[IGSTK-Developers] Coordinate System questions

[Kevin Gary]

Hi Matt,

My student is working on the scene graph visualization tool. We are trying to 
introduce a central "manager" singleton that is aware of each time a 
child-parent relationship is constructed (or destructed) in the graph, and 
trying to do so without having to change existing IGSTK code. To us, the best 
way to do that is to observe a CoordinateSystem for events indicating when 
"RequestSetTransformAndParent" or "RequestDetachFromParent" have been called.

This would seem simple, but we have spent a while tracing through all the 
various macros and the CoordinateSystemDelegator (why does this exist?) and have 
a couple of questions -

1. Should we even try to observe a CoordinateSystem directly or its Delegator?
2. Why doesn't the Delegator use 
igstkCoordinateSystemClassInterfaceConstructorMacro() like the 4 object types 
that have Coordinate Systems?
3. It appears the Delegator observes itself? We admit some confusion as to why 
there is the ObserverCallback with a self reference that moves an event along.

But basically, our main question is to whether to insert a line at the end of 
CoordinateSystem::SetTransformAndParent to generate an event (it doesn't now), 
or whether to add it to the delegator somewhere in the midst of all the 
AddObserver stuff?

Thanks,
K2




-- 
===
Kevin A. Gary, Ph.D.
Assistant Professor
Division of Computing Studies
College of Technology and Innovation
Arizona State University at the Polytechnic Campus
(480)727-1373
http://dcs.asu.edu/faculty/KevinGary
kgary at asu.edu
-------------- next part --------------
A non-text attachment was scrubbed...
Name: kgary.vcf
Type: text/x-vcard
Size: 135 bytes
Desc: not available
URL: <http://public.kitware.com/pipermail/igstk-developers/attachments/20081010/5998a13a/attachment-0002.vcf>