Input Method Usage

Fcitx Usage Guide

This document describes how to install and use the Fcitx5 input method framework on Radxa OS (Debian-based), and how to configure Chinese input.

The following packages are required:

• fcitx5
• fcitx5-chinese-addons
• fcitx5-config-qt

Install Fcitx5

Install in the desktop environment through the terminal:

radxa@zero$

sudo apt update
sudo apt install -y fcitx5 fcitx5-chinese-addons fcitx5-config-qt

Enable the Input Method (Make Applications Use Fcitx5)

Most desktop environments need to select the input method framework at the "session level". Usually you need to log out and log back in (or reboot) for it to fully take effect.

Method 1: Use im-config (Recommended)

radxa@zero$

im-config

In the pop-up interface, select fcitx5 and confirm. Then:

• Log out of the current desktop session and log back in, or
• Directly reboot the system

Method 2: Set Environment Variables (Troubleshooting / Advanced Usage)

If you encounter a situation where "Fcitx5 has started but some applications cannot input", you can check whether the following environment variables are in effect:

GTK_IM_MODULE=fcitx
QT_IM_MODULE=fcitx
XMODIFIERS=@im=fcitx

tip

The location where environment variables are loaded may differ between desktop environments (for example ~/.profile, ~/.xprofile, or desktop session settings). After modifying them you usually need to log in again.

Configure Chinese Input (fcitx5-chinese-addons)

After installing fcitx5-chinese-addons, you will get common Chinese input engines (such as Pinyin).

Open the Configuration Tool (fcitx5-config-qt)

You can start Fcitx 5 Configuration from the application menu, or start it in the terminal:

radxa@zero$

fcitx5-config-qt

Add Chinese Input Method

1. Open Fcitx 5 Configuration
2. On the Input Method page click Add
3. Search for and add Pinyin (or other Chinese input engines you need)
4. Adjust the input method order by moving them up and down

Start/Restart Fcitx5

If Fcitx5 does not start automatically, or you need to restart it to apply configuration changes:

radxa@zero$

fcitx5 -rd

Where:

• -r: Replace the existing instance if there is one
• -d: Run in the background (daemon)

Troubleshooting

Input Method Installed but Cannot Switch / No Candidate Window

1. Confirm whether the Fcitx5 process exists:

radxa@zero$

ps -ef | grep -E "fcitx5($|\\s)" | grep -v grep

2. Run the diagnosis tool (the output will indicate missing components / environment variable issues):

radxa@zero$

fcitx5-diagnose

3. Use im-config to select fcitx5 and log in again

Cannot Input Only in Certain Applications

This is usually related to environment variables or frontend modules:

• Check GTK_IM_MODULE / QT_IM_MODULE / XMODIFIERS
• Test again after logging out and logging back in
• In Wayland environments, Electron applications may need flags to be added at startup. The specific flags may vary by application. Please search for <application-name> + wayland for more information.

tip

In most cases, to add flags for an Electron application you create a <application-name>-flags.conf file under the ~/.config/ directory with the following content:

--enable-features=UseOzonePlatform --ozone-platform=auto --enable-wayland-ime --wayland-text-input-version=3

This is for reference only. The exact configuration may vary by application. Please search for more detailed information according to the specific application.

Wayland vs X11

The way input method support is integrated under Wayland may differ between desktop environments.

If you encounter problems in a Wayland session, you can try:

1. First verify in an X11 session (the login screen usually allows you to select the session type)
2. Make sure you are using the desktop and input method combination recommended by the system