CGAL users discussion list

[Efraim Fogel <>]

You need to implement yourself the function that removes a hole using 
the remove_edge() method of the Arrangement_2 class. The function that 
you tried to use is private and internal, and does do what you may think 
it does.

Another option is to compute the union of the Polygon_set object with 
the holes you are trying to remove, not that efficient though....

Or, you can simply ignore the holes. Start with the unbounded face, and 
traverse its holes.

Keith Ealanta wrote:

> I'm trying to fill all the holes in a Polygon_set_2
> After initial struggles I'm now at least finding the faces that 
> describe the holes, but I can't seem to remove the holes from them.
>
> My code is as follows... (sorry for the weird indenting, I've set it 
> up to try to make it more readable in email)
>
> My typedefs are...
> typedef CGAL::Cartesian<double>                        Kernel;
> typedef Kernel::Point_2                                Point_2;
> typedef CGAL::Polygon_2<Kernel>                        Polygon_2;
> typedef CGAL::Polygon_with_holes_2<Kernel>      Polygon_with_holes_2;
> typedef CGAL::Polygon_set_2<Kernel>                    Polygon_set_2;
> typedef CGAL::Polygon_2<Kernel>::Vertex_const_iterator VertexIterator;
> typedef CGAL::Polygon_set_2<Kernel>::Arrangement_2     Arrangement_2;
>
> And here's the code at issue.
>
> bool Area::FillHollows()
> {
>   bool result = false;
>   Arrangement_2 arr=data->total_area.arrangement();
>        
>   Arrangement_2::Face_iterator fi;
>   std::cout << "Arrangement --------- ";
>   std::cout << arr.number_of_faces() << " faces." << std::endl;
>
>   for (fi=arr.faces_begin();fi!= arr.faces_end();fi++)
>   {
>     if (fi->is_unbounded())
>     {
>       continue; // ignore the outer border
>     }
>
>     std::cout << "### Face ###" << std::endl;
>
>     std::cout << "Border : " ;
>     print_ccb(fi->outer_ccb());
>     std::cout << std::endl;
>
>
>     std::cout << "Hole count : " << fi->number_of_holes() << std::endl;
>     std::cout << "---------" << std::endl;
>
>     Arrangement_2::Hole_iterator hi;
>     int cnter = 0;
>     for (hi = fi->holes_begin();hi!=fi->holes_end();hi++)
>     {
>       std::cout << "hole - " << ++cnter << " :   ";
>       print_ccb(*hi);
>
> // ################# Here's where I hit problems ##################
>       arr.non_const_handle(fi)->erase_hole(hi);
> // ################# Just that one line really. ###################
>       result = true;
>     }
>     std::cout << std::endl;
>   }
>   return result;
> }
>
> This gets the following compile error...
>
> .\CGAL_Access.cpp(132) : error C2664:
> 'CGAL::Arrangement_2<Traits_,Dcel_>::Face::erase_hole' :
>     cannot convert parameter 1 from
>         'CGAL::I_HalfedgeDS_iterator<I,Val,Dist,Ctg>' to
>         'CGAL::I_HalfedgeDS_iterator<I,Val,Dist,Ctg>'
>         with
> [ 
> Traits_=CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>, 
>
> Dcel_=CGAL::Gps_dcel<CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>> 
>
> ]
>         and
> [
> I=CGAL::I_HalfedgeDS_iterator<CGAL::Arr_face_base::Hole_iterator,CGAL::Arr_halfedge<CGAL::Arr_vertex_base<CGAL::Point_2<CGAL::Cartesian<double>>>,CGAL::Arr_halfedge_base<CGAL::Arr_segment_2<Kernel>>,CGAL::Gps_face> 
>
> *,__w64 int,std::list<void *>::_Iterator<false>::iterator_category>,
> Val=CGAL::_HalfedgeDS_facet_circ<CGAL::Arrangement_2<CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>,CGAL::Gps_dcel<CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>>>::Halfedge,CGAL::I_HalfedgeDS_iterator<CGAL::CGALi::In_place_list_iterator<CGAL::Arr_halfedge<CGAL::Arr_vertex_base<CGAL::Point_2<CGAL::Cartesian<double>>>,CGAL::Arr_halfedge_base<CGAL::Arr_segment_2<Kernel>>,CGAL::Gps_face>,std::allocator<CGAL::Arr_halfedge<CGAL::Arr_vertex_base<CGAL::Point_2<CGAL::Cartesian<double>>>,CGAL::Arr_halfedge_base<CGAL::Arr_segment_2<Kernel>>,CGAL::Gps_face>>>,CGAL::Arrangement_2<CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>,CGAL::Gps_dcel<CGAL::Gps_segment_traits_2<Kernel,std::vector<CGAL::Point_2<CGAL::Cartesian<double>>>>>>::Halfedge,__w64 
>
> int,std::bidirectional_iterator_tag>,CGAL::Bidirectional_circulator_tag>,
> Dist=__w64 int,
> Ctg=std::bidirectional_iterator_tag
> ]
>         and
> [
> I=CGAL::Arr_face_base::Hole_iterator,
>
> Val=CGAL::Arr_halfedge<CGAL::Arr_vertex_base<CGAL::Point_2<CGAL::Cartesian<double>>>,CGAL::Arr_halfedge_base<CGAL::Arr_segment_2<Kernel>>,CGAL::Gps_face> 
>
> *,
> Dist=__w64 int,
> Ctg=std::list<void *>::_Iterator<false>::iterator_category
> ]
> No user-defined-conversion operator available that can perform this 
> conversion, or the operator cannot be called.
>
> It looks to me as though erase_hole can't accept the hole_iterator it 
> is defined as using?
>
> Can anyone see what is wrong?
> Am I still doing something stupid?
>
> I've left all the cout statements in so I can show the sample data 
> being processed.
> The print_ccb is as per the pdf doco, but has had the curves output 
> part removed.
> The dataset is a triangle with a triangle missing from the middle of 
> it, and a separate freestanding triangle.
>
> Arrangement --------- 4 faces.
> ### Face ###
> Border : Is_on_hole = 0 : (300 250)(100 400)(100 100)(300 250)
> Hole count : 0
> ---------
>
> ### Face ###
> Border : Is_on_hole = 0 : (600 400)(500 350)(600 300)(600 400)
> Hole count : 0
> ---------
>
> ### Face ###
> Border : Is_on_hole = 0 : (900 350)(400 600)(400 100)(900 350)
> Hole count : 1
> ---------
> hole - 1 :   Is_on_hole = 1 : (500 350)(600 400)(600 300)(500 350)


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