Face_index_observer (Arrangement_2& arr) :
CGAL::Arr_observer<Arrangement_2> (arr),
n_faces (0)
{
CGAL_precondition (arr.is_empty());
arr.unbounded_face()->set_data (0);
n_faces++;
}
int main()
{
// Step(a) - construct a triangular face.
Arrangement_2 arr;
Segment_2 s1(Point_2(667, 1000), Point_2(4000, 5000));
Segment_2 s2(Point_2(4000, 0), Point_2(4000, 5000));
Segment_2 s3(Point_2(667, 1000), Point_2(4000, 0));
Halfedge_handle e1 = arr.insert_in_face_interior(s1, arr.unbounded_face());
Vertex_handle v1 = e1->source();
Vertex_handle v2 = e1->target();
Halfedge_handle e2 = arr.insert_from_right_vertex(s2, v2);
Vertex_handle v3 = e2->target();
arr.insert_at_vertices(s3, v3, v1);
// Step (b) - create additional two faces inside the triangle.
Point_2 p1(4000, 3666), p2(4000, 1000);
Segment_2 s4(Point_2(4000, 5000), p1);
Segment_2 s5(p1, p2);
Segment_2 s6(Point_2(4000, 0), p2);
Halfedge_handle e4 = arr.split_edge(e2, s4, Segment_2(Point_2(4000, 0), p1));
Vertex_handle w1 = e4->target();
Halfedge_handle e5 = arr.split_edge(e4->next(), s5, s6);
Vertex_handle w2 = e5->target();
Halfedge_handle e6 = e5->next();
Segment_2 s7(p1, Point_2(3000, 2666));
Segment_2 s8(p2, Point_2(3000, 1333));
Segment_2 s9(Point_2(3000, 2666), Point_2(2000, 1666));
Segment_2 s10(Point_2(3000, 1333), Point_2(2000, 1666));
Segment_2 s11(Point_2(3000, 1333), Point_2(3000, 2666));
Halfedge_handle e7 = arr.insert_from_right_vertex(s7, w1);
Vertex_handle v4 = e7->target();
Halfedge_handle e8 = arr.insert_from_right_vertex(s8, w2);
Vertex_handle v5 = e8->target();
Vertex_handle v6 =
arr.insert_in_face_interior(Point_2(2000, 1666), e8->face());
arr.insert_at_vertices(s9, v4, v6);
arr.insert_at_vertices(s10, v5, v6);
arr.insert_at_vertices(s11, v4, v5);
// Step(c) - remove and merge faces to form a single hole in the traingle.
arr.remove_edge(e7);
arr.remove_edge(e8);
e5 = arr.merge_edge(e5, e6, Segment_2(e5->source()->point(),
e6->target()->point()));
e2 = arr.merge_edge(e4, e5, s2);
print_arrangement(arr);
return 0;
}
int main ()
{
Arrangement_2 arr;
// Construct an arrangement of seven intersecting line segments.
insert (arr, Segment_2 (Point_2 (1, 1), Point_2 (7, 1)));
insert (arr, Segment_2 (Point_2 (1, 1), Point_2 (3, 7)));
insert (arr, Segment_2 (Point_2 (1, 4), Point_2 (7, 1)));
insert (arr, Segment_2 (Point_2 (2, 2), Point_2 (9, 3)));
insert (arr, Segment_2 (Point_2 (2, 2), Point_2 (4, 4)));
insert (arr, Segment_2 (Point_2 (7, 1), Point_2 (9, 3)));
insert (arr, Segment_2 (Point_2 (3, 7), Point_2 (9, 3)));
// Create a mapping of the arrangement faces to indices.
CGAL::Arr_face_index_map<Arrangement_2> index_map (arr);
// Perform breadth-first search from the unbounded face, and use the BFS
// visitor to associate each arrangement face with its discover time.
Discover_time_bfs_visitor<CGAL::Arr_face_index_map<Arrangement_2> >
bfs_visitor (index_map);
Arrangement_2::Face_handle uf = arr.unbounded_face();
boost::breadth_first_search (Dual_arrangement_2 (arr), uf,
boost::vertex_index_map (index_map).
visitor (bfs_visitor));
// Print the results:
Arrangement_2::Face_iterator fit;
for (fit = arr.faces_begin(); fit != arr.faces_end(); ++fit)
{
std::cout << "Discover time " << fit->data() << " for ";
if (fit != uf)
{
std::cout << "face ";
print_ccb<Arrangement_2> (fit->outer_ccb());
}
else
std::cout << "the unbounded face." << std::endl;
}
return (0);
}
int main()
{
Arrangement_2 arr;
// Construct an arrangement of five linear objects.
std::vector<X_monotone_curve_2> curves;
curves.push_back(Ray_2(Point_2(0, 0), Point_2(0, 1)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(1, 0)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(0, -1)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(-1, 0)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(1, 1)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(1, -1)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(-1, 1)));
curves.push_back(Ray_2(Point_2(0, 0), Point_2(-1, -1)));
std::vector<Halfedge_handle> hhs(curves.size());
for (size_t i = 0; i < curves.size(); i++)
hhs[i] = insert_non_intersecting_curve(arr, curves[i]);
bool valid = arr.is_valid();
std::cout << "Arrangement size:"
<< " V = " << arr.number_of_vertices()
<< ", E = " << arr.number_of_edges()
<< ", F = " << arr.number_of_faces() << std::endl;
std::cout << "The arrangement is "
<< (valid ? "valid." : "NOT valid!") << std::endl;
if (! valid) return (1);
// Remove the edges.
for (size_t i = 0; i < hhs.size(); i++) {
arr.remove_edge(hhs[i]);
bool valid = arr.is_valid();
std::cout << " Removed " << i+1 << " curve(s), arrangement is "
<< (valid ? "valid." : "NOT valid!") << std::endl;
if (! valid) return (1);
}
std::cout << "Final arrangement size:"
<< " V = " << arr.number_of_vertices()
<< ", E = " << arr.number_of_edges()
<< ", F = " << arr.number_of_faces() << std::endl;
if (!::test(arr)) return 1;
/* Construct another arrangement of a segment connected to a ray.
* First remove the ray, then remove the segment.
*
* o---------------o
* | |
* | |
* | |
* | o--o----|
* | |
* | |
* | |
* o---------------o
*/
if (!test_ray(arr, arr.unbounded_face())) return 1;
/* Construct another arrangement of a segment connected to a ray.
* First remove the ray, then remove the segment.
*
* o---------------o
* | |
* | |
* | |
* | o--o----|
* | |
* o---------------o
* | |
* o---------------o
*/
Line_2 l1(Point_2(0, -1), Point_2(1, -1));
Halfedge_handle eh1 =
arr.insert_in_face_interior(X_monotone_curve_2(l1), arr.unbounded_face());
if (!test_ray(arr, eh1->face())) return 1;
arr.remove_edge(eh1);
/* Construct another arrangement of a segment connected to a ray.
* First remove the ray, then remove the segment.
*
* o-----o---------o
* | | |
* | | |
* | | |
* | | o--o----|
* | | |
* | | |
* | | |
* o-----o---------o
*/
Line_2 l2(Point_2(-1, 0), Point_2(-1, 1));
Halfedge_handle eh2 =
arr.insert_in_face_interior(X_monotone_curve_2(l2), arr.unbounded_face());
if (!test_ray(arr, eh2->twin()->face())) return 1;
arr.remove_edge(eh2);
return 0;
}