build: OpenCV 4 for macOS (arm64)

WORKSPACE

@@ -392,13 +392,13 @@ new_local_repository(
 
 new_local_repository(
     name = "macos_opencv",
-    build_file = "@mediapipe//third_party:opencv_macos.BUILD",
+    build_file = "@//third_party:opencv_macos.BUILD",
     path = "/usr/local",
 )
 
 new_local_repository(
     name = "macos_arm64_opencv",
-    build_file = "@mediapipe//third_party:opencv_macos.BUILD",
+    build_file = "@//third_party:opencv_macos.BUILD",
     path = "/opt/homebrew",
 )
 

third_party/opencv.BUILD

@@ -212,7 +212,7 @@ cmake(
     }) + select({
         ":dbg_cmake_static_win": ["staticlib/%sd.lib" % lib for lib in OPENCV_3RDPARTY_LIBS],
         ":cmake_static_win": ["staticlib/%s.lib" % lib for lib in OPENCV_3RDPARTY_LIBS],
-        "@cpuinfo//:macos_arm64": ["share/OpenCV/3rdparty/lib/lib%s.a" % lib for lib in OPENCV_3RDPARTY_LIBS_M1],
+        "@cpuinfo//:macos_arm64": ["lib/opencv4/3rdparty/lib%s.a" % lib for lib in OPENCV_3RDPARTY_LIBS_M1],
         "//conditions:default": ["lib/opencv4/3rdparty/lib%s.a" % lib for lib in OPENCV_3RDPARTY_LIBS],
     }),
     out_shared_libs =  [],

third_party/opencv_macos.BUILD

@@ -0,0 +1,49 @@
+# Copyright 2019 The MediaPipe Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# CHANGES:
+#  - support OpenCV 4
+
+# Description:
+#   OpenCV libraries for video/image processing on MacOS
+
+load("@bazel_skylib//lib:paths.bzl", "paths")
+
+licenses(["notice"])  # BSD license
+
+exports_files(["LICENSE"])
+
+# The path to OpenCV is a combination of the path set for "macos_opencv"
+# in the WORKSPACE file and the prefix here.
+PREFIX = "opt/opencv@4"
+
+cc_library(
+    name = "opencv",
+    srcs = glob(
+        [
+            paths.join(PREFIX, "lib/libopencv_core.dylib"),
+            paths.join(PREFIX, "lib/libopencv_calib3d.dylib"),
+            paths.join(PREFIX, "lib/libopencv_features2d.dylib"),
+            paths.join(PREFIX, "lib/libopencv_highgui.dylib"),
+            paths.join(PREFIX, "lib/libopencv_imgcodecs.dylib"),
+            paths.join(PREFIX, "lib/libopencv_imgproc.dylib"),
+            paths.join(PREFIX, "lib/libopencv_video.dylib"),
+            paths.join(PREFIX, "lib/libopencv_videoio.dylib"),
+        ],
+    ),
+    hdrs = glob([paths.join(PREFIX, "include/opencv4/opencv2/**/*.h*")]),
+    includes = [paths.join(PREFIX, "include/opencv4/")],
+    linkstatic = 1,
+    visibility = ["//visibility:public"],
+)