CGAL users discussion list

[Hanjoerg Seybold <>]

Hello!
I am making calculations with voronoi diagrams. For my application i have to 
intersect the unbounded edges/halfedges with a boundary given by a polygon 
or a segment or line. After studying the manual and i am a bit confused 
about the halfedge structure. 

1. it is said that "Halfedges are oriented edges", but i cannot find a
  method how to access  the orientation. 

2. It is possibe to check if a halfedge IS a segment or ray. h.is_ray(),
  but if the halfedge IS a ray, how can i access its features (direction,
  etc.)?
3. My Problem is that i iterate through the halfedges and i want to know if
  a infinite halfedge intersects a polygon. For this i wanted to construct
  a  line ray etc out of the halfedge, but i dont know how to obtain the
  direction in the case that the halfedge has only source OR target. 

Any help would be welcome 

  hansjoerg