Function vtkImageReader2Update

IO/Image/vtkImageReader2.cxx:601–674

// templated to handle different data types.
template <class OT>
void vtkImageReader2Update(vtkImageReader2* self, vtkImageData* data, OT* outPtr)
{
  vtkIdType outIncr[3];
  OT *outPtr1, *outPtr2;
  long streamRead;
  int idx1, idx2, nComponents;
  int outExtent[6];
  unsigned long count = 0;
  unsigned long target;

  // Get the requested extents and increments
  data->GetExtent(outExtent);
  data->GetIncrements(outIncr);
  nComponents = data->GetNumberOfScalarComponents();

  // length of a row, num pixels read at a time
  int pixelRead = outExtent[1] - outExtent[0] + 1;
  streamRead = (long)(pixelRead * nComponents * sizeof(OT));

  // create a buffer to hold a row of the data
  target =
    (unsigned long)((outExtent[5] - outExtent[4] + 1) * (outExtent[3] - outExtent[2] + 1) / 50.0);
  target++;

  // read the data row by row
  if (self->GetFileDimensionality() == 3)
  {
    self->ComputeInternalFileName(0);
    if (!self->OpenFile())
    {
      return;
    }
  }
  outPtr2 = outPtr;
  for (idx2 = outExtent[4]; idx2 <= outExtent[5]; ++idx2)
  {
    if (self->GetFileDimensionality() == 2)
    {
      self->ComputeInternalFileName(idx2);
      if (!self->OpenFile())
      {
        return;
      }
    }
    outPtr1 = outPtr2;
    for (idx1 = outExtent[2]; !self->AbortExecute && idx1 <= outExtent[3]; ++idx1)
    {
      if (!(count % target))
      {
        self->UpdateProgress(count / (50.0 * target));
      }
      count++;

      // seek to the correct row
      self->SeekFile(outExtent[0], idx1, idx2);
      // read the row.
      if (!self->GetFile()->read((char*)outPtr1, streamRead))
      {