CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On vendredi 04 novembre 2011 16:23:06 RossH wrote:
> I'm currently working on drawing walks on Triangulations using Qt and CGAL.
> This involves drawing a triangulation and then redrawing certain triangles
> in different colours to show that they have been visited.
> 
> An older version of the CGAL manual seems to describe a procedure for doing
> this using* Qt_widget *:
> 
> (
> http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/Qt_widget/Chapter_main.
> html
> http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/Qt_widget/Chapter_main
> .html ).

CGAL Qt_widget was a library using Qt3. Qt3 is deprecated by Qt4 for a long 
time, and the CGAL project decided to deprecate CGAL Qt_widget as well.

> However this seems to differ from the descriptions given in the newer
> manual:
> 
> (
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/GraphicsView/Chapter
> _main.html
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/GraphicsView/Chapte
> r_main.html )
> 
> Which is based on *QGraphicsView*.

That uses Qt4 QGraphicsView.

> So my question is: Is Qt_widget depreciated? If yes, then is there a "nice"
> way to redraw individual triangles from a TriangulationGraphicsItem?

You can use QGraphicsView directly by adding some QGraphicsPolygonItem 
yourself to the scene. You can even mix that with a display of a 
CGAL::TriangulationGraphicsItem.

See:
  http://doc.qt.nokia.com/latest/graphicsview.html
  http://doc.qt.nokia.com/latest/qgraphicspolygonitem.html

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/