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hi all,
i would like to applicate voronoi with points. 

this part works fine by this code :
/////////////////////////////////////////////////////////////////
#include <CGAL/basic.h>

// standard includes
#include <iostream>
#include <fstream>
#include <cassert>

// includes for defining the Voronoi diagram adaptor
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Voronoi_diagram_2.h>
#include <CGAL/Delaunay_triangulation_adaptation_traits_2.h>
#include <CGAL/Delaunay_triangulation_adaptation_policies_2.h>

// typedefs for defining the adaptor
typedef CGAL::Exact_predicates_inexact_constructions_kernel                  
K;
typedef CGAL::Delaunay_triangulation_2<K>                                    
DT;
typedef CGAL::Delaunay_triangulation_adaptation_traits_2<DT>                 
AT;
typedef CGAL::Delaunay_triangulation_caching_degeneracy_removal_policy_2<DT> 
AP;
typedef CGAL::Voronoi_diagram_2<DT,AT,AP>                                    
VD;

// typedef for the result type of the point location
typedef AT::Site_2                    Site_2;
typedef AT::Point_2                   Point_2;

typedef VD::Locate_result             Locate_result;
typedef VD::Vertex_handle             Vertex_handle;
typedef VD::Face_handle               Face_handle;
typedef VD::Halfedge_handle           Halfedge_handle;
typedef VD::Ccb_halfedge_circulator   Ccb_halfedge_circulator;

void print_endpoint(Halfedge_handle e, bool is_src) {
  std::cout << "\t";
  if ( is_src ) {
    if ( e->has_source() )  std::cout << e->source()->point() << std::endl;
    else  std::cout << "point at infinity" << std::endl;
  } else {
    if ( e->has_target() )  std::cout << e->target()->point() << std::endl;
    else  std::cout << "point at infinity" << std::endl;
  }
}

int main()
{
        
  VD vd;
  VD::Face_iterator f;

  Point_2 *p;
        
  for(int i=0;i<10;i++)
  {
          p=new Point_2(rand()%200,rand()%200);
          vd.insert(*p);
          delete p;
          p=0;
  }

  Ccb_halfedge_circulator ec_start,ec;

  for(f=vd.faces_begin();f!=vd.faces_end();f++)
  {
          std::cout << "\n\n";
        ec_start = (*f).outer_ccb();
    ec = ec_start;
      do {
        print_endpoint(ec, false);
      } while ( ++ec != ec_start );

  }

  return 0;
}
/////////////////////////////////////////////////////////////////////////

My problem is :
faces in corners has Halfedges with points at infinity.
how can i give an extent to voronoi (for exemple a rectangle), then this 
faces can complete their Halfedges with points at infinity with intersection 
with the extent?

thank you for your help