[Paraview] MultiBlock Reader, RequestInformation and ParaView Display

[clinton at elemtech.com]

On Monday 21 April 2008 12:27:03 pm David C Thompson wrote:
> > I am hacking together a MultiBlock reader  for a quick demo and I was
> > wondering if there is something I can put in "RequestInformation()"
> > that can then be set into the Pipeline that will enable ParaView to
> > show how many "blocks" are in a file, before the User clicks the "OK"
> > button in ParaView?
> >
> > outInfo->Set( vtkStreamingDemandDrivenPipeline::.....(), ....);
>
> Yes. The ExodusII reader does this. Actually, the ExodusII reader
> supports several *types* of blocks (element block, face block, edge
> block, element set, side set, face set, edge set, node set). The XML
> that supports element blocks is in
> Servers/ServerManager/Resources/readers.xml:
>
>      <StringVectorProperty
>         name="ElementBlockArrayInfo"
>         information_only="1">
>         <ArraySelectionInformationHelper attribute_name="ElementBlock"/>
>      </StringVectorProperty>
>
>      <StringVectorProperty
>         name="ElementBlockArrayStatus"
>         command="SetElementBlockArrayStatus"
>         number_of_elements="2"
>         repeat_command="1"
>         number_of_elements_per_command="2"
>         element_types="2 0"
>         information_property="ElementBlockArrayInfo">
>        <ArraySelectionDomain name="array_list">
>           <RequiredProperties>
>              <Property name="ElementBlockArrayInfo" function="ArrayList"/>
>           </RequiredProperties>
>        </ArraySelectionDomain>
>      </StringVectorProperty>
>
> which points to these methods from VTK/Hybrid/vtkExodusIIReader.h:
>
>   int GetNumberOfElementBlockArrays();
>   const char* GetElementBlockArrayName(int index);
>   int GetElementBlockArrayStatus(const char* name);
>   void SetElementBlockArrayStatus(const char* name, int flag);
>
> There is a Qt panel widget (Qt/Components/pqExodusIIPanel.h) for the
> reader that displays the names (and types) of the blocks -- and allows
> users to select a subset to be loaded -- before the user presses OK.
> This panel is associated to the reader by this class:
> Qt/Components/pqObjectInspectorWidget.cxx . I don't know how a plugin
> can "suggest" its own panel be used but perhaps someone more familiar
> with plugins will chime in.
>

An auto-generated panel can handle selection of blocks, or provide a read-only 
list of blocks with an information property (there's been a bit of 
improvement since Mike last asked about read-only properties).

The exodus reader GUI has an additional set of requirements that calls for a 
custom panel, which cannot be inferred from the server manager xml.

The wiki has instructions for creating panels in plugins if its necessary.

Clint