 2), Point(6, 6)));
insert_non_intersecting_curve(arr1, Segment(Point(6, 6), Point(2, 6)));
insert_non_intersecting_curve(arr1, Segment(Point(2, 6), Point(2, 2)));
// 2 because the bounded and the unbounded one
assert(arr1.number_of_faces() == 2);
// Mark just the bounded face.
for (auto fit = arr1.faces_begin(); fit != arr1.faces_end(); ++fit)
fit->set_data(fit != arr1.unbounded_face());
// Construct the second arrangement, containing a rhombus-shaped face.
Ex_arrangement arr2;
insert_non_intersecting_curve(arr2, Segment(Point(4, 1), Point(7, 4)));
insert_non_intersecting_curve(arr2, Segment(Point(7, 4), Point(4, 7)));
insert_non_intersecting_curve(arr2, Segment(Point(4, 7), Point(1, 4)));
insert_non_intersecting_curve(arr2, Segment(Point(1, 4), Point(4, 1)));
for (auto fit = arr2.faces_begin(); fit != arr2.faces_end(); ++fit)
fit->set_data(fit != arr2.unbounded_face()); // mark the bounded face.
// Compute the overlay of the two arrangements, marking only the faces that
// are intersections of two marked faces in arr1 and arr2, respectively.
Ex_arrangement overlay_arr;
Overlay_traits overlay_traits;
CGAL::overlay(arr1, arr2, overlay_arr, overlay_traits);
// Go over the faces of the resulting arrangement and print the marked ones.
std::cout << "The intersection is: ";
for (auto fit = overlay_arr.faces_begin(); fit != overlay_arr.faces_end();
++fit)
{
if (! fit->data()) continue;
Ex_arrangement::Ccb_halfedge_circulator curr = fit->outer_ccb();
std::cout << curr->source()->point();
do std::cout << " --> " << curr->target()->point();
while (++curr != fit->outer_ccb());
std::cout << std::endl;
}
return 0;
}