Re: [Paraview] qvtk problems with the pipeline
Dominik Szczerba <dominik <at> itis.ethz.ch>
2009-08-01 17:52:45 GMT
Clinton Stimpson wrote:
> On 08/01/2009 05:01 AM, Dominik Szczerba wrote:
>> 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?
> vtkSetMacro checks for changes before calling this->Modified(); But are
> you saying its a problem because not all Set functions check for changes?
I am saying that (e.g.) setting VOI in vtkExtractVOI or
InputArrayToProcess in vtkThreshold to the already previously set values
(no factual change, just re-feed of the old ones) triggers the pipeline
to re-execute. I do not understand this behavior as I was - as you point
out - hoping for the set macros to take care of that.
> To do your own bookkeeping, one idea is to connect to the QWidget's user
> property's notify signal (see QMetaObject::userPropery), and anytime one
> of those fires, you add to a list of widgets that have changed. Then at
> apply time, just push those values down.
A little above my knowledge level but many thanks for the pointers to
Overall, many thanks for valuable insights.
d o m i n i k s z c z e r b a , p h d . . . . . . . . . . .
c o m p u t a t i o n a l l i f e s c i e n c e g r o u p
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