Method RequestData

Filters/Modeling/vtkContourLoopExtraction.cxx:317–453

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

//------------------------------------------------------------------------------
int vtkContourLoopExtraction::RequestData(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the info objects
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkPolyData* input = vtkPolyData::SafeDownCast(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData* output = vtkPolyData::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // Initialize and check data
  vtkDebugMacro(<< "Loop extraction...");

  vtkPoints* points = input->GetPoints();
  vtkIdType numPts;
  if (!points || (numPts = input->GetNumberOfPoints()) < 1)
  {
    vtkErrorMacro("Input contains no points");
    return 1;
  }

  vtkCellArray* lines = input->GetLines();
  vtkIdType numLines = lines->GetNumberOfCells();
  if (numLines < 1)
  {
    vtkErrorMacro("Input contains no lines");
    return 1;
  }

  vtkPointData* inPD = input->GetPointData();

  vtkDataArray* scalars = nullptr;
  if (this->ScalarThresholding)
  {
    scalars = inPD->GetScalars();
  }

  // Prepare output
  output->SetPoints(points);
  vtkSmartPointer<vtkCellArray> outLines;
  vtkSmartPointer<vtkCellArray> outPolys;

  if (this->OutputMode == VTK_OUTPUT_POLYLINES || this->OutputMode == VTK_OUTPUT_BOTH)
  {
    outLines.TakeReference(vtkCellArray::New());
    output->SetLines(outLines);
  }
  if (this->OutputMode == VTK_OUTPUT_POLYGONS || this->OutputMode == VTK_OUTPUT_BOTH)
  {
    outPolys.TakeReference(vtkCellArray::New());
    output->SetPolys(outPolys);
  }
  output->GetPointData()->PassData(inPD);

  // Create a clean polydata containing only line segments and without other
  // topological types. This simplifies the filter.
  vtkIdType npts;