CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

annie wrote:
> Hello, 
> I'm stuck with trying to get vertices of segment Delaunay graph. I was 
> trying to iterate through the non-infinite edges of the segment 
> Delaunay graph as in the sample in CGAL, trying this inside the loop: 
> SDG2::Edge e = *eit; 
> cout<<*( e.first->vertex( sdg.ccw(e.second) )); 
> cout<<*( e.first->vertex( sdg.cw(e.second) )); 
> The code gives nothing as result, only segments that points belong to 
> are written if I also use ->site() method. But I'm interested in 
> endpoints of edges ... 
> I get similar result using Finite_vertices_iterator. 
> Did anyone try to get these vertices? Please, I would be very grateful 
> for help...

I don't know this package very well, but looking at the code
of the draw_dual function you have:

  template< class Stream >
  Stream& draw_dual_edge(Edge e, Stream& str) const
  {
    CGAL_precondition( !is_infinite(e) );
    typename Geom_traits::Line_2              l;
    typename Geom_traits::Segment_2           s;
    typename Geom_traits::Ray_2               r;
    CGAL::Parabola_segment_2<Gt>              ps;

    CGAL::Object o = CGAL::primal(e);

    if (CGAL::assign(l, o))   str << l;
    if (CGAL::assign(s, o))   str << s;
    if (CGAL::assign(r, o))   str << r;
    if (CGAL::assign(ps, o))  ps.draw(str);

    return str;
  }

primal and Parabola_segment_2 are not documented but while people 
knowing a documented answer, it may help.


S.