Function GetMatrix

Examples/ConvertTransformFile.cxx:79–156

 */
template <typename TTransform>
bool
GetMatrix(const typename TTransform::Pointer & transform, typename TTransform::MatrixType & matrix, bool outputRAS)
{
  const unsigned int ImageDimension = TTransform::InputSpaceDimension;

  using ScalarType = typename TTransform::ScalarType;

  matrix.Fill(itk::NumericTraits<typename TTransform::ScalarType>::ZeroValue());
  bool done = false;

  // Matrix-offset derived
  {
    using CastTransformType = itk::MatrixOffsetTransformBase<ScalarType, ImageDimension, ImageDimension>;
    typename CastTransformType::Pointer castTransform = dynamic_cast<CastTransformType *>(transform.GetPointer());

    if (castTransform.IsNotNull())
    {
      matrix = castTransform->GetMatrix();
      done = true;
    }
  }

  // Translation
  if (!done)
  {
    using CastTransformType = itk::TranslationTransform<ScalarType, ImageDimension>;
    typename CastTransformType::Pointer castTransform = dynamic_cast<CastTransformType *>(transform.GetPointer());

    if (castTransform.IsNotNull())
    {
      for (unsigned int i = 0; i < ImageDimension; i++)
      {
        matrix(i, i) = itk::NumericTraits<typename TTransform::ScalarType>::OneValue();
      }
      done = true;
    }
  }

  // Identity
  if (!done)
  {
    using CastTransformType = itk::IdentityTransform<ScalarType, ImageDimension>;
    typename CastTransformType::Pointer castTransform = dynamic_cast<CastTransformType *>(transform.GetPointer());

    if (castTransform.IsNotNull())
    {
      for (unsigned int i = 0; i < ImageDimension; i++)
      {
        matrix(i, i) = itk::NumericTraits<typename TTransform::ScalarType>::OneValue();
      }
      done = true;
    }
  }

  if (!done)
  {
    // Unsupported transform type
    return false;