Method RequestData

Common/ExecutionModel/vtkThreadedImageAlgorithm.cxx:497–631

------------------------------------------------------------------------------ This is the superclasses style of Execute method. Convert it into an imaging style Execute method.

// This is the superclasses style of Execute method.  Convert it into
// an imaging style Execute method.
int vtkThreadedImageAlgorithm::RequestData(
  vtkInformation* request, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  // count the total number of inputs, outputs
  int numInputPorts = this->GetNumberOfInputPorts();
  int numOutputPorts = this->GetNumberOfOutputPorts();
  int numDataObjects = numOutputPorts;
  for (int i = 0; i < numInputPorts; i++)
  {
    numDataObjects += inputVector[i]->GetNumberOfInformationObjects();
  }

  // ThreadedRequestData() needs to be given the inputs and outputs
  // as raw pointers, but we use std::vector for memory allocation
  vtkImageData*** inputs = nullptr;
  vtkImageData** outputs = nullptr;
  std::vector<vtkImageData*> connections(numDataObjects);
  std::vector<vtkImageData**> ports(numInputPorts);
  size_t offset = 0;

  // set pointers to the lists of data objects and input ports
  if (numInputPorts)
  {
    inputs = ports.data();
    for (int i = 0; i < numInputPorts; i++)
    {
      inputs[i] = &connections[offset];
      offset += inputVector[i]->GetNumberOfInformationObjects();
    }
  }

  // set pointer to the list of output data objects
  if (numOutputPorts)
  {
    outputs = &connections[offset];
  }

  // allocate the output data and call CopyAttributeData
  this->PrepareImageData(inputVector, outputVector, inputs, outputs);

  // need bytes per voxel to compute block size
  int bytesPerVoxel = 1;

  // get the update extent from the output, if there is an output
  int updateExtent[6] = { 0, -1, 0, -1, 0, -1 };
  if (numOutputPorts)
  {
    vtkImageData* outData = outputs[0];
    if (outData)
    {
      bytesPerVoxel = (outData->GetScalarSize() * outData->GetNumberOfScalarComponents());
      outData->GetExtent(updateExtent);
    }
  }
  else
  {
    // if no output, get update extent from the first input
    for (int inPort = 0; inPort < numInputPorts; inPort++)