Method RequestData

Filters/Extraction/vtkExtractSelection.cxx:239–477

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
int vtkExtractSelection::RequestData(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  vtkDataObject* input = vtkDataObject::GetData(inputVector[0], 0);
  vtkSelection* selection = vtkSelection::GetData(inputVector[1], 0);
  vtkDataObject* output = vtkDataObject::GetData(outputVector, 0);
  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  // If no input, error
  if (!input)
  {
    vtkErrorMacro(<< "No input specified");
    return 0;
  }

  // If no selection, quietly select nothing
  if (!selection)
  {
    return 1;
  }

  // preserve only nodes that their processId matches the current processId
  if (outInfo->Has(vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER()))
  {
    int processId = outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER());
    vtkTrimSelection(selection, processId);
  }

  // check for empty selection
  if (selection->GetNumberOfNodes() == 0)
  {
    return 1;
  }

  // check for select FieldType consistency right here and return failure
  // if they are not consistent.
  bool sane;
  const auto assoc = this->GetAttributeTypeOfSelection(selection, sane);
  if (!sane || assoc == vtkDataObject::NUMBER_OF_ATTRIBUTE_TYPES)
  {
    vtkErrorMacro("Selection has selection nodes with inconsistent field types.");
    return 0;
  }

  // Create operators for each of vtkSelectionNode instances and initialize them.
  std::map<std::string, vtkSmartPointer<vtkSelector>> selectors;
  for (unsigned int cc = 0, max = selection->GetNumberOfNodes(); cc < max; ++cc)
  {
    auto node = selection->GetNode(cc);
    auto name = selection->GetNodeNameAtIndex(cc);

    if (auto anOperator = this->NewSelectionOperator(
          static_cast<vtkSelectionNode::SelectionContent>(node->GetContentType())))
    {
      anOperator->SetInsidednessArrayName(name);
      anOperator->Initialize(node);
      selectors[name] = anOperator;
    }