CGAL users discussion list

[Mariette Yvinec <>]

The solution of Michael won't  work if the polygonal regions
you are tracking are not simply connected and convex.

Here is a more general  solution.
Starting from the examples that mark the triangular faces inside the polgon
it is easy to get the edges inside the polygons:
these are the edges adjacent to two marked polygons.

Mariette

Le 29/09/13 08:45, Michael Hoffmann a écrit :

If you label the vertices of your constrained polygons by component/polygon (i.e., the first by 1, the second by 2, etc.), you can just iterate over the edges of the triangulation and select those whose endpoints have the same label.

It sounds like you know those polygons because they are part of your input. If not, you might have to compute them via BFS/DFS or so.
For the labels you can use the vertex_with_info classes.

hth, Michael

-- 
Mariette Yvinec
Geometrica project team
INRIA  Sophia-Antipolis