[vtkusers] Design Gripes

[Murad Nayal]

Dear Dr. Martin

Thanks for the feedback. sorry I didn't notice previous discussions.
glad to know the user guide is up to date on vtk 4.0. Just ordered a
copy.

also for reasons of code clarity, I would advocate vtk use bool instead
of int for boolean variables. I wouldn't think there is a C++ compiler
that won't understand bool right now. I suppose backward compatibility
issues might also be a concern here.

another aspect that would be on my wish list in a perfect world would be
adoption of the STL in vtk.

regards

Ken Martin wrote:
> 
> I'll address only one issue here since the others have been beat on in
> the past. The void (*)(void *) stuff is all old style code left in for
> backwards compatibility. I would gladly yank it out but... then a
> bunch of people would (with good reason) scream that their code no
> longer works. The new style is to use the command observer design
> pattern which is implemented in vtkCommand.h. It supports callbacks
> with state etc. The examples in VTK/Exmaples/Tutorial/Step2 all show
> callbacks using the new observer style. The VTK 4.0 user guide also
> only discusses the new style of observer not the old style void (*)
> ...  Unfortunately leaving the old style code in for backwards
> compatibility can be confusing and misleading to new users. In an
> ideal world someone should modify the comments above the old style
> code to indicate that it is no longer the preferred way to do this.
> 
> Thanks
> Ken
> 
> > Vector3D class. Also, it would be really nice if call back functions
> > were function objects that can maintain state. programming
> > with function
> > pointers like void (*)(void*) and associated argument
> > delete functions
> > seems clunky at best. I know there are constraints related to the
> > underlying graphics libraries. but this still could be
> > implemented with
> > no more than an additional indirect function call overhead.
> > would that
> > be so bad for performance? etc..
> >
> > I found the book helpful in getting to know the mindset of the
> > designers. any plans to provide an updated edition for
> > vtk4? Are there
> > any other design documents that cover vtk4?
> >
> > best,
> >
> >
> > --
> > Murad Nayal M.D. Ph.D.
> > Department of Biochemistry and Molecular Biophysics
> > College of Physicians and Surgeons of Columbia University
> > 630 West 168th Street. New York, NY 10032
> > Tel: 212-305-6884     Fax: 212-305-6926
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-- 
Murad Nayal M.D. Ph.D.
Department of Biochemistry and Molecular Biophysics
College of Physicians and Surgeons of Columbia University
630 West 168th Street. New York, NY 10032
Tel: 212-305-6884	Fax: 212-305-6926