[Paraview-developers] Where does the vtkSelection come from?

[Cornelis Bockemühl]

Thanks Utkarsh,

It looks like these were the final hints that made it happen for me!

First the "hints" entry really did the "magic" I was looking for.

And second I am using now a vtkPVSelectExtraction filter (inside my own
filter) for converting all the different types of selection into all cell
indices for easy further processing.

Overall I am getting the impression that these "Hints" are covering still a
lot more "magic" that is worth discovering... ;-)

Regards,
Cornelis


2017-01-17 23:03 GMT+01:00 Utkarsh Ayachit <utkarsh.ayachit at kitware.com>:

> The vtkSelection comes from a "Selection Source" proxy that ParaView
> internally creates that defines the selection. sources.xml [1] defines
> several types of selection sources, e.g. ThresholdSelectionSource,
> IDSelectionSource, SelectionQuerySource.
>
> To make your filter behave like the "Extract Selection" filter where
> it automatically sets up the selection, make sure you have the
> <SelectionInput> hint [2].
>
> Utkarsh
>
> [1] https://gitlab.kitware.com/paraview/paraview/blob/master/
> ParaViewCore/ServerManager/SMApplication/Resources/sources.xml#L1590-1904
> [2] https://gitlab.kitware.com/paraview/paraview/blob/master/
> ParaViewCore/ServerManager/SMApplication/Resources/
> filters.xml#L11911-11916
>
> On Tue, Jan 17, 2017 at 11:45 AM, Cornelis Bockemühl
> <cornelis.bockemuehl at gmail.com> wrote:
> > All day I am already struggling now with some possibly very "simple"
> > problem: I am trying to write a filter that applies some operations only
> to
> > selected cells of an "unstructured grid".
> >
> > I am taking the "extract selection" filter as an example. This filter
> takes
> > the "data" stuff at input port 0 and a vtkSelection object at input port
> 1,
> > then does the proper processing. However, from a user perspective the
> filter
> > is attached to one single input data set with selections. Like exactly
> the
> > unstructured grid with some cells selected: I can easily extract them
> with
> > the "extract selection" filter - and I do not have to specify a second
> data
> > item for input port 1!
> >
> > But if I am simulating exactly the code in the server XML (specifying two
> > input ports, for "input" and "selection"), then copying all the relevant
> > stuff from the cxx files of vtkPVExtractSelection.cxx,
> > vtkExtractSelection.cxx and vtkExtractSelecitonBase.cxx - I do not get
> the
> > same behaviour!
> >
> > Instead I am getting exactly what I would have expected otherwise: my
> filter
> > asks for a second input data item - but what should I choose? And then it
> > stops because indeed it does not find any vtkSelection data object at
> port
> > 1.
> >
> > While the latter looks somehow logical to me I still wonder how the
> extract
> > seleciton filter does the apparent "magic" of having that selection
> object
> > at port 1 for further processing!
> >
> > Any hint where I should have a look into the code, or what else I might
> have
> > forgotten?
> >
> > As I said I simulated the server XML and the cxx code, but now I guess
> that
> > maybe there are still other places in the code where I should have a
> look??
> >
> > Thanks in advance for any helpful hints!
> > Cornelis
> >
> > --
> > Cornelis Bockemühl
> > Basel, Schweiz
> >
> > _______________________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Search the list archives at:
> > http://markmail.org/search/?q=Paraview-developers
> >
> > Follow this link to subscribe/unsubscribe:
> > http://public.kitware.com/mailman/listinfo/paraview-developers
> >
>



-- 
Cornelis Bockemühl
Basel, Schweiz
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/paraview-developers/attachments/20170118/654a5527/attachment-0001.html>