STYLE: Use {}-initialization for zero-filled FixedArray-derived types

hjmjohnson · claude · hjmjohnson · commit 787267e06bb7 · 2026-04-04T11:29:07.000-05:00
Using find_declare_then_init.py --pattern fill_zero, replaced the two-line pattern: Type var; var.Fill(0); with the single-line value-initialization: Type var{}; {}-initialization zero-initializes all elements for FixedArray and its subclasses (IndexType, SizeType, SpacingType, PointType, VectorType, etc.), which is the canonical C++ idiom for zero-initialization and preserves the correct derived type (unlike ::Filled(0) which returns the base class). Applies to 25 files in Modules/ (excluding Remote/, BridgeOpenCV, BridgeVXL). Follow-up to commit 427df79 by hjmjohnson "STYLE: Use {}-initialization for zero-filled FixedArray-derived types" Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
diff --git a/Modules/Core/ImageFunction/include/itkGaussianInterpolateImageFunction.hxx b/Modules/Core/ImageFunction/include/itkGaussianInterpolateImageFunction.hxx
@@ -109,13 +109,10 @@ GaussianInterpolateImageFunction<TImageType, TCoordinate>::EvaluateAtContinuousI
 
   RealType  sum_me = 0.0;
   RealType  sum_m = 0.0;
-  ArrayType dsum_me;
-  ArrayType dsum_m;
-  ArrayType dw;
+  ArrayType dsum_me{};
+  ArrayType dsum_m{};
+  ArrayType dw{};
 
-  dsum_m.Fill(0.0);
-  dsum_me.Fill(0.0);
-  dw.Fill(0.0);
 
   for (ImageRegionConstIteratorWithIndex It(this->GetInputImage(), region); !It.IsAtEnd(); ++It)
   {
diff --git a/Modules/Core/ImageFunction/test/itkGaussianInterpolateImageFunctionTest.cxx b/Modules/Core/ImageFunction/test/itkGaussianInterpolateImageFunctionTest.cxx
@@ -49,10 +49,9 @@ itkGaussianInterpolateImageFunctionTest(int, char *[])
   image->SetRegions(region);
   image->Allocate();
 
-  ImageType::PointType origin;
+  ImageType::PointType origin{};
   auto                 spacing = itk::MakeFilled<ImageType::SpacingType>(1.0);
 
-  origin.Fill(0.0);
 
   image->SetOrigin(origin);
   image->SetSpacing(spacing);
diff --git a/Modules/Core/ImageFunction/test/itkNearestNeighborInterpolateImageFunctionTest.cxx b/Modules/Core/ImageFunction/test/itkNearestNeighborInterpolateImageFunctionTest.cxx
@@ -71,10 +71,9 @@ itkNearestNeighborInterpolateImageFunctionTest(int, char *[])
   variablevectorimage->SetRegions(region);
   variablevectorimage->Allocate();
 
-  ImageType::PointType origin;
+  ImageType::PointType origin{};
   auto                 spacing = itk::MakeFilled<ImageType::SpacingType>(1.0);
 
-  origin.Fill(0.0);
 
   image->SetOrigin(origin);
   image->SetSpacing(spacing);
diff --git a/Modules/Filtering/DisplacementField/test/itkComposeDisplacementFieldsImageFilterTest.cxx b/Modules/Filtering/DisplacementField/test/itkComposeDisplacementFieldsImageFilterTest.cxx
@@ -28,13 +28,12 @@ itkComposeDisplacementFieldsImageFilterTest(int, char *[])
   using DisplacementFieldType = itk::Image<VectorType, ImageDimension>;
 
   // Create a displacement field
-  DisplacementFieldType::PointType     origin;
+  DisplacementFieldType::PointType     origin{};
   auto                                 spacing = itk::MakeFilled<DisplacementFieldType::SpacingType>(0.5);
   auto                                 size = itk::MakeFilled<DisplacementFieldType::SizeType>(100);
   DisplacementFieldType::DirectionType direction;
 
   direction.SetIdentity();
-  origin.Fill(0.0);
 
   auto ones = itk::MakeFilled<VectorType>(1);
 
diff --git a/Modules/Filtering/DisplacementField/test/itkDisplacementFieldToBSplineImageFilterTest.cxx b/Modules/Filtering/DisplacementField/test/itkDisplacementFieldToBSplineImageFilterTest.cxx
@@ -29,13 +29,12 @@ itkDisplacementFieldToBSplineImageFilterTest(int, char *[])
   using PointSetType = itk::PointSet<VectorType, ImageDimension>;
 
   // Create a displacement field
-  DisplacementFieldType::PointType     origin;
+  DisplacementFieldType::PointType     origin{};
   auto                                 spacing = itk::MakeFilled<DisplacementFieldType::SpacingType>(0.5);
   auto                                 size = itk::MakeFilled<DisplacementFieldType::SizeType>(100);
   DisplacementFieldType::DirectionType direction;
 
   direction.SetIdentity();
-  origin.Fill(0.0);
 
   auto ones = itk::MakeFilled<VectorType>(1);
 
diff --git a/Modules/Filtering/DisplacementField/test/itkInvertDisplacementFieldImageFilterTest.cxx b/Modules/Filtering/DisplacementField/test/itkInvertDisplacementFieldImageFilterTest.cxx
@@ -37,13 +37,12 @@ itkInvertDisplacementFieldImageFilterTest(int argc, char * argv[])
   using DisplacementFieldType = itk::Image<VectorType, ImageDimension>;
 
   // Create a displacement field
-  DisplacementFieldType::PointType     origin;
+  DisplacementFieldType::PointType     origin{};
   auto                                 spacing = itk::MakeFilled<DisplacementFieldType::SpacingType>(0.5);
   auto                                 size = itk::MakeFilled<DisplacementFieldType::SizeType>(100);
   DisplacementFieldType::DirectionType direction;
 
   direction.SetIdentity();
-  origin.Fill(0.0);
 
   auto ones = itk::MakeFilled<VectorType>(1);
 
diff --git a/Modules/Filtering/ImageGradient/test/itkGradientRecursiveGaussianFilterTest3.cxx b/Modules/Filtering/ImageGradient/test/itkGradientRecursiveGaussianFilterTest3.cxx
@@ -200,9 +200,8 @@ itkGradientRecursiveGaussianFilterTest3(int argc, char * argv[])
   using myImageVector1DType = itk::Image<myVector1DType, myDimension>;
 
   myGradImage1DType::Pointer vector1DGradImage = nullptr;
-  myVector1DType             vector1Dborder;
+  myVector1DType             vector1Dborder{};
   auto                       vector1Dfill = itk::MakeFilled<myVector1DType>(100.0);
-  vector1Dborder.Fill(0.0);
   int runResult = itkGradientRecursiveGaussianFilterTest3Run<myImageVector1DType, myGradImage1DType, myComponents1D>(
     vector1Dborder, vector1Dfill, vector1DGradImage, argv[1]);
   if (runResult == EXIT_FAILURE)
diff --git a/Modules/Filtering/ImageGrid/test/itkBSplineControlPointImageFunctionTest.cxx b/Modules/Filtering/ImageGrid/test/itkBSplineControlPointImageFunctionTest.cxx
@@ -37,9 +37,8 @@ itkBSplineControlPointImageFunctionTest(int, char *[])
 
   auto                       size = itk::MakeFilled<VectorImageType::SizeType>(4);
   auto                       spacing = itk::MakeFilled<VectorImageType::SpacingType>(1.0);
-  VectorImageType::PointType origin;
+  VectorImageType::PointType origin{};
 
-  origin.Fill(0.0);
   phiLattice->SetOrigin(origin);
   phiLattice->SetSpacing(spacing);
   phiLattice->SetRegions(size);
@@ -48,9 +47,8 @@ itkBSplineControlPointImageFunctionTest(int, char *[])
   // To create the specified function, the first and last control points have
   // a value of 1.0;
 
-  VectorImageType::IndexType index;
+  VectorImageType::IndexType index{};
   auto                       value = itk::MakeFilled<VectorImageType::PixelType>(1.0);
-  index.Fill(0);
   phiLattice->SetPixel(index, value);
   index.Fill(3);
   value.Fill(1.0);
diff --git a/Modules/Filtering/Path/include/itkChainCodeToFourierSeriesPathFilter.hxx b/Modules/Filtering/Path/include/itkChainCodeToFourierSeriesPathFilter.hxx
@@ -64,10 +64,8 @@ ChainCodeToFourierSeriesPathFilter<TInputChainCodePath, TOutputFourierSeriesPath
   for (unsigned int n = 0; n < numHarmonics; ++n)
   {
     auto       index = inputPtr->GetStart();
-    VectorType cosCoefficient;
-    cosCoefficient.Fill(0.0);
-    VectorType sinCoefficient;
-    sinCoefficient.Fill(0.0);
+    VectorType cosCoefficient{};
+    VectorType sinCoefficient{};
 
     for (InputPathInputType step = 0; step < numSteps; ++step)
     {
diff --git a/Modules/Filtering/Path/include/itkFourierSeriesPath.hxx b/Modules/Filtering/Path/include/itkFourierSeriesPath.hxx
@@ -27,9 +27,8 @@ auto
 FourierSeriesPath<VDimension>::Evaluate(const InputType & input) const -> OutputType
 {
   InputType  theta;
-  OutputType output;
+  OutputType output{};
   const int  numHarmonics = m_CosCoefficients->Size();
-  output.Fill(0);
 
   const double PI = 4.0 * std::atan(1.0);
 
@@ -54,9 +53,8 @@ auto
 FourierSeriesPath<VDimension>::EvaluateDerivative(const InputType & input) const -> VectorType
 {
   InputType  theta;
-  VectorType output;
+  VectorType output{};
   const int  numHarmonics = m_CosCoefficients->Size();
-  output.Fill(0);
 
   const double PI = 4.0 * std::atan(1.0);
 
diff --git a/Modules/Filtering/QuadEdgeMeshFiltering/include/itkSmoothingQuadEdgeMeshFilter.hxx b/Modules/Filtering/QuadEdgeMeshFiltering/include/itkSmoothingQuadEdgeMeshFilter.hxx
@@ -93,10 +93,9 @@ SmoothingQuadEdgeMeshFilter<TInputMesh, TOutputMesh>::GenerateData()
       if (qe != nullptr)
       {
         OutputPointType  r = p;
-        OutputVectorType v;
-        v.Fill(0.0);
-        OutputQEType *  qe_it = qe;
-        OutputCoordType sum_coeff = 0.;
+        OutputVectorType v{};
+        OutputQEType *   qe_it = qe;
+        OutputCoordType  sum_coeff = 0.;
         do
         {
           OutputPointType q = mesh->GetPoint(qe_it->GetDestination());
diff --git a/Modules/IO/NRRD/test/itkNrrdLocaleTest.cxx b/Modules/IO/NRRD/test/itkNrrdLocaleTest.cxx
@@ -45,8 +45,7 @@ itkNrrdLocaleTest(int argc, char * argv[])
 
   auto size = itk::MakeFilled<ImageType::SizeType>(16);
 
-  ImageType::IndexType start;
-  start.Fill(0);
+  ImageType::IndexType start{};
 
   ImageType::RegionType region(start, size);
   image->SetRegions(region);
diff --git a/Modules/Numerics/Statistics/test/itkImageToListSampleAdaptorTest2.cxx b/Modules/Numerics/Statistics/test/itkImageToListSampleAdaptorTest2.cxx
@@ -34,10 +34,9 @@ itkImageToListSampleAdaptorTest2(int, char *[])
 
   auto image = ImageType::New();
 
-  ImageType::IndexType start;
+  ImageType::IndexType start{};
   auto                 size = itk::MakeFilled<ImageType::SizeType>(10);
 
-  start.Fill(0);
 
   const ImageType::RegionType region(start, size);
   image->SetRegions(region);
@@ -121,10 +120,9 @@ itkImageToListSampleAdaptorTest2(int, char *[])
 
   auto vImage = VariableLengthImageType::New();
 
-  VariableLengthImageType::IndexType vStart;
+  VariableLengthImageType::IndexType vStart{};
   auto                               vSize = itk::MakeFilled<VariableLengthImageType::SizeType>(10);
 
-  vStart.Fill(0);
 
   const VariableLengthImageType::RegionType vRegion(vStart, vSize);
   vImage->SetRegions(vRegion);
@@ -196,10 +194,9 @@ itkImageToListSampleAdaptorTest2(int, char *[])
 
   auto rgbImage = RGBImageType::New();
 
-  RGBImageType::IndexType rgbStart;
+  RGBImageType::IndexType rgbStart{};
   auto                    rgbSize = itk::MakeFilled<RGBImageType::SizeType>(10);
 
-  rgbStart.Fill(0);
 
   const RGBImageType::RegionType rgbRegion(rgbStart, rgbSize);
   rgbImage->SetRegions(rgbRegion);
diff --git a/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest.cxx b/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest.cxx
@@ -35,10 +35,9 @@ CreateImage()
 {
   auto image = ImageType::New();
 
-  ImageType::IndexType start;
+  ImageType::IndexType start{};
   ImageType::SizeType  size;
 
-  start.Fill(0);
 
   size[0] = 10;
   size[1] = 10;
@@ -64,10 +63,9 @@ static MaskImageType::Pointer
 CreateMaskImage()
 {
   auto                     image = MaskImageType::New();
-  MaskImageType::IndexType start;
+  MaskImageType::IndexType start{};
   auto                     size = itk::MakeFilled<MaskImageType::SizeType>(10);
 
-  start.Fill(0);
 
   const MaskImageType::RegionType region(start, size);
   image->SetRegions(region);
diff --git a/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest2.cxx b/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest2.cxx
@@ -36,10 +36,9 @@ itkImageToListSampleFilterTest2(int, char *[])
   using MaskImageType = itk::Image<unsigned char, ImageDimension>;
 
   auto                 image = ImageType::New();
-  ImageType::IndexType start;
+  ImageType::IndexType start{};
   auto                 size = itk::MakeFilled<ImageType::SizeType>(10);
 
-  start.Fill(0);
 
   const ImageType::RegionType region(start, size);
   image->SetRegions(region);
diff --git a/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest3.cxx b/Modules/Numerics/Statistics/test/itkImageToListSampleFilterTest3.cxx
@@ -41,10 +41,9 @@ itkImageToListSampleFilterTest3(int, char *[])
 
   image->SetNumberOfComponentsPerPixel(MeasurementVectorSize);
 
-  ImageType::IndexType start;
+  ImageType::IndexType start{};
   auto                 size = itk::MakeFilled<ImageType::SizeType>(10);
 
-  start.Fill(0);
 
   const ImageType::RegionType region(start, size);
   image->SetRegions(region);
diff --git a/Modules/Numerics/Statistics/test/itkJointDomainImageToListSampleAdaptorTest.cxx b/Modules/Numerics/Statistics/test/itkJointDomainImageToListSampleAdaptorTest.cxx
@@ -34,10 +34,9 @@ itkJointDomainImageToListSampleAdaptorTest(int, char *[])
 
   auto image = ImageType::New();
 
-  ImageType::IndexType start;
+  ImageType::IndexType start{};
   auto                 size = itk::MakeFilled<ImageType::SizeType>(10);
 
-  start.Fill(0);
 
   const unsigned long         totalSize = size[0] * size[1] * size[2];
   const ImageType::RegionType region(start, size);
diff --git a/Modules/Registration/Common/include/itkLandmarkBasedTransformInitializer.hxx b/Modules/Registration/Common/include/itkLandmarkBasedTransformInitializer.hxx
@@ -390,11 +390,9 @@ LandmarkBasedTransformInitializer<TTransform, TFixedImage, TMovingImage>::Intern
     auto fixedItr = this->m_FixedLandmarks.begin();
     auto movingItr = this->m_MovingLandmarks.begin();
 
-    VectorType fixedCentered;
-    VectorType movingCentered;
+    VectorType fixedCentered{};
+    VectorType movingCentered{};
 
-    fixedCentered.Fill(0.0);
-    movingCentered.Fill(0.0);
 
     itkDebugStatement(int ii = 0);
 
@@ -525,11 +523,9 @@ LandmarkBasedTransformInitializer<TTransform, TFixedImage, TMovingImage>::Intern
     auto fixedItr = this->m_FixedLandmarks.begin();
     auto movingItr = this->m_MovingLandmarks.begin();
 
-    VectorType fixedCentered;
-    VectorType movingCentered;
+    VectorType fixedCentered{};
+    VectorType movingCentered{};
 
-    fixedCentered.Fill(0.0);
-    movingCentered.Fill(0.0);
 
     itkDebugStatement(int ii = 0);
 
@@ -687,11 +683,9 @@ LandmarkBasedTransformInitializer<TTransform, TFixedImage, TMovingImage>::Intern
     fixedItr = this->m_FixedLandmarks.begin();
     movingItr = this->m_MovingLandmarks.begin();
 
-    VectorType fixedCentered;
-    VectorType movingCentered;
+    VectorType fixedCentered{};
+    VectorType movingCentered{};
 
-    fixedCentered.Fill(0.0);
-    movingCentered.Fill(0.0);
 
     itkDebugStatement(int ii = 0);
     double s_dot = 0;
diff --git a/Modules/Registration/Common/test/itkBSplineExponentialDiffeomorphicTransformParametersAdaptorTest.cxx b/Modules/Registration/Common/test/itkBSplineExponentialDiffeomorphicTransformParametersAdaptorTest.cxx
@@ -98,9 +98,8 @@ itkBSplineExponentialDiffeomorphicTransformParametersAdaptorTest(int, char *[])
   adaptor->SetRequiredDirection(displacementField->GetDirection());
 
   auto                   updateMeshSize = itk::MakeFilled<AdaptorType::ArrayType>(10);
-  AdaptorType::ArrayType velocityMeshSize;
+  AdaptorType::ArrayType velocityMeshSize{};
 
-  velocityMeshSize.Fill(0);
 
   adaptor->SetMeshSizeForTheUpdateField(updateMeshSize);
   adaptor->SetMeshSizeForTheConstantVelocityField(velocityMeshSize);
diff --git a/Modules/Registration/Common/test/itkBSplineSmoothingOnUpdateDisplacementFieldTransformParametersAdaptorTest.cxx b/Modules/Registration/Common/test/itkBSplineSmoothingOnUpdateDisplacementFieldTransformParametersAdaptorTest.cxx
@@ -104,9 +104,8 @@ itkBSplineSmoothingOnUpdateDisplacementFieldTransformParametersAdaptorTest(int,
   adaptor->SetRequiredDirection(displacementField->GetDirection());
 
   auto                   updateMeshSize = itk::MakeFilled<AdaptorType::ArrayType>(10);
-  AdaptorType::ArrayType totalMeshSize;
+  AdaptorType::ArrayType totalMeshSize{};
 
-  totalMeshSize.Fill(0);
 
   adaptor->SetMeshSizeForTheUpdateField(updateMeshSize);
   adaptor->SetMeshSizeForTheTotalField(totalMeshSize);
diff --git a/Modules/Registration/RegistrationMethodsv4/test/itkTimeVaryingBSplineVelocityFieldPointSetRegistrationTest.cxx b/Modules/Registration/RegistrationMethodsv4/test/itkTimeVaryingBSplineVelocityFieldPointSetRegistrationTest.cxx
@@ -148,13 +148,12 @@ itkTimeVaryingBSplineVelocityFieldPointSetRegistrationTest(int itkNotUsed(argc),
   // Determine the parameters (size, spacing, etc) for the time-varying velocity field
 
   auto transformDomainMeshSize = itk::MakeFilled<TimeVaryingVelocityFieldControlPointLatticeType::SizeType>(4);
-  TimeVaryingVelocityFieldControlPointLatticeType::PointType transformDomainOrigin;
+  TimeVaryingVelocityFieldControlPointLatticeType::PointType transformDomainOrigin{};
   auto transformDomainSpacing = itk::MakeFilled<TimeVaryingVelocityFieldControlPointLatticeType::SpacingType>(1.0);
   auto transformDomainSize = itk::MakeFilled<TimeVaryingVelocityFieldControlPointLatticeType::SizeType>(10);
   TimeVaryingVelocityFieldControlPointLatticeType::DirectionType transformDomainDirection;
 
   transformDomainDirection.SetIdentity();
-  transformDomainOrigin.Fill(0.0);
 
   for (unsigned int i = 0; i < Dimension; ++i)
   {
@@ -189,13 +188,12 @@ itkTimeVaryingBSplineVelocityFieldPointSetRegistrationTest(int itkNotUsed(argc),
   velocityFieldLattice->Allocate();
   velocityFieldLattice->FillBuffer(zeroVector);
 
-  TransformType::VelocityFieldPointType velocityFieldOrigin;
+  TransformType::VelocityFieldPointType velocityFieldOrigin{};
   auto velocityFieldSpacing = itk::MakeFilled<TransformType::VelocityFieldSpacingType>(1.0);
   auto velocityFieldSize =
     itk::MakeFilled<TransformType::VelocityFieldSizeType>(velocityFieldRegistration->GetNumberOfTimePointSamples());
   TransformType::VelocityFieldDirectionType velocityFieldDirection;
 
-  velocityFieldOrigin.Fill(0.0);
   velocityFieldDirection.SetIdentity();
 
   for (unsigned int i = 0; i < Dimension; ++i)
diff --git a/Modules/Segmentation/Classifiers/test/itkImageClassifierFilterTest.cxx b/Modules/Segmentation/Classifiers/test/itkImageClassifierFilterTest.cxx
@@ -57,10 +57,9 @@ itkImageClassifierFilterTest(int argc, char * argv[])
 
   auto image = InputImageType::New();
 
-  InputImageType::IndexType start;
+  InputImageType::IndexType start{};
   auto                      size = itk::MakeFilled<InputImageType::SizeType>(512);
 
-  start.Fill(0);
 
   const InputImageType::RegionType region(start, size);
   image->SetRegions(region);
diff --git a/Modules/Segmentation/KLMRegionGrowing/include/itkKLMRegionGrowImageFilter.hxx b/Modules/Segmentation/KLMRegionGrowing/include/itkKLMRegionGrowImageFilter.hxx
@@ -407,10 +407,8 @@ KLMRegionGrowImageFilter<TInputImage, TOutputImage>::InitializeKLM()
     }
 
     // index to atomic region1 and atomic region2
-    InputImageIndexType indexRegion1;
-    InputImageIndexType indexRegion2;
-    indexRegion1.Fill(0);
-    indexRegion2.Fill(0);
+    InputImageIndexType indexRegion1{};
+    InputImageIndexType indexRegion2{};
     indexRegion2[idim]++;
 
     for (unsigned int iborder = 0; iborder < numBorderThisDim; ++iborder)
diff --git a/Modules/Video/Core/include/itkVideoStream.h b/Modules/Video/Core/include/itkVideoStream.h
diff --git a/Modules/Video/Core/test/itkVideoStreamTest.cxx b/Modules/Video/Core/test/itkVideoStreamTest.cxx

Original file line number	Diff line number	Diff line change
`@@ -64,10 +64,8 @@ ChainCodeToFourierSeriesPathFilter<TInputChainCodePath, TOutputFourierSeriesPath`
`64`	`64`	`for (unsigned int n = 0; n < numHarmonics; ++n)`
`65`	`65`	`{`
`66`	`66`	`auto index = inputPtr->GetStart();`
`67`		`- VectorType cosCoefficient;`
`68`		`- cosCoefficient.Fill(0.0);`
`69`		`- VectorType sinCoefficient;`
`70`		`- sinCoefficient.Fill(0.0);`
	`67`	`+ VectorType cosCoefficient{};`
	`68`	`+ VectorType sinCoefficient{};`
`71`	`69`
`72`	`70`	`for (InputPathInputType step = 0; step < numSteps; ++step)`
`73`	`71`	`{`