Add and use ProcessObject::MakeRequiredOutputs

Modules/Core/Common/include/itkProcessObject.h

@@ -926,6 +926,20 @@ class ITKCommon_EXPORT ProcessObject : public Object
     return static_cast<uint32_t>(temp);
   };
 
+
+  /** Sets the required number of outputs, and creates each of them by MakeOutput. */
+  template <typename TSourceObject>
+  static void
+  MakeRequiredOutputs(TSourceObject & sourceObject, const DataObjectPointerArraySizeType numberOfRequiredOutputs)
+  {
+    sourceObject.ProcessObject::SetNumberOfRequiredOutputs(numberOfRequiredOutputs);
+
+    for (unsigned int i{}; i < numberOfRequiredOutputs; ++i)
+    {
+      sourceObject.ProcessObject::SetNthOutput(i, sourceObject.TSourceObject::MakeOutput(i));
+    }
+  }
+
   /** These ivars are made protected so filters like itkStreamingImageFilter
    * can access them directly. */
 

Modules/Filtering/DistanceMap/include/itkDanielssonDistanceMapImageFilter.hxx

@@ -30,16 +30,8 @@ namespace itk
 template <typename TInputImage, typename TOutputImage, typename TVoronoiImage>
 DanielssonDistanceMapImageFilter<TInputImage, TOutputImage, TVoronoiImage>::DanielssonDistanceMapImageFilter()
 {
-  this->SetNumberOfRequiredOutputs(3);
-
-  // distance map
-  this->SetNthOutput(0, this->MakeOutput(0));
-
-  // voronoi map
-  this->SetNthOutput(1, this->MakeOutput(1));
-
-  // distance vectors
-  this->SetNthOutput(2, this->MakeOutput(2));
+  // Make the outputs (distance map, voronoi map, distance vectors).
+  ProcessObject::MakeRequiredOutputs(*this, 3);
 
   m_SquaredDistance = false;
   m_InputIsBinary = false;

Modules/Filtering/DistanceMap/include/itkSignedDanielssonDistanceMapImageFilter.hxx

@@ -32,16 +32,8 @@ template <typename TInputImage, typename TOutputImage, typename TVoronoiImage>
 SignedDanielssonDistanceMapImageFilter<TInputImage, TOutputImage, TVoronoiImage>::
   SignedDanielssonDistanceMapImageFilter()
 {
-  this->SetNumberOfRequiredOutputs(3);
-
-  // distance map
-  this->SetNthOutput(0, static_cast<OutputImageType *>(this->MakeOutput(0).GetPointer()));
-
-  // voronoi map
-  this->SetNthOutput(1, static_cast<VoronoiImageType *>(this->MakeOutput(1).GetPointer()));
-
-  // distance vectors
-  this->SetNthOutput(2, static_cast<VectorImageType *>(this->MakeOutput(2).GetPointer()));
+  // Make the outputs (distance map, voronoi map, distance vectors).
+  ProcessObject::MakeRequiredOutputs(*this, 3);
 
   // Default values
   this->m_SquaredDistance = false; // Should we remove this ?

Modules/Numerics/Eigen/include/itkEigenAnalysis2DImageFilter.hxx

@@ -28,10 +28,7 @@ template <typename TInputImage, typename TEigenValueImage, typename TEigenVector
 EigenAnalysis2DImageFilter<TInputImage, TEigenValueImage, TEigenVectorImage>::EigenAnalysis2DImageFilter()
 {
   this->SetNumberOfRequiredInputs(3);
-  this->SetNumberOfRequiredOutputs(3);
-  this->SetNthOutput(0, this->MakeOutput(0));
-  this->SetNthOutput(1, this->MakeOutput(1));
-  this->SetNthOutput(2, this->MakeOutput(2));
+  ProcessObject::MakeRequiredOutputs(*this, 3);
   static_assert(EigenVectorType::Dimension == 2, "Error: PixelType of EigenVector Image must have exactly 2 elements!");
 }
 

Modules/Numerics/Statistics/include/itkCovarianceSampleFilter.h

@@ -121,12 +121,6 @@ class ITK_TEMPLATE_EXPORT CovarianceSampleFilter : public ProcessObject
   MeasurementVectorSizeType
   GetMeasurementVectorSize() const;
 
-protected:
-  CovarianceSampleFilter();
-  ~CovarianceSampleFilter() override = default;
-  void
-  PrintSelf(std::ostream & os, Indent indent) const override;
-
   /** DataObject pointer */
   using DataObjectPointer = DataObject::Pointer;
 
@@ -135,6 +129,12 @@ class ITK_TEMPLATE_EXPORT CovarianceSampleFilter : public ProcessObject
   DataObjectPointer
   MakeOutput(DataObjectPointerArraySizeType index) override;
 
+protected:
+  CovarianceSampleFilter();
+  ~CovarianceSampleFilter() override = default;
+  void
+  PrintSelf(std::ostream & os, Indent indent) const override;
+
   void
   GenerateData() override;
 }; // end of class

Modules/Numerics/Statistics/include/itkCovarianceSampleFilter.hxx

@@ -28,10 +28,7 @@ template <typename TSample>
 CovarianceSampleFilter<TSample>::CovarianceSampleFilter()
 {
   this->ProcessObject::SetNumberOfRequiredInputs(1);
-  this->ProcessObject::SetNumberOfRequiredOutputs(2);
-
-  this->ProcessObject::SetNthOutput(0, this->MakeOutput(0));
-  this->ProcessObject::SetNthOutput(1, this->MakeOutput(1));
+  ProcessObject::MakeRequiredOutputs(*this, 2);
 }
 
 template <typename TSample>

Modules/Numerics/Statistics/include/itkStandardDeviationPerComponentSampleFilter.h

@@ -98,12 +98,6 @@ class ITK_TEMPLATE_EXPORT StandardDeviationPerComponentSampleFilter : public Pro
   const MeasurementVectorRealDecoratedType *
   GetMeanPerComponentOutput() const;
 
-protected:
-  StandardDeviationPerComponentSampleFilter();
-  ~StandardDeviationPerComponentSampleFilter() override = default;
-  void
-  PrintSelf(std::ostream & os, Indent indent) const override;
-
   /** DataObject pointer */
   using DataObjectPointer = DataObject::Pointer;
 
@@ -112,6 +106,12 @@ class ITK_TEMPLATE_EXPORT StandardDeviationPerComponentSampleFilter : public Pro
   DataObjectPointer
   MakeOutput(DataObjectPointerArraySizeType index) override;
 
+protected:
+  StandardDeviationPerComponentSampleFilter();
+  ~StandardDeviationPerComponentSampleFilter() override = default;
+  void
+  PrintSelf(std::ostream & os, Indent indent) const override;
+
   void
   GenerateData() override;
 

Modules/Numerics/Statistics/include/itkStandardDeviationPerComponentSampleFilter.hxx

@@ -29,10 +29,7 @@ template <typename TSample>
 StandardDeviationPerComponentSampleFilter<TSample>::StandardDeviationPerComponentSampleFilter()
 {
   this->ProcessObject::SetNumberOfRequiredInputs(1);
-  this->ProcessObject::SetNumberOfRequiredOutputs(2);
-
-  this->ProcessObject::SetNthOutput(0, this->MakeOutput(0));
-  this->ProcessObject::SetNthOutput(1, this->MakeOutput(1));
+  ProcessObject::MakeRequiredOutputs(*this, 2);
 }
 
 template <typename TSample>

Modules/Registration/Common/include/itkBlockMatchingImageFilter.h

@@ -160,12 +160,12 @@ class ITK_TEMPLATE_EXPORT BlockMatchingImageFilter : public MeshToMeshFilter<TFe
     return dynamic_cast<SimilaritiesType *>(this->ProcessObject::GetOutput(1));
   }
 
-protected:
   /** MakeOutput is provided for handling multiple outputs */
   using Superclass::MakeOutput;
   DataObject::Pointer
   MakeOutput(ProcessObject::DataObjectPointerArraySizeType idx) override;
 
+protected:
   /** We need to create our own GenerateOutputInformation because the
    * default version from ProcessObject result in a dynamic_cast of the input
    * pointer to the output pointer type in PointSet::CopyInformation.  This does

Modules/Registration/Common/include/itkBlockMatchingImageFilter.hxx

@@ -39,13 +39,8 @@ BlockMatchingImageFilter<TFixedImage, TMovingImage, TFeatures, TDisplacements, T
   this->m_BlockRadius.Fill(2);
   this->m_SearchRadius.Fill(3);
 
-  // make the outputs
-  this->ProcessObject::SetNumberOfRequiredOutputs(2);
-  typename DisplacementsType::Pointer displacements =
-    static_cast<DisplacementsType *>(this->MakeOutput(0).GetPointer());
-  this->SetNthOutput(0, displacements.GetPointer());
-  typename SimilaritiesType::Pointer similarities = static_cast<SimilaritiesType *>(this->MakeOutput(1).GetPointer());
-  this->SetNthOutput(1, similarities.GetPointer());
+  // Make the outputs (Displacements, Similarities).
+  ProcessObject::MakeRequiredOutputs(*this, 2);
 
   // all inputs are required
   this->SetPrimaryInputName("FeaturePoints");

Modules/Segmentation/Watersheds/include/itkWatershedSegmenter.hxx

@@ -1354,13 +1354,9 @@ Segmenter<TInputImage>::Segmenter()
   m_SortEdgeLists = true;
   m_Connectivity.direction = nullptr;
   m_Connectivity.index = nullptr;
-  typename OutputImageType::Pointer  img = static_cast<OutputImageType *>(this->MakeOutput(0).GetPointer());
-  typename SegmentTableType::Pointer st = static_cast<SegmentTableType *>(this->MakeOutput(1).GetPointer());
-  typename BoundaryType::Pointer     bd = static_cast<BoundaryType *>(this->MakeOutput(2).GetPointer());
-  this->SetNumberOfRequiredOutputs(3);
-  this->ProcessObject::SetNthOutput(0, img.GetPointer());
-  this->ProcessObject::SetNthOutput(1, st.GetPointer());
-  this->ProcessObject::SetNthOutput(2, bd.GetPointer());
+
+  // Make the outputs (OutputImage, SegmentTable, Boundary).
+  ProcessObject::MakeRequiredOutputs(*this, 3);
 
   // Allocate memory for connectivity
   m_Connectivity.size = 2 * ImageDimension;