[vtk-developers] Virtual methods in VTK classes

[Will Schroeder]

Hi Charl-

At 01:44 PM 7/1/2003 +0200, Charl P. Botha wrote:

>The 3D widgets are in my list of "most useful VTK, err, widgets", but
>probably because I spend a lot of time with interaction problems.
>AFAIK, you were the major force behind this.  Thanks!!

This is really a good example of collaboration. Bill Hoffman and Ken Martin 
came up with a really nifty design for the command/observer event handling 
that allowed prioritizing events and aborting the processing of events. 
Dean, Ken and some other folks have been adding some cool widgets, plus 
I've had ideas for several more from Bill L. If I had the time I'd enjoy 
implementing another half dozen or so widgets.... I think that we've barely 
scratched the surface of what can be done.


>BTW, whilst playing with this, I noticed that HandleOn() and HandleOff()
>have never been implemented.  They're declared in the class, but because
>they weren't virtual, the compiler doesn't complain.  Do you have this
>code lying around perhaps?  If not, I'll think something up.

The HandlesOn() and HandlesOff() methods look like an implementation 
experiment that didn't pan out. I'd just eliminate them unless you can 
think of something better. (It could be that before the HandleProperty was 
added---which can be used with zero opacity to effectively turn the handles 
off---the idea was to have an ivar to do this.)

Will