[vtk-developers] Intersecting tables, documentation, and me

[Kerr, Robert]

Recently I've been working on something that involves vtkExtractSelectedRows.  I finally got my issues (well, at least my programming ones) worked out, and everything is peachy-keen.  But it was harder than I'd expected.  Here's a description of some of my frustration.


Here's what I read about vtkExtractSelectedRows:

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Detailed Description

return selected rows of a table

The first input is a vtkTable to extract rows from. The second input is a vtkSelection containing the selected indices. The third input is a vtkAnnotationLayers containing selected indices. The field type of the input selection is ignored when converted to row indices.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

And yet, the first input isn't a vtkTable, rather it's a vtkAlgorithmOutput.  The second input is not a vtkSelection, rather it also is a vtkAlgorithmOutput.

Scrabbling around through the docs, I found a link to a test case for vtkExtractSelectedRows, and was able to figure out the correct voodoo to make it work, but it certainly wasn't clear from the documentation.

Is it just "understood" that when we say an input is a vtkTable we instead mean vtkTable->GetProducerPort() and so on?  Is this written anywhere in the docs?  I know I'm probably exposing my abysmal ignorance of all things VTK by speaking out here, but neither would I want to contribute to the VTK Conspiracy of 1492, which (I imagine) states that "knowing how to convert from a vtkTable to a vtkAlgorithmOutput is implicitly required for anyone using VTK".

Thanks

-bob
Meddle not in the affairs of wizards, for they are subtle and
quick to anger.
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   Robert Kerr,  Titan Informatics Toolkit Developer
   rakerr at sandia.gov         |    PO Box 5800,  MS 1323
   Phone: (505) 844-8606    |    Sandia National Labs
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