[Paraview] Troubles with exporting selection labels from current ParaView render view

[Nenad Vujicic]

Utkarsh,

Thank you very much for answers about creating and initializing
DataLabelRepresentation. Now my source plugin works perfectly.

But, my exporting plugin (my first message) is still unable to export
labels which I get when try selecting several points. Here is what I
do:

1. Create Sphere and apply Elevation filter on it (I turn OFF 3d widget),
2. I select several points and in Selection Manager I select Elevation
for Point Labels,
3. In following code snippet I get only 2 message boxes (one of Sphere
and one for Elevation - both GeometryRepresentation),, but, there is
no DataLabelRepresentation.
4. I know how to extract labels parameters at this level (Selection*
parameters from representation), but not set of points over which are
generated labels,

// for all sources
for(i = 0; i < sources.size(); i++)
{
    // get source
    pqPipelineSource* source = sources.at(i);

    // for every source's output port, process it
    for(output_port = 0; output_port <
source->getNumberOfOutputPorts(); output_port++)
    {
        // traverse all representations
        for(j = 0; j < source->getRepresentations(output_port,
active_view).count(); j++)
        {
              QMessageBox::about(NULL, "",
GetCurrentSourceRepresentationSMName());
        }
    }
}

Should I try to catch
pqSelectionManager::selectionChanged(pqOutputPort*) to get data
structure over which are points which I can compare with data
structures extracted from vtkRenderWindow to generate labels?

Thanks for help in advance!

Nenad.

On Mon, May 18, 2015 at 3:49 PM, Utkarsh Ayachit
<utkarsh.ayachit at kitware.com> wrote:
>>     - Strange 1: I don't have anymore instance in
>> DataLabelRepresentation for Elevation pipeline source (btw, during
>> this traversing I get only one actor),
>
> I don't follow. DataLableRepresentation is indeed created for every
> representation shown in the render view.
>
>
>>     - Strange 2: When I traverse vtkRenderer's actors, I get 2 actors
>> (sphere mesh and actor with selected points), but, I'm unable to
>> connect selection label properties (which are tied with Elevation
>> pipeline source actor - sphere mesh) and mesh with selected points /
>> cells.
>
> Remember that label actors are added to the 2D / non-composited
> renderer, not the same as the 3D renderer. Which renderer are you
> looking at?
>
>> Q1: How to identify actor from vtkRenderer which contains selection
>> points / cells and get selection properties from this actor or
>>
>> Q2: How to identify actor from pqPipeline source on which are selected
>> points and how from appropriate representations to get actor which
>> contains selected points / cells?
>
> Neither of these are really supported. Look at
> vtkSelectionRepresentation. If you can think of ways of "tagging" the
> actors added by the representations used internally by this class, I
> am all ears.