STYLE: Remove ITKv4 compatibility support

ITKv4 compile time API support is removed.

CMake/ITKConfig.cmake.in

@@ -26,9 +26,6 @@ set(ITK_VERSION_MAJOR "@ITK_VERSION_MAJOR@")
 set(ITK_VERSION_MINOR "@ITK_VERSION_MINOR@")
 set(ITK_VERSION_PATCH "@ITK_VERSION_PATCH@")
 
-# If ITK was built with version 4 compatibility features.
-set(ITKV4_COMPATIBILITY "@ITKV4_COMPATIBILITY@")
-
 # Remove all legacy code completely.
 set(ITK_LEGACY_REMOVE "@ITK_LEGACY_REMOVE@")
 

CMakeLists.txt

@@ -325,20 +325,16 @@ cmake_dependent_option(
   OFF
   "NOT ITK_LEGACY_REMOVE"
   OFF)
-# The disabling of legacy code, and the ITKv4 compatibility option can not both be
-# requested. If removal of legacy code is requested, then ITKV4_COMPATIBILITY must
-# be off.
-cmake_dependent_option(
-  ITKV4_COMPATIBILITY
-  "Enable LEGACY compatibility with ITK4.x when possible."
-  OFF
-  "NOT ITK_LEGACY_REMOVE"
-  OFF)
+
 mark_as_advanced(
   ITK_LEGACY_SILENT
   ITK_LEGACY_REMOVE
   ITK_FUTURE_LEGACY_REMOVE
-  ITKV4_COMPATIBILITY)
+  )
+
+if(ITKV4_COMPATIBILITY)
+  message(FATAL_ERROR "ITKV4_COMPATIBILITY is removed starting in ITK version 4.0, this option is no longer valid.")
+endif()
 
 if(ITKV3_COMPATIBILITY)
   message(FATAL_ERROR "ITKV3_COMPATIBILITY is removed starting in ITK version 5.0, this option is no longer valid.")

Documentation/docs/migration_guides/itk_6_migration_guide.md

@@ -22,6 +22,10 @@ deprecations and API changes. The new behavior is activated by setting
 `ITK_LEGACY_REMOVE` to `ON`. By default, compatibility with v5 is retained
 (`ITK_LEGACY_REMOVE=OFF`).
 
+Remove support for ITKv4 interfaces
+-----------------------------------
+
+ITKV4_COMPATIBILITY is no longer a supported option.
 
 Require modern C++ language feature use
 ---------------------------------------

Modules/Compatibility/Deprecated/include/itkImageTransformer.hxx

@@ -323,20 +323,6 @@ ImageTransformer<TInputImage>::ThreaderCallback(void * arg)
   if (threadId < total)
   {
     str->Filter->ThreadedGenerateData(splitRegion, threadId);
-#if defined(ITKV4_COMPATIBILITY)
-    if (str->Filter->GetAbortGenerateData())
-    {
-      std::string    msg;
-      ProcessAborted e(__FILE__, __LINE__);
-      msg += "Object " + std::string(str->Filter->GetNameOfClass()) + ": AbortGenerateData was set!";
-      e.SetDescription(msg);
-      throw e;
-    }
-    else if (str->Filter->GetProgress() == 0.0f) // progress was not set after at least the first chunk finished
-    {
-      str->Filter->UpdateProgress(static_cast<float>(threadId + 1) / total); // this will be the only progress update
-    }
-#endif
   }
   // else
   //   {

Modules/Compatibility/Deprecated/itk-module.cmake

@@ -2,9 +2,6 @@ set(DOCUMENTATION "This is a collection of classes that are intended to be
 removed from the toolkit.")
 
 set(ITKDeprecatedOnByDefault EXCLUDE_FROM_DEFAULT)
-if(ITKV4_COMPATIBILITY)
-  set(ITKDeprecatedOnByDefault "")
-endif()
 
 itk_module(
   ITKDeprecated

Modules/Core/Common/include/itkImageSource.hxx

@@ -45,11 +45,7 @@ ImageSource<TOutputImage>::ImageSource()
   this->ProcessObject::SetNumberOfRequiredOutputs(1);
   this->ProcessObject::SetNthOutput(0, output.GetPointer());
 
-#if defined(ITKV4_COMPATIBILITY)
-  m_DynamicMultiThreading = false;
-#else
   m_DynamicMultiThreading = true;
-#endif
 
   // Set the default behavior of an image source to NOT release its
   // output bulk data prior to GenerateData() in case that bulk data
@@ -287,21 +283,6 @@ ImageSource<TOutputImage>::ThreaderCallback(void * arg)
   if (workUnitID < total)
   {
     str->Filter->ThreadedGenerateData(splitRegion, workUnitID);
-#if defined(ITKV4_COMPATIBILITY)
-    if (str->Filter->GetAbortGenerateData())
-    {
-      std::string    msg;
-      ProcessAborted e(__FILE__, __LINE__);
-      msg += "Object " + std::string(str->Filter->GetNameOfClass()) + ": AbortGenerateData was set!";
-      e.SetDescription(msg);
-      throw e;
-    }
-    else if (!str->Filter->GetDynamicMultiThreading() // progress reporting is not done in MultiThreaders
-             && str->Filter->GetProgress() == 0.0f) // and progress was not set after at least the first chunk finished
-    {
-      str->Filter->UpdateProgress(static_cast<float>(workUnitID + 1) / total); // this will be the only progress update
-    }
-#endif
   }
   // else don't use this thread. Threads were not split conveniently.
   return ITK_THREAD_RETURN_DEFAULT_VALUE;

Modules/Core/Common/include/itkMacro.h

@@ -1359,11 +1359,7 @@ compilers.
  * classes can be achieved with defining ITKV4_COMPATIBILITY. Code
  * should be migrated to no longer rely on the old virtual interface.
  */
-#if defined(ITKV4_COMPATIBILITY)
-#  define ITK_ITERATOR_VIRTUAL virtual
-#  define ITK_ITERATOR_OVERRIDE override
-#  define ITK_ITERATOR_FINAL
-#elif !defined(ITK_LEGACY_REMOVE)
+#if !defined(ITK_LEGACY_REMOVE)
 #  define ITK_ITERATOR_VIRTUAL virtual
 #  define ITK_ITERATOR_OVERRIDE override
 #  define ITK_ITERATOR_FINAL final

Modules/Core/Common/include/itkProcessObject.h

@@ -494,12 +494,6 @@ class ITKCommon_EXPORT ProcessObject : public Object
   itkSetClampMacro(NumberOfWorkUnits, ThreadIdType, 1, ITK_MAX_THREADS);
   itkGetConstReferenceMacro(NumberOfWorkUnits, ThreadIdType);
 
-#if !defined(ITK_LEGACY_REMOVE) || defined(ITKV4_COMPATIBILITY)
-  itkLegacyMacro(void SetNumberOfThreads(ThreadIdType count)) { this->SetNumberOfWorkUnits(count); }
-
-  itkLegacyMacro(ThreadIdType GetNumberOfThreads() const) { return this->GetNumberOfWorkUnits(); }
-#endif // !ITK_LEGACY_REMOVE
-
   /** Return the multithreader used by this class. */
   MultiThreaderType *
   GetMultiThreader() const

Modules/Core/Common/src/itkConfigure.h.in

@@ -71,7 +71,6 @@
 #endif
 #cmakedefine ITK_DYNAMIC_LOADING
 
-#cmakedefine ITKV4_COMPATIBILITY
 #cmakedefine ITK_LEGACY_REMOVE
 #cmakedefine ITK_LEGACY_SILENT
 #cmakedefine ITK_FUTURE_LEGACY_REMOVE

Modules/Core/Common/src/itkPoolMultiThreader.cxx

@@ -86,12 +86,6 @@ PoolMultiThreader::PoolMultiThreader()
   }
 
   ThreadIdType defaultThreads = std::max(1u, GetGlobalDefaultNumberOfThreads());
-#if !defined(ITKV4_COMPATIBILITY)
-  if (defaultThreads > 1) // one work unit for only one thread
-  {
-    defaultThreads *= 4;
-  }
-#endif
   m_NumberOfWorkUnits = std::min<ThreadIdType>(ITK_MAX_THREADS, defaultThreads);
   m_MaximumNumberOfThreads = m_ThreadPool->GetMaximumNumberOfThreads();
 }

Modules/Core/Common/src/itkTBBMultiThreader.cxx

@@ -47,14 +47,10 @@ namespace itk
 TBBMultiThreader::TBBMultiThreader()
 {
   ThreadIdType defaultThreads = std::max(1u, GetGlobalDefaultNumberOfThreads());
-#if defined(ITKV4_COMPATIBILITY)
-  m_NumberOfWorkUnits = defaultThreads;
-#else
   if (defaultThreads > 1) // one work unit for only one thread
   {
     m_NumberOfWorkUnits = 16 * defaultThreads;
   }
-#endif
 }
 
 TBBMultiThreader::~TBBMultiThreader() = default;

Modules/Core/ImageFunction/include/itkInterpolateImageFunction.h

@@ -127,28 +127,13 @@ class ITK_TEMPLATE_EXPORT InterpolateImageFunction
     return (static_cast<RealType>(this->GetInputImage()->GetPixel(index)));
   }
 
-/** Get the radius required for interpolation.
- *
- * This defines the number of surrounding pixels required to interpolate at
- * a given point.
- */
-#if defined(ITKV4_COMPATIBILITY)
-  virtual SizeType
-  GetRadius() const
-  {
-    // if ITKv4 compatibility is enabled then set the radius to the
-    // largest by default.
-    const InputImageType * input = this->GetInputImage();
-    if (!input)
-    {
-      itkExceptionMacro("Input image required!");
-    }
-    return input->GetLargestPossibleRegion().GetSize();
-  }
-#else
+  /** Get the radius required for interpolation.
+   *
+   * This defines the number of surrounding pixels required to interpolate at
+   * a given point.
+   */
   virtual SizeType
   GetRadius() const = 0;
-#endif
 
 protected:
   InterpolateImageFunction() = default;

Modules/Filtering/Smoothing/include/itkBoxMeanImageFilter.hxx

@@ -64,32 +64,9 @@ BoxMeanImageFilter<TInputImage, TOutputImage>::DynamicThreadedGenerateData(
   accImage->SetRegions(accumRegion);
   accImage->Allocate();
 
-#if defined(ITKV4_COMPATIBILITY)
-  // Dummy reporter for compatibility
-  ProgressReporter progress(this, 1, 2 * accumRegion.GetNumberOfPixels());
-#endif
-
-  BoxAccumulateFunction<TInputImage, AccumImageType>(inputImage,
-                                                     accImage,
-                                                     accumRegion,
-                                                     accumRegion
-#if defined(ITKV4_COMPATIBILITY)
-                                                     ,
-                                                     progress);
-#else
-  );
-#endif
-  BoxMeanCalculatorFunction<AccumImageType, TOutputImage>(accImage.GetPointer(),
-                                                          outputImage,
-                                                          accumRegion,
-                                                          outputRegionForThread,
-                                                          this->GetRadius()
-#if defined(ITKV4_COMPATIBILITY)
-                                                            ,
-                                                          progress);
-#else
-  );
-#endif
+  BoxAccumulateFunction<TInputImage, AccumImageType>(inputImage, accImage, accumRegion, accumRegion);
+  BoxMeanCalculatorFunction<AccumImageType, TOutputImage>(
+    accImage.GetPointer(), outputImage, accumRegion, outputRegionForThread, this->GetRadius());
 }
 } // end namespace itk
 #endif

Modules/Filtering/Smoothing/include/itkBoxSigmaImageFilter.hxx

@@ -66,32 +66,9 @@ BoxSigmaImageFilter<TInputImage, TOutputImage>::DynamicThreadedGenerateData(
   accImage->SetRegions(accumRegion);
   accImage->Allocate();
 
-#if defined(ITKV4_COMPATIBILITY)
-  // Dummy reporter for compatibility
-  ProgressReporter progress(this, 1, 2 * accumRegion.GetNumberOfPixels());
-#endif
-
-  BoxSquareAccumulateFunction<TInputImage, AccumImageType>(inputImage,
-                                                           accImage,
-                                                           accumRegion,
-                                                           accumRegion
-#if defined(ITKV4_COMPATIBILITY)
-                                                           ,
-                                                           progress);
-#else
-  );
-#endif
-  BoxSigmaCalculatorFunction<AccumImageType, TOutputImage>(accImage,
-                                                           outputImage,
-                                                           accumRegion,
-                                                           outputRegionForThread,
-                                                           this->GetRadius()
-#if defined(ITKV4_COMPATIBILITY)
-                                                             ,
-                                                           progress);
-#else
-  );
-#endif
+  BoxSquareAccumulateFunction<TInputImage, AccumImageType>(inputImage, accImage, accumRegion, accumRegion);
+  BoxSigmaCalculatorFunction<AccumImageType, TOutputImage>(
+    accImage, outputImage, accumRegion, outputRegionForThread, this->GetRadius());
 }
 } // end namespace itk
 #endif