Method RequestData

Infovis/Core/vtkContinuousScatterplot.cxx:86–932

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}
//------------------------------------------------------------------------------
int vtkContinuousScatterplot::RequestData(
  vtkInformation*, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // get the input and output ports information.
  vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  // get the input data set, which is required to be a vtkUnstructuredGrid.
  vtkUnstructuredGrid* input =
    vtkUnstructuredGrid::SafeDownCast(inInfo->Get(vtkDataObject::DATA_OBJECT()));
  // get the output data set, which is required to be a vtkImageData.
  vtkImageData* output = vtkImageData::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // get the number of points and cells of the input grid.
  vtkIdType numCells = input->GetNumberOfCells();
  vtkIdType numPts = input->GetNumberOfPoints();

  // get the dataset statistics and check if it is not an empty grid.
  if (numCells < 1 || numPts < 1)
  {
    vtkErrorMacro("No input data.");
    return 1;
  }

  // check if the output image resolution is a valid number.
  if (this->ResX <= 0 || this->ResY <= 0)
  {
    vtkErrorMacro("The resolution of the output image has to be a positive number.");
    return 1;
  }

  // check if the names of the input scalar fields are specified.
  if (!this->Fields[0] || !this->Fields[1])
  {
    vtkErrorMacro("At least two fields need to be specified.");
    return 1;
  }

  // Input point data, which should include the arrays defining the range space.
  vtkDataSetAttributes* inPD = input->GetPointData();
  // current data array of the given array names from the user input.
  vtkSmartPointer<vtkDataArray> array;
  // scalar range in two fields, where fieldInterval[0] = f1_max - f1_min,
  // fieldInterval[1] = f2_max - f2_min
  float fieldInterval[2];

  // fragment width of two fields, where fragWidth[0] = fieldInterval[0] / resX,
  // fragWidth[0] = fieldInterval[1] / resY, (resX, resY) is the output image
  // resolution.
  float fragWidth[2];

  // Collect the first scalar field based on array names,
  array = inPD->GetArray(this->Fields[0]);
  // confirming that this field is present in the input.
  if (array)
  {
    // Collect field ranges for later use.
    fieldInterval[0] = array->GetRange()[1] - array->GetRange()[0];