Merge pull request #467 from blowekamp/use_itk_fetchcontent

Use FetchContent to build ITK

Author: blowekamp

.github/workflows/build-test-publish.yml

@@ -64,26 +64,6 @@ jobs:
           key: externaldata-v1-${{ hashFiles('Ex/src/**/*.cid') }}
           restore-keys: |
             externaldata-v1-
-
-      - name: Build ITK
-        if: matrix.os != 'windows-2022'
-        run: |
-          cd ..
-          mkdir ITK-build
-          cd ITK-build
-          cmake -DCMAKE_C_COMPILER:FILEPATH="${{ matrix.c-compiler }}" -DBUILD_SHARED_LIBS:BOOL=ON -DCMAKE_CXX_COMPILER="${{ matrix.cxx-compiler }}" -DCMAKE_BUILD_TYPE:STRING=${{ matrix.cmake-build-type }} -DBUILD_TESTING:BOOL=OFF -GNinja ../ITK
-          ninja
-      - name: Build ITK
-        if: matrix.os == 'windows-2022'
-        run: |
-          cd ..
-          mkdir ITK-build
-          cd ITK-build
-          call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-          cmake -DCMAKE_C_COMPILER:FILEPATH="${{ matrix.c-compiler }}" -DBUILD_SHARED_LIBS:BOOL=OFF -DCMAKE_CXX_COMPILER="${{ matrix.cxx-compiler }}" -DCMAKE_BUILD_TYPE:STRING=${{ matrix.cmake-build-type }} -DBUILD_TESTING:BOOL=OFF -GNinja ../ITK
-          ninja
-        shell: cmd
-
       - name: Fetch CTest driver script
         run: |
           curl -L https://raw.githubusercontent.com/InsightSoftwareConsortium/ITK/dashboard/itk_common.cmake -O

CMake/ITKFetchContent.cmake

@@ -0,0 +1,59 @@
+#-----------------------------------------------------------------------------
+# Get and build ITK using FetchContent
+
+include(FetchContent)
+
+# Set ITK Git repository and tag
+set(ITK_GIT_REPOSITORY "https://github.com/InsightSoftwareConsortium/ITK.git")
+set(ITK_GIT_TAG "main")
+
+if(NOT DEFINED ITK_BUILD_DEFAULT_MODULES)
+  set(ITK_BUILD_DEFAULT_MODULES ON)
+endif()
+
+# Configure ITK-specific options that need to be set before FetchContent_Declare
+if(NOT BUILD_SHARED_LIBS)
+  set(CMAKE_C_VISIBILITY_PRESET "hidden")
+  set(CMAKE_CXX_VISIBILITY_PRESET "hidden")
+  set(ITK_TEMPLATE_VISIBILITY_DEFAULT OFF)
+endif()
+
+set(Module_ITKReview ON CACHE INTERNAL "")
+
+# Set ITK build options
+set(ITK_USE_KWSTYLE OFF)
+set(BUILD_TESTING OFF)
+set(BUILD_EXAMPLES OFF)
+
+FetchContent_Declare(
+  ITK
+  GIT_REPOSITORY "${ITK_GIT_REPOSITORY}"
+  GIT_TAG "${ITK_GIT_TAG}"
+  EXCLUDE_FROM_ALL
+  FIND_PACKAGE_ARGS
+    NAMES
+    ITK
+)
+
+FetchContent_MakeAvailable(ITK)
+
+# Check if FetchContent used find_package() or fetched from source
+FetchContent_GetProperties(ITK)
+if(ITK_SOURCE_DIR)
+  message(STATUS "ITK fetched from repository and built from source")
+  message(STATUS "  Source directory: ${ITK_SOURCE_DIR}")
+  message(STATUS "  Binary directory: ${ITK_BINARY_DIR}")
+  set(ITK_DIR "${ITK_BINARY_DIR}")
+
+  include(${ITK_DIR}/ITKConfig.cmake)
+elseif(DEFINED ITK_FOUND)
+  message(STATUS "ITK found via find_package()")
+  # ITK_DIR should already be set by find_package()
+else()
+  message(FATAL_ERROR "ITK configuration failed - no targets available")
+endif()
+
+# These ITK options conflict with ITKSphinxExamples build options.
+# Allow ITKSphinxExamples' cache variables to be respected.
+unset(BUILD_TESTING)
+unset(BUILD_EXAMPLES)

CMakeLists.txt

@@ -79,8 +79,9 @@ endif()
 #Optional if we are building as an ITK module, these variables will be pre-defined
 if(NOT ITK_VERSION)
   # To get the ITK version information from external package when building
-  # stand alone, ITK is required.
-  find_package(ITK 5.4.2 REQUIRED)
+  # stand alone, ITK is required. ITK can be provided via ITK_DIR or fetched
+  # from source using FetchContent.
+  include(${CMAKE_CURRENT_SOURCE_DIR}/CMake/ITKFetchContent.cmake)
 endif()
 set(ITKSphinxExamples_VERSION_MAJOR ${ITK_VERSION_MAJOR})
 set(ITKSphinxExamples_VERSION_MINOR ${ITK_VERSION_MINOR})
@@ -308,7 +309,8 @@ configure_file("${ITKSphinxExamples_SOURCE_DIR}/Utilities/CreateNewExample.py.in
 
 # Build the example executables?
 option(BUILD_EXECUTABLES "Build the example executables." ON)
-if(COMMAND itk_module_impl)
+# Use itk-module (set by ITK's module system) to detect if we are building as an ITK module or stand alone.
+if(itk-module)
   itk_module_impl()
 else()
   if(BUILD_EXECUTABLES)

Formatting/conf.py.in

@@ -90,7 +90,7 @@ release = '@ITKSphinxExamples_RELEASE_VERSION@'
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ['Utilities', 'html']
+exclude_patterns = ['Utilities', 'html', '_deps']
 
 # The reST default role (used for this markup: `text`) to use for all documents.
 #default_role = None

Superbuild/External-ITK.cmake

@@ -29,15 +29,13 @@ else()
 endif()
 
 set(ITKSphinxExamples_DEPENDENCIES )
-set(ITK_DEPENDENCIES )
 
 option(ITKSphinxExamples_USE_VTK "Add VTK to the superbuild." OFF)
 
 option(ITKSphinxExamples_USE_OpenCV "Add OpenCV to the superbuild" OFF)
 if(NOT OpenCV_DIR AND ITKSphinxExamples_USE_OpenCV)
   include(${CMAKE_SOURCE_DIR}/External-OpenCV.cmake)
   list(APPEND ITKSphinxExamples_DEPENDENCIES OpenCV)
-  list(APPEND ITK_DEPENDENCIES OpenCV)
 endif()
 
 
@@ -55,13 +53,11 @@ endif()
 if(NOT VTK_DIR AND ITKSphinxExamples_USE_VTK)
   include(${CMAKE_SOURCE_DIR}/External-VTK.cmake)
   list(APPEND ITKSphinxExamples_DEPENDENCIES VTK)
-  list(APPEND ITK_DEPENDENCIES VTK)
 endif()
 
-if(NOT ITK_DIR)
-  include(${CMAKE_SOURCE_DIR}/External-ITK.cmake)
-  list(APPEND ITKSphinxExamples_DEPENDENCIES ITK)
-endif()
+# ITK is no longer fetched by the Superbuild. It is acquired via FetchContent
+# in the root CMakeLists.txt. Pass ITK_DIR through if provided by the user
+# so the inner build can use a pre-built ITK via find_package.
 
 option(BUILD_DOCUMENTATION "Build documentation" OFF)
 set(_build_doc_args)
@@ -108,7 +104,7 @@ ExternalProject_Add(ITKSphinxExamples
     ${_build_doc_args}
     ${_python_args}
     -DBUILD_SHARED_LIBS:BOOL=FALSE
-     # ITK
+    # ITK — pass through ITK_DIR if provided, otherwise FetchContent handles it
     -DITK_DIR:PATH=${ITK_DIR}
     -DBUILD_TESTING:BOOL=${BUILD_TESTING}
     -DBUILD_DOCUMENTATION:BOOL=${BUILD_DOCUMENTATION}

Superbuild/Superbuild.cmake

@@ -9,10 +9,14 @@ find_package( ITK REQUIRED
   ITKMathematicalMorphology
   ITKIOPNG
   )
-include( ${ITK_USE_FILE} )
 
 add_executable( DilateUsingFunctionalGrayscale Code.cxx )
-target_link_libraries( DilateUsingFunctionalGrayscale ${ITK_LIBRARIES} )
+target_link_libraries(${PROJECT_NAME}
+  PRIVATE
+    ITK::ITKImageIO
+    ITK::ITKCommonModule
+    ITK::ITKMathematicalMorphologyModule
+)
 
 install( TARGETS DilateUsingFunctionalGrayscale
   DESTINATION bin/ITKSphinxExamples/Filtering/MathematicalMorphology