CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

IIUC what you want, you want to get the edge opposite to the infinite 
vertex.

Something like the following should work:

DT::Face_handle fh = XXX;
DT::Vertex_handle v_inf = dt.infinite_vertex();
DT::Edge opp_edge(fh, fh->index(v_inf));

Sebastien.


On 08/23/2018 11:46 AM, brainslush wrote:
> I have a convex polygon or a convex hull as input data for a Delaunay
> triangulation and want to get the voronoi circle center or ray for the
> convex hull edges.
> I know that I can get the rays of the hull using
>
>      auto eit = hullDt.edges_begin();
>      for ( ; eit !=hullDt.edges_end(); ++eit) {
>          CGAL::Object o = hullDt.dual(eit);
>          if (auto _el = CGAL::object_cast<K::Ray_2>(&o)) {
>              // do some magic
>          }
>      }
>
> but this approach returns them unordered and the corresponding hull segment
> (eit) in "arbitrary" directions as we are visiting not the infinite face but
> the one adjacent and inside the polygon to it.
>
> So I thought I could use the circulator
>
>      hullDt.incident_faces(hullDt.infinite_vertex());
>
> and determine the adjacent face inside the hull or the inside edge of the
> hull segment which I then pass to
>
>      hullDt.dual(insideFace);
>
> which then should give me what I want, right?
> The only thing I don't know how I find the adjacent face/edge. I probably
> would find it eventually but maybe someone more familiar with the code knows
> the right functions.
>
> Thanks
>
>
>
> --
> Sent from: http://cgal-discuss.949826.n4.nabble.com/