ENH: Support generic linear Transform

Replace TransformGeometryImageFilter::SetRigidTransform with
SetTransform, while adding support for generic linear transform. The
Transform::ApplyToImageMetadata method is re-used for computation.

Modules/Core/Transform/include/itkTransformGeometryImageFilter.h

@@ -139,11 +139,11 @@ class ITK_TEMPLATE_EXPORT TransformGeometryImageFilter : public InPlaceImageFilt
 #endif
 
   /** Transform type alias */
-  using RigidTransformType = VersorRigid3DTransform<double>;
-  using RigidTransformConstPointer = typename RigidTransformType::ConstPointer;
+  using TransformType = Transform<double, InputImageDimension, OutputImageDimension>;
+  using TransformConstPointer = typename TransformType::ConstPointer;
 
   /** Set/Get required rigid transform. */
-  itkSetGetDecoratedObjectInputMacro(RigidTransform, RigidTransformType);
+  itkSetGetDecoratedObjectInputMacro(Transform, TransformType);
 
   /** Set/Get required input image. (A wrapper to this->Set/GetInput()) */
   itkSetInputMacro(InputImage, InputImageType);
@@ -156,6 +156,9 @@ class ITK_TEMPLATE_EXPORT TransformGeometryImageFilter : public InPlaceImageFilt
   void
   GenerateOutputInformation() override;
 
+  void
+  VerifyPreconditions() ITKv5_CONST override;
+
   void
   GenerateData() override;
 };

Modules/Core/Transform/include/itkTransformGeometryImageFilter.hxx

@@ -32,7 +32,21 @@ TransformGeometryImageFilter<TInputImage, TOutputImage>::TransformGeometryImageF
   Self::SetPrimaryInputName("InputImage");
 
   // "RigidTransform" required ( not numbered )
-  Self::AddRequiredInputName("RigidTransform");
+  Self::AddRequiredInputName("Transform");
+}
+
+template <typename TInputImage, typename TOutputImage>
+void
+TransformGeometryImageFilter<TInputImage, TOutputImage>::VerifyPreconditions() ITKv5_CONST
+{
+  Superclass::VerifyPreconditions();
+
+  TransformConstPointer tx = this->GetTransform();
+
+  if (!tx->IsLinear())
+  {
+    itkExceptionMacro(<< "Transform set to non-linear transform of type: " << tx->GetNameOfClass());
+  }
 }
 
 
@@ -43,25 +57,10 @@ TransformGeometryImageFilter<TInputImage, TOutputImage>::GenerateOutputInformati
 
   Superclass::GenerateOutputInformation();
 
-  OutputImageType *      outputPtr = this->GetOutput();
-  const InputImageType * inputPtr = this->GetInputImage();
+  OutputImageType * outputPtr = this->GetOutput();
 
-  //  SEE HEADER FILE FOR MATH DESCRIPTION
-  RigidTransformConstPointer                    FMTxfm = this->GetRigidTransform();
-  const typename RigidTransformType::MatrixType inverseRotation(FMTxfm->GetMatrix().GetInverse());
-
-  // Modify the origin and direction info of the image to reflect the transform.
-  Vector<double, 3> newOriginVector =
-    inverseRotation * (inputPtr->GetOrigin().GetVectorFromOrigin() - FMTxfm->GetCenter().GetVectorFromOrigin() -
-                       FMTxfm->GetTranslation()) // NewOrigin = [R^-1] * ( O - C - T ) + C
-    + FMTxfm->GetCenter().GetVectorFromOrigin();
-  Point<double, 3> newOriginPoint;
-  for (int i = 0; i < 3; ++i)
-  {
-    newOriginPoint[i] = newOriginVector[i];
-  }
-  outputPtr->SetOrigin(newOriginPoint);
-  outputPtr->SetDirection(inverseRotation * inputPtr->GetDirection()); // NewDC = [R^-1][DC]
+  TransformConstPointer tx = this->GetTransform();
+  tx->ApplyToImageMetadata(outputPtr);
 }
 
 

Modules/Core/Transform/test/itkTransformGeometryImageFilterTest.cxx

@@ -135,8 +135,8 @@ itkTransformGeometryImageFilterTest(int argc, char * argv[])
 
   filter->SetInputImage(inputImage);
   ITK_TEST_SET_GET_VALUE(inputImage, filter->GetInputImage());
-  filter->SetRigidTransform(transform);
-  ITK_TEST_SET_GET_VALUE(transform, filter->GetRigidTransform());
+  filter->SetTransform(transform);
+  ITK_TEST_SET_GET_VALUE(transform, filter->GetTransform());
   ITK_TRY_EXPECT_NO_EXCEPTION(filter->Update());
   ImagePointer outputImage = filter->GetOutput();
   ITK_TRY_EXPECT_NO_EXCEPTION(itk::WriteImage(outputImage, argv[3]));