[vtk-developers] Re: Distributing GL2PS as part of VTK.

[Christophe Geuzaine]

Prabhu Ramachandran wrote:
> Dear Christophe,
> 
> I recently added a vtkGL2PSExporter to VTK (http://www.vtk.org).  I
> have been thinking about adding GL2PS to the VTK sources so that VTK
> users would find it easy to build VTK with GL2PS support.  Currently
> they have to download GL2PS separately, build it and configure VTK to
> use GL2PS.  Its not too hard to do but is a bit of a pain considering
> that VTK is a huge build with many different options.  So its easy to
> forget about or ignore GL2PS.  Admittedly, users who *really* want
> GL2PS support will get it working.  However, not all users build VTK
> by hand.  For example Debian users are likely to use Debian's packages
> which do not support GL2PS.
> 
> Anyway, the issue with including GL2PS inside VTK is the license.  VTK
> is distributed under a BSD-like license.  If we include GL2PS as part
> of VTK we will add a readme to the GL2PS directory warning users that
> GL2PS is LGPL'd and any modifications to it are subject to the LGPL.
> However, is it even legal to distribute sources and binaries of VTK
> along with GL2PS?  Please note that we will include GL2PS as part of
> VTK only to ease the compilation procedure and will not make any
> modifications to GL2PS itself.
> 
> I'd like to have your views on the subject.  Do you think it is legal
> to distribute GL2PS as part of VTK?  Would you approve of such usage?
> If its illegal and you do approve of our usage would it be possible to
> provide an exception for our use?
> 

Guys - I don't plan to release GL2PS under a BSD-like license, but I
would have no problem adding an exception to the LGPL to allow for
static linking. This would allow VTK users to develop completely
closed-source software including GL2PS, provided that GL2PS is not modified.

This is the fair (IMHO) compromise adopted by the FLTK folks
(http://www.fltk.org), which permits to use the library the way you want
(even for proprietary projects) but still requires people to contribute
their changes if they want to distribute code based on *modified* versions.

Tell me what you think...

Cheers,

Christophe

-- 
Christophe A. Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org