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

[Utkarsh Ayachit]

>     - 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.