cros_im

This project implements support for using ChromeOS IMEs over the Wayland protocols zwp_unstable_text_input_v1 and zcr_text_input_extension_unstable_v1. Googlers: See go/crostini-ime, go/crostini-ime-rollout and go/crostini-ime-tests for additional design details.

IME Support is currently limited to GTK3/4 applications (including Electron-based apps), and only Debian Bullseye/Bookworm containers are officially supported. Known issues are tracked here and bugs can be reported here.

FAQ

App support

  • Libreoffice: Please ensure the GTK3 plugin is installed: sudo apt install libreoffice-gtk3.
  • Anki: Only the Qt5 version is supported currently, and the Qt5 flag must be enabled (see below). If you manually downloaded and installed Anki, you will need to run:
sudo ln -s {/usr/lib/*/qt5,/usr/local/share/anki/lib/PyQt5/Qt5}/plugins/platforminputcontexts/libcrosplatforminputcontextplugin.so

System configuration

The #crostini-ime-support flag in chrome://flags must be enabled to fully enable Crostini IME support. It sets the env var GTK_IM_MODULE=cros globally in Crostini and configures ChromeOS to work correctly with Crostini IMEs. It is enabled by default from M116.

The Qt5 IM module can be enabled via the #crostini-qt-ime-support flag, which sets the env var QT_IM_MODULE=cros.

From M112, cros-im is installed by apt automatically.

If manually building cros_im, it is recommended to use a device on dev channel as backwards compatibility with older versions of ChromeOS is not guaranteed.

IME switching shortcuts

If you use the default keyboard shortcuts to switch IMEs, it is recommended to use the keyboard shortcut customization app to change these from Ctrl+Space to Search+Space and Ctrl+Shift+Space to Search+Ctrl+Space. Shortcuts making use of the Search key are guaranteed to work across the platform and not be consumed by applications. The shortcut customization app is enabled by default from M124 but can be manually turned on via the #enable-shortcut-customization flag in earlier versions.

It is also possible to continue using Ctrl+Space to switch IMEs but configure sommelier to allow the host compositor to handle these. Unlike using the shortcut customization app, this configuration is neither officially supported nor recommended, but steps are detailed in earlier revisions of this README if you really want to do this.

Manual build instructions

Compiling

cros_im can be compiled as follows:

git clone https://chromium.googlesource.com/chromiumos/platform2
cd platform2/vm_tools/cros_im
sudo apt install -y clang googletest libgtk-3-dev libgtkmm-3.0-dev libwayland-bin meson pkg-config xvfb weston dpkg-dev qtbase5-dev qtbase5-private-dev
meson build && cd build && ninja

Additional commands to compile with GTK4 support (from bookworm onwards):

sudo apt install -y libgtk-4-dev libgtkmm-4.0.dev
meson configure -Dbuild_gtk4=true && ninja

Testing

Automated tests can be run from a build directory with meson test. This invokes ../test/run_tests.py, which can also be run directly if needed.

The GTK3 IM module can be manually tested by setting up a custom IM module cache:

/usr/lib/*/libgtk-3-0/gtk-query-immodules-3.0 im-cros-gtk3.so > dev-immodules.cache
export GTK_IM_MODULE_FILE=$(pwd)/dev-immodules.cache

The Qt IM module cannot be easily tested prior to installation.

Installing

cros_im can be installed as follows, although this will conflict with the IM module installed by the cros-im apt package...

meson configure --prefix /usr && sudo meson install
# Manually update GTK's IM modules cache. For IM modules installed from a .deb,
# this would be automatically run by libgtk-3.0's postinst hook.
sudo /usr/lib/*/libgtk-3-0/gtk-query-immodules-3.0 --update-cache

.deb build

.deb packages can be built for Bullseye and Bookworm on supported architectures (arm64, amd64, i386) by running build-packages. The version number is the result of git rev-list --count HEAD.

These steps do not work from within Crostini as LXC containers in Crostini are unprivileged and do not have permission to run the commands required.

git clone https://chromium.googlesource.com/chromiumos/platform2
cd platform2/vm_tools/cros_im

# Build for a specific dist/arch, change args as needed.
sudo ./build-packages bookworm amd64

# Show build artifacts
ls -l *debs/