CGAL users discussion list

[Yoann LE BARS <>]

Hello everybody out there!

        Well, I have yet another problem. Thanks to Chris Marsh (thread from
October 8th to October 9th on this mailing list), I have been able to
load a 2D mesh with CGAL, actually making it a 3D mesh with z component
set to 0. Now, I need to plot it and as the code I am working on use Qt
(version 5), I try to use “CGAL::Qt::TriangulationGraphicsItem”.

        Here are the definitions I use:

/// \brief Allows for using 2D algorithms on the 3D points.
typedef CGAL::Projection_traits_xy_3<K> Gt;
/// \brief Vertex class.
typedef CGAL::Triangulation_vertex_base_2<Gt> Vb;
/// \brief Custom face class, use default face and vertex as required.
typedef CGAL::Constrained_triangulation_face_base_2<Gt> Fb;
/// \brief Type for 2D triangulation with CGAL.
typedef CGAL::Triangulation_data_structure_2<Vb, Fb> Triangulation;

        I try to create a “TriangulationGraphicsItem”:

p = new CGAL::Qt::TriangulationGraphicsItem<Triangulation> (mesh);

        The “mesh” object being an instantiation of “Triangulation”.

        But I obtain this error while compiling:

/usr/include/CGAL/Qt/TriangulationGraphicsItem.h:44:35: error: no type
named ‘Geom_traits’ in ‘class
CGAL::Triangulation_data_structure_2<CGAL::Triangulation_vertex_base_2<CGAL::Projection_traits_xy_3<CGAL::Epick>
>,
CGAL::Constrained_triangulation_face_base_2<CGAL::Projection_traits_xy_3<CGAL::Epick>
> >’

        So it turned out the classes I use do not have a “Geom_traits” type. 
In
a way or another, I need to provide this type. I cannot find more clue
on the documentation: maybe should I use some other classes? Does anyone
have some documentation for drawing with CGAL and Qt5, beside the
following, which did not gave me enough information to solve my problem?

https://doc.cgal.org/latest/GraphicsView/index.html

        Best regards.

-- 
Yoann LE BARS
http://le-bars.net/yoann
*Diaspora :