[Insight-developers] Re: [Insight-users] new VTK 4.0 compatible version of vtkFlRenderWindowInteractor

[David.Pont@ForestResearch.co.nz]

Hi everyone,
    Charl, thanks for the update, I had heard of ITK but am not on its
mailing lists. I am no expert on licensing..., and I am happy to see the
class being used for ITK.

Here are a few thoughts:



Changes to vtkFlRenderWindowInteractor

- For one application I extended vtkFlRenderWindowInteractor to support a
user registered callback for interaction events (mouse, keyboard). This was
to display current cursor position in world coords on a status line, and to
call application logic on "special" key presses. There may be a way to do
this with vtkInteractorStyle? but it was quick and effective for me. So
this could be a suggested extension to the class.

- Extract the core structure as a generic base class for linking windowing
libraries with vtk, vtkFlRenderWindowInteractor would be a specific
descendant.



vtkFlRenderWindowInteractor distribution with ITK

- Can the class be contributed to vtk? I know this introduces a dependancy
on an external library (FLTK) with possible issues around distributing,
building and supporting the vtk distribution. Can it be an optional extra
that is included in the distribution (and testing?) but excluded from the
usual distribution build? This would save ITKers and other vtk-FLTKers from
having to download one more piece to get set up.



  regards

     Dave Pont




                                                                                                     
                    "Charl P. Botha"                                                                 
                    <c.p.botha@its.tudelf       To:     insight-users@public.kitware.com,            
                    t.nl>                        insight-developers@public.kitware.com               
                    Sent by: "Charl P.          cc:     david.pont@forestresearch.co.nz              
                    Botha"                      Subject:     Re: [Insight-users] new VTK 4.0         
                    <cpbotha@duticg.twi.t        compatible version of vtkFlRenderWindowInteractor   
                    udelft.nl>                                                                       
                                                                                                     
                                                                                                     
                    19/03/2002 21:09                                                                 
                                                                                                     
                                                                                                     




Dear ITKers and Luis,

I am quoting most of the previous mail so that David Pont, on whom's code
and concept vtkFlRenderWindowInteractor is based, also knows what's being
discussed.

On Mon, Mar 18, 2002 at 05:24:27PM -0500, Luis Ibanez wrote:
> That's great news, thank you  for letting us know.
> We have found this class very useful.
>
> BTW we were wondering about the conditions under
> we could keep your vtkFlRenderWindowInteractor
> class in the ITK distribution. So far we have copied it
> in every Example that requires to use VTK and FLTK
> keeping the header copyright intact.
>
> We could ask users to directly download it from your
> page in the same way we ask to dowload FLTK or
> VTK for those examples that need it.  The advantage of
> the direct download is that they will always get the latest
> version.
>
> What would you think it is the right way to proceed in
> this case ?

vtkFlRenderWindowInteractor, being as simple and single-minded as it is, is
just about done and there probably won't be all that many releases in the
future, unless VTK changes drastically.  I would think it more convenient
to
include the latest version in ITK.  However, and I'm no expert on this, the
fact that it's under the LGPL might pose problems.  In short, one is
allowed
to link binary applications with it, but if one distributes these,
vtkFlRenderWindowInteractor itself must be made available in source form.
Also, modifications _directly_ to LGPL'd source must also be LGPL.

There might be experts on the ITK list who can comment on this.  If the
LGPL
is going to pose problems, maybe we could dual-license the code.  I'm
hoping
that it can be integrated without problems.

Best regards,
Charl

>
> Thanks
>
> Luis
>
> =====================================
> Charl P. Botha wrote:
>
> >Dear ITKers,
> >
> >I attempted building the ITK examples today and experienced some
> >vtkFlRenderWindowInteractor + VTK 4.0 related errors in
Examples/FEMMesh/
> >code.  Fortunately, the vtkFlRWI code is mine.
> >
> >This is to announce that version 0.5 of this class is available from
> >http://cpbotha.net/vtkFlRenderWindowInteractor.html with the major
change
> >that it now builds and works with VTK 3.2 and VTK 4.0.  Feel free to
update
> >the version you have in the FEMMesh example.  The code is under the LGPL
> >license.
> >
> >Regards,
> >Charl
> >
> >PS. I'm not subscribed to this list.
> >
>
>
>

--
charl p. botha http://cpbotha.net/ http://visualisation.tudelft.nl/