Method ComputeInverseTransformedExtent

IO/Image/vtkImageReader.cxx:540–624

}

void vtkImageReader::ComputeInverseTransformedExtent(int inExtent[6], int outExtent[6])
{
  double transformedExtent[3];
  int temp;
  int idx;

  if (!this->Transform)
  {
    memcpy(outExtent, inExtent, 6 * sizeof(int));
    for (idx = 0; idx < 6; idx += 2)
    {
      // do the slide to 000 origin by subtracting the minimum extent
      outExtent[idx] += this->DataExtent[idx];
      outExtent[idx + 1] += this->DataExtent[idx];
    }
  }
  else
  {
    // need to know how far to translate to start at 000
    int dataExtent[6];
    // first transform the data extent
    transformedExtent[0] = this->DataExtent[0];
    transformedExtent[1] = this->DataExtent[2];
    transformedExtent[2] = this->DataExtent[4];
    this->Transform->TransformPoint(transformedExtent, transformedExtent);
    dataExtent[0] = (int)transformedExtent[0];
    dataExtent[2] = (int)transformedExtent[1];
    dataExtent[4] = (int)transformedExtent[2];

    transformedExtent[0] = this->DataExtent[1];
    transformedExtent[1] = this->DataExtent[3];
    transformedExtent[2] = this->DataExtent[5];
    this->Transform->TransformPoint(transformedExtent, transformedExtent);
    dataExtent[1] = (int)transformedExtent[0];
    dataExtent[3] = (int)transformedExtent[1];
    dataExtent[5] = (int)transformedExtent[2];

    for (idx = 0; idx < 6; idx += 2)
    {
      if (dataExtent[idx] > dataExtent[idx + 1])
      {
        temp = dataExtent[idx];
        dataExtent[idx] = dataExtent[idx + 1];
        dataExtent[idx + 1] = temp;
      }
    }

    for (idx = 0; idx < 6; idx += 2)
    {
      // do the slide to 000 origin by subtracting the minimum extent
      inExtent[idx] += dataExtent[idx];
      inExtent[idx + 1] += dataExtent[idx];
    }

    transformedExtent[0] = inExtent[0];
    transformedExtent[1] = inExtent[2];
    transformedExtent[2] = inExtent[4];
    this->Transform->GetLinearInverse()->TransformPoint(transformedExtent, transformedExtent);