CGAL - get Edge from Segment_2

Question

I am using CGAL and I have a Polygon that I created with some vertices.

Now I get a segment, with:

Segment_2 segment = polygon.edge(i)

where i is an index from 0 to polygon.size().

How can I transform an Segment_2 to an Edge? Like there is a t.segment(Edge e) to get a Segment_2 from an Edge, I want something to get the reverse (Segment_2 to Edge).

Now I am completely sure that this segment belongs to an Edge on the Triangulation_2, how can I get it? something like triangulation.edge(Segment_2) maybe.

Help please.

Answer 1

If you have kept the two vertex handles corresponding to the two points of the segment, you can use this function:

bool 
CGAL::Triangulation_2< Traits, Tds >::
is_edge(Vertex_handle va,
        Vertex_handle vb,
        Face_handle & fr,
        int & i
)

Assuming v1 and v2 are the vertex handles, and t your triangulation object:

Face_handle fh;
int i;
if(t.is_edge(v1, v2, fh, i)) {
  Edge my_edge = Edge(fh, i);
  // ... use your Edge
}