CGAL users discussion list

[Andreas Fabri <>]

Hello,

I started to answer this mail and wanted to give links to follow
in order to find  Edge, cw, Face, Vertex.


> Agnel C J Kurian wrote:
> > How do I get x and y co-ordinates from a Finite_edges_iterator?
> >
> > struct K : CGAL::Exact_predicates_inexact_constructions_kernel {};
> >
> > typedef CGAL::Triangulation_vertex_base_2<K>            Vb;
> > typedef CGAL::Constrained_triangulation_face_base_2<K>        Fb;
> > typedef CGAL::Triangulation_data_structure_2<Vb,Fb>        TDS;
> > typedef CGAL::Exact_predicates_tag                Itag;
> > typedef CGAL::Constrained_triangulation_2<K, TDS, Itag>         CT;
> > typedef CT::Point                                                   
> > Point;
> >
> >     for (CT::Finite_edges_iterator eit = ct.finite_edges_begin();
> >         eit != ct.finite_edges_end(); ++eit){
> >         <b>// todo: list x and y co-ordinates here</b>
> >     }

Hello,

It is in the manual, but how to get there with a minimum of links to follow.


When you are in the reference manual page of the Triangulation_2 (which is 
base class of others)
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Triangulation_2_ref/Class_Triangulation_2.html

you see in the section "Types"

  "typedef Tds::Face         Face;          the face type. "

and in the section "Parameters"

  "By default, the triangulation data structure is instantiated by
   CGAL::Triangulation_data_structure_2 < 
CGAL::Triangulation_vertex_base_2<Gt>,
                                          CGAL::Triangulation_face_base_2<Gt> > >. 
"


To know more about Face click on   CGAL::Triangulation_face_base_2

In the section "Is Model for the Concepts"
you have to click on  "TriangulationFaceBase_2"

and there you have to click on

  "Refines

   TriangulationDSFaceBase_2"


and we now know that in a face I can access a vertex.



Without making things completely redudant I suggest to add  a shortcut from 
the
very first typedef to the very last page, because to explain this path of 
links
is correct and minimalistic (Occam's razor), but not user friendly.

andreas