CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

That's a bit tricky but since the arrangement is non-const,
the simplex type are the non-const one.

>          Arrangement_2::Vertex_handle    vertex;
>          Arrangement_2::Halfedge_handle  edge;
>          Arrangement_2::Face_handle      face;

Sebastien.

On 11/19/2015 06:50 PM, DamienDous wrote:
> Hi All,
>
> I try to use zone(arrangement, segment, back_inserter(intersected_objs))
> funtion. Here is my code :
>
> /* some includes */
>
> typedef CGAL::Simple_cartesian<double> Kernel;
> typedef CGAL::Arr_segment_traits_2<Kernel>        Traits_2;
> typedef CGAL::Arr_face_extended_dcel<Traits_2, unsigned int> Dcel;
> typedef CGAL::Arrangement_2<Traits_2, Dcel> Arrangement_2;
>
> int            main()
> {
>          /* Create arrangement */
>          CGAL::Arrangement_2<Traits_2, Dcel>  arrangement;
>          insert(arrangement, Segment_2(Point_2(0, 0), Point_2(2, 0)));
>          insert(arrangement, Segment_2(Point_2(2, 0), Point_2(2, 2)));
>          insert(arrangement, Segment_2(Point_2(2, 2), Point_2(0, 2)));
>          insert(arrangement, Segment_2(Point_2(0, 2), Point_2(0, 0)));
>
>          /* Create segment */
>          const size_t segmentNumber = 3;
>          Segment_2 segments[segmentNumber];
>          segments[0] = Segment_2(Point_2(-2, -2), Point_2(-1, -1));
>          segments[1] = Segment_2(Point_2(-1, 1), Point_2(1, 1));
>          segments[2] = Segment_2(Point_2(0, 0), Point_2(3, 0));
>
>          /* Create structure to cast the objects given by zone function */
>          Arrangement_2::Vertex_const_handle    vertex;
>          Arrangement_2::Halfedge_const_handle  edge;
>          Arrangement_2::Face_const_handle      face;
>
>          /* Test for each segment which objects it will cross */
>          for (size_t k = 0; k < segmentNumber; k++)
>          {
>                  std::vector<CGAL::Object> intersected_objs;
>                  CGAL::zone(arrangement, segments[k],
> std::back_inserter(intersected_objs));
>
>                  std::cout << "the segment intersects " <<
> intersected_objs.size()
>                  << " objects" << std::endl;
>
>                  for (size_t i = 0; i < intersected_objs.size(); i++) {
>                          if (CGAL::assign(face, intersected_objs.at(i)))
>                          {
>                                  // segments[k] is located inside a face:
>                                  if (face->is_unbounded())
>                                          std::cout << "inside the unbounded
> face." << std::endl;
>                                  else
>                                          std::cout << "inside a bounded
> face." << std::endl;
>                          }
>                          else if (CGAL::assign(edge, intersected_objs.at(i)))
>                          {
>                                  // segments[k] is located on an edge:
>                                  std::cout << "on an edge: " << edge->curve()
> << std::endl;
>                          }
>                          else if (CGAL::assign(vertex,
> intersected_objs.at(i)))
>                          {
>                                  // segments[k] is located on a vertex:
>                                  if (vertex->is_isolated())
>                                          std::cout << "on an isolated vertex:
> " << vertex->point() << std::endl;
>                                  else
>                                          std::cout << "on a vertex: " <<
> vertex->point() << std::endl;
>                          }
>                          else
>                          {
>                                  std::cout << "invalid object " << std::endl;
>                          }
>                  }
>          }
> }
>
> Right now I assume the return of zone function could be
> Arrangement_2::Vertex_const_handle, Halfedge_const_handle,
> Face_const_handle. I do get non-empty intersected object list (and the
> number of intersected objects is correct), but when I try to object_cast its
> elements to Vertex/Halfedge/Face, I only get NULL pointer values. The
> documentation of zone() doesn't give a list of possible return type. What is
> the right way to use this function?
>
> Thanks a lot,
>
> Damien
>
>
>
> --
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> http://cgal-discuss.949826.n4.nabble.com/use-zone-with-Arrangement-2-tp4661363.html
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