CGAL users discussion list

[Yajie Yan <>]

Hi Efi,

Thanks for getting back with this useful information.

Another question: when using zone(arr, s, back_inserter(isected_objs)
) to compute the intersected objects between a segment s and
arrangement_2 arr, what are the possible objects in the output
isected_objs? Right now I assume the return could be
Arrangement_2::Vertex, Halfedge, Face. I do get non-empty
isected_objs, but when I try to object_cast its elements to
Vertex/Halfedge/Face, I only get NULL pointer values. The
documentation of zone() doesn't give a list of possible return type,
as doc of intersection() has done.

Thanks!
Yajie.

On 7/13/14, Efi Fogel 
<>
 wrote:
> There is a small typo in the CGAL 2D Arrangement code.
> The next version of CGAL will include the fix.
> If you want to fix it right away, you can apply the attached patch.
> Thanks for the report!
>
> On Fri, Jul 11, 2014 at 6:43 AM, Yajie Yan 
> <>
> wrote:
>
>> Hi All,
>>
>> I wonder if one could use do_intersect() & zone(), these two free
>> functions with an Arrangement_with_history_2 object. When I tried to
>> test do_intersect() with arr_with_hist I get this compile error:
>>
>> error C2039: 'traits' : is not a member of
>> 'CGAL::Arrangement_on_surface_2<GeomTraits_,TopTraits_>'
>>
>> D:\codes\libs\CGAL-4.4\include\CGAL\Arrangement_2\Arrangement_on_surface_2_global.h
>> 1522 1 curve_history
>>
>> I simply added 3 lines of code to the
>> Arrangement_on_surface_2_example/curve_history.cpp file:
>>
>> typedef CGAL::Arr_walk_along_line_point_location<Arr_with_hist_2>
>> Walk_pl;
>> Walk_pl pl1(arr);
>> std::cout << "intersect? " << do_intersect(arr, Segment_2(Point_2(3,
>> 2), Point_2(5, 3)), pl1) << std::endl;
>>
>> This addition works with the incremental_insertion example. So my
>> guess is maybe it's not possible to use this function with
>> arr_with_hist? If I'm wrong, what is the right way to do it?
>>
>>
>> Thanks a lot!
>> Yajie.
>>
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