Install Fcitx 5 and Hangul plugin:
sudo apt install fcitx5 fcitx5-hangul
Launch im-config
, congfirm and select fcitx5
as your new default input method.
Add these lines to your /etc/profile
so you can use it with all applications:
export XMODIFIERS=@im=fcitx
export GTK_IM_MODULE=fcitx
export QT_IM_MODULE=fcitx
Make fcitx5 autostart after login:
sudo cp /usr/share/applications/org.fcitx.Fcitx5.desktop .config/autostart/
Reboot.
Launch Fcitx5 Configuration (fcitx5-congfigtool
), add the Hangul layout and change its settings how you like. You probably want to switch the layout to Romaja and disable Hanja Mode.
You can play with the settings and add other input methods like fcitx5-mozc
(Japanese input). Note that you have to restart fcitx5 to be able to select new plugins in the config tool.