[vtkusers] [Paraview] qvtk problems with the pipeline

[Dominik Szczerba]

Many thanks for the feedback. Pls see below:

Clinton Stimpson wrote:
> Dominik Szczerba wrote:
>> My pipeline works all right and gets updated on demand properly. I 
>> achieve it by connecting spinboxes/lineedits etc. to functions that 
>> set parameters of my filters before I explicitly hit the final 'apply' 
>> button. The annoying problem is that the pipeline gets executed also 
>> when I interact with the render window (click to rotate etc.). I did 
>> not (intend to) set up such functionality, I want the pipeline to 
>> execute only after an explicit button click (like in paraview). How do 
>> I find out who is triggering the pipeline behind my back?
>>
>> - Dominik
>>
> ParaView queues up the changes, and only applies them to the filters 
> when the apply button is pressed.
> If you're applying them on the filters when spinboxes/lineedits change, 
> and a menu comes and goes over the graphics view, that could trigger an 
> update you might not want.
> 
> How about your apply button gathering the parameters from the widgets on 
> the form and applying them?

That was my original idea and implementation: However, this way the 
WHOLE pipeline ALWAYS gets re-executed. Concrete example pipeline: 
extractVOI->GaussianSmooth. If Apply button gathers the parameters and 
sets them to the filters every time, changing e.g. only smoothing params 
(while keeping the same VOI) still causes both filters to re-execute. 
This should not happen, as VOI should be up to date. The same is true 
for more filters, e.g. Threshold: re-feeding the same parameters and/or 
arrays to process somehow fools the up-to-date'ness of the filter. Am I 
expected to walk around the problem by bookkeeping the changing params 
and the up-to-date'ness myself?

Note that this is different to paraview, where you have only one filter 
per menu entry and can explicitly request changes. Here I have one 
meta-filter, consisting of several atomic ones.

After your remark I feel the original approach was the right one. But 
then how do I only request the update if a REAL CHANGE and not only a 
FORMAL SET of parameters is the case?

regards,
Dominik

> 
> Clint
> 


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