This directory contains files specific to the Flutter macOS embedder. The embedder is built as a macOS framework that is linked into the target application. The framework is composed both of macOS-specific code and code shared with the iOS embedder. These can be found in:

flutter/shell/platform/darwin/common/framework

flutter/shell/platform/darwin/macos/framework

Additionally, the framework relies on utility code shared across all embedders, which is found in:

flutter/shell/platform/common

To learn more, see the Engine architecture wiki.

Building

Building all artifacts required for macOS occurs in two steps:

Host binary build: Builds tooling used by the Flutter tool to build Flutter applications targeting macOS.
macOS Target build: Builds the framework that implements the macOS Flutter embedder and exposes public API such as FlutterViewController used by Flutter applications.

Once you've prepared your environment for engine development, you can build the macOS embedder from the src/flutter directory using the following commands:

# Perform the host build.
./tools/gn --unopt
ninja -C ../out/host_debug_unopt
 
# Perform the macOS target build.
./tools/gn --unopt --mac
ninja -C ../out/mac_debug_unopt

Builds are architecture-specific, and can be controlled by specifying --mac-cpu=arm64 or --mac-cpu=x64 (default) when invoking gn.

Testing

The macOS-specific embedder tests are built as the flutter_desktop_darwin_unittests binary. Like all gtest-based test binaries, a subset of tests can be run by applying a filter such as ‘--gtest_filter='FlutterViewControllerTest.*Key*’`.

More general details on testing can be found on the Wiki.