Pipeline compatibility

siver · January 23, 2020, 10:54am

Dear devs,

I have two C++ plugins, A (source) and B (filter). However B uses additional data that only source A can provide. Therefore, in a pipeline, A-B is perfectly fine, while A-C-B (where C is some other filter) should not be possible.

Also I noticed that unavailable filters are gray and cannot be selected in PV.

My questions are:

How does PV decides what filters can be used?
How can I reproduce this effect for my source and filter?

Thanks a ton,
Art

michal.wozniak · January 23, 2020, 3:37pm

Hi,

each filter have a corresponding XML which define its inputs data type

eg: vtkAppendArcLength : input restricted to vtkPolyData , therefore this filter won’t be able to select a vtkUnstructured data

vtkAppendArcLength will be gray

        <DataTypeDomain name="input_type">
          <DataType value="vtkPolyData" />
        </DataTypeDomain>

github.com

Kitware/ParaView/blob/master/Remoting/Application/Resources/filters_filterscore.xml

<ServerManagerConfiguration>
  <ProxyGroup name="filters">
    <!-- ==================================================================== -->
    <SourceProxy class="vtkAppendArcLength"
                 label="Append Arc-Length"
                 name="AppendArcLength">
      <Documentation long_help="Appends Arc length for input poly lines."
                     short_help="Appends Arc length for input poly lines.">
                     vtkAppendArcLength is used for filter such as
                     plot-over-line. In such cases, we need to add an attribute
                     array that is the arc_length over the length of the probed
                     line. That's when vtkAppendArcLength can be used. It adds
                     a new point-data array named "arc_length" with the
                     computed arc length for each of the polylines in the
                     input. For all other cell types, the arc length is set to
                     0.</Documentation>
      <InputProperty command="SetInputConnection"
                     name="Input">
        <ProxyGroupDomain name="groups">
          <Group name="sources" />

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siver · January 23, 2020, 4:16pm

Hello, thank you for your reply.

I was hoping for something more sensitive. In our case, the source always comes with a certain variable. And if the variable is not present, the filter should not be available.

I could still have a vtkPolyData without this variable, and yet ParaView will fail.

Sincerely,
Art

cory.quammen · January 23, 2020, 7:26pm

That’s not currently possible. One could extend vtkSMInputArrayDomain to add an XML attribute that specifies which array names must be present, then add an InputArrayDomain entry to the InputProperty element in your filter XML definition.

siver · January 24, 2020, 2:14pm

Doesn’t sound like something a plugin can do.

Either way, DataTypes is the answer.

Thank you very much for your help,
Art