Add Apple-accelerated implementations for ImageProcessor (pytorch#20037)

Differential Revision: D106898414

Pull Request resolved: pytorch#20037

Author: metascroy

extension/image/CMakeLists.txt

@@ -6,26 +6,50 @@
 
 cmake_minimum_required(VERSION 3.19)
 
-# stb_image_resize: lightweight header-only library used by the resize step in
-# image_processor.cpp.
-include(FetchContent)
-FetchContent_Declare(
-  stb
-  GIT_REPOSITORY https://github.com/nothings/stb.git
-  GIT_TAG f0569113c93ad095470c54bf34a17b36646bbbb5
-)
-FetchContent_MakeAvailable(stb)
+if(APPLE)
+  enable_language(OBJCXX)
+  add_library(
+    extension_image image_processor_common.cpp image_processor_apple.cpp
+                    image_processor_apple_gpu.mm
+  )
+  set_source_files_properties(
+    image_processor_apple_gpu.mm PROPERTIES COMPILE_FLAGS "-fobjc-arc"
+  )
+  find_library(ACCELERATE_FRAMEWORK Accelerate REQUIRED)
+  find_library(COREGRAPHICS_FRAMEWORK CoreGraphics REQUIRED)
+  find_library(COREIMAGE_FRAMEWORK CoreImage REQUIRED)
+  find_library(COREVIDEO_FRAMEWORK CoreVideo REQUIRED)
+  find_library(FOUNDATION_FRAMEWORK Foundation REQUIRED)
+  target_link_libraries(
+    extension_image
+    PRIVATE ${ACCELERATE_FRAMEWORK} ${COREGRAPHICS_FRAMEWORK}
+            ${COREIMAGE_FRAMEWORK} ${COREVIDEO_FRAMEWORK}
+            ${FOUNDATION_FRAMEWORK}
+  )
+else()
+  # stb_image_resize: lightweight header-only library used by the resize step in
+  # image_processor.cpp. Only the portable (non-Apple) path uses stb; the Apple
+  # path resizes via vImage, so the fetch is scoped here to avoid downloading
+  # stb on Apple builds.
+  include(FetchContent)
+  FetchContent_Declare(
+    stb
+    GIT_REPOSITORY https://github.com/nothings/stb.git
+    GIT_TAG f0569113c93ad095470c54bf34a17b36646bbbb5
+  )
+  FetchContent_MakeAvailable(stb)
 
-add_library(extension_image image_processor_common.cpp image_processor.cpp)
+  add_library(extension_image image_processor_common.cpp image_processor.cpp)
 
-target_include_directories(
-  extension_image PUBLIC ${_common_include_directories}
-)
+  # stb_image_resize.h lives under deprecated/ in current stb. Private: only the
+  # .cpp uses it, not the installed public headers.
+  target_include_directories(
+    extension_image PRIVATE ${stb_SOURCE_DIR} ${stb_SOURCE_DIR}/deprecated
+  )
+endif()
 
-# stb_image_resize.h lives under deprecated/ in current stb. Private: only the
-# .cpp uses it, not the installed public headers.
 target_include_directories(
-  extension_image PRIVATE ${stb_SOURCE_DIR} ${stb_SOURCE_DIR}/deprecated
+  extension_image PUBLIC ${_common_include_directories}
 )
 
 target_link_libraries(extension_image PUBLIC executorch_core extension_tensor)
@@ -36,9 +60,16 @@ install(
   DESTINATION ${CMAKE_INSTALL_LIBDIR}
 )
 
-install(FILES image_processor.h image_processor_config.h
-        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/executorch/extension/image
-)
+if(APPLE)
+  install(FILES image_processor.h image_processor_config.h
+                image_processor_apple.h
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/executorch/extension/image
+  )
+else()
+  install(FILES image_processor.h image_processor_config.h
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/executorch/extension/image
+  )
+endif()
 
 if(BUILD_TESTING)
   add_subdirectory(test)