Building for Apple Platforms

build_xcframework.py creates an xcframework supporting a variety of Apple platforms.

You'll need the following to run these steps:

• MacOS 10.15 or later
• Python 3.6 or later
• CMake 3.18.5/3.19.0 or later (make sure the cmake command is available on your PATH)
• Xcode 12.2 or later (and its command line tools)

You can then run build_xcframework.py, as below:

cd ~/<my_working_directory>
python opencv/platforms/apple/build_xcframework.py --out ./build_xcframework

Grab a coffee, because you'll be here for a while. By default this builds OpenCV for 8 architectures across 4 platforms:

• iOS (--iphoneos_archs): arm64, armv7
• iOS Simulator (--iphonesimulator_archs): x86_64, arm64
• macOS (--macos_archs): x86_64, arm64
• Mac Catalyst (--catalyst_archs): x86_64, arm64

If everything's fine, you will eventually get opencv2.xcframework in the output directory.

The script has some configuration options to exclude platforms and architectures you don't want to build for. Use the --help flag for more information.

How it Works

This script generates a fat .framework for each platform you specify, and stitches them together into a .xcframework. This file can be used to support the same architecture on different platforms, which fat .frameworks don't allow. To build the intermediate .frameworks, build_xcframework.py leverages the build_framework.py scripts in the ios and osx platform folders.

Passthrough Arguments

Any arguments that aren't recognized by build_xcframework.py will be passed to the platform-specific build_framework.py scripts. The --without flag mentioned in the examples is an example of this in action. For more info, see the --help info for those scripts.

Examples

You may override the defaults by specifying a value for any of the *_archs flags. For example, if you want to build for arm64 on every platform, you can do this:

python build_xcframework.py --out somedir --iphoneos_archs arm64 --iphonesimulator_archs arm64 --macos_archs arm64 --catalyst_archs arm64

If you want to build only for certain platforms, you can supply the --build_only_specified_archs flag, which makes the script build only the archs you directly ask for. For example, to build only for Catalyst, you can do this:

python build_xcframework.py --out somedir --catalyst_archs x86_64,arm64 --build_only_specified_archs

You can also build without OpenCV functionality you don't need. You can do this by using the --without flag, which you use once per item you want to go without. For example, if you wanted to compile without video or objc, you'd can do this:

python build_xcframework.py --out somedir --without video --without objc

(if you have issues with this, try using =, e.g. --without=video --without=objc, and file an issue on GitHub.)