CGAL users discussion list

[Guillaume Damiand <>]

Hi Hermann;

Sorry for the late reply.


Le 31/07/2024 à 00:14,  a écrit :
> I started using CGAL after having learned about its "width of 
> pointset" implementation.
> I created an issue on what I found:
> https://github.com/CGAL/cgal/issues/8358
>
> Then I learned more and more about CGAL, and really love its 
> Basic_viewer with
> 24 key and 33 mouse controls described when hitting "h".
>
> For my lattice sphere work I used draw_polyhedron.cpp example a lot.
> Now I am working on planar graphs, and found that it can be used for 
> that as well.
> When I create a planar straight line drawing with Boost
> https://github.com/Hermann-SW/random_maximal_planar_embedding/tree/main/boost#random_maximal_planar_embedding 
>
> z=0 is written for all 2D point coordinates in the created .off file.


I am happy that you found helpful the cgal basic viewer ;)

> That works well, but with small problems:
> 1) starts in mono mode
> 2) does not allow to rotate because all points in same plane
> 3) inverse_normal is true and cannot be changed
>
> I found workaround for what I want, for Qt5 as well as Qt6:
> https://github.com/Hermann-SW/random_maximal_planar_embedding/tree/main/boost/cgal#build 


I was not able to test your code, it seems draw_planar.hpp is missing in 
your git repository.
In 7c.mp.off, there is one big triangle that overlap all the other 
triangles, explaining why you think the drawing is in mono color.

> 1) starts in color mode by patches to local CGAL file copies
> 3) starts with inverse_normal false which makes the face colors brighter
>
> This only works with colored faces (visit repo link above) if I set 
> z=-1 for first point coordinate. Otherwise graph is drawn in mono mode.
>
> My question is, whether CGAL Basic_viewer can display planar graphs like
> draw_planar.cpp does, without my patches somehow ?

Many updates were done in the basic viewer, you can get the last version 
in the cgal master branch (and more updates are coming).

Now you can use the class  QApplication_and_basic_viewer and modify the 
initial parameters of the basic viewer before to run the viewer.

I think this can solve your needs (maybe some setters are missing).
Please test and give me some feedback.

Note also that the 2D mode can be switched using the O key.

Best regards
Guillaume



> Regards,
>
> Hermann Stamm-Wilbrandt.


--
===================================================================
Guillaume DAMIAND

CNRS - LIRIS UMR 5205
Université Claude Bernard
Bâtiment Nautibus (710)
Bureau 12.047
23-25 avenue Pierre de Coubertin
69622 Villeurbanne Cedex (France)
-------------------------------------------------------------------
Tél: +33 (0)4 72 43 26 10                 Fax: +33 (0)4 72 43 15 36
Mail: 
Web: http://liris.cnrs.fr/guillaume.damiand/
===================================================================