KWin Plugin: Emoji Picker

I want to easily type emojis on my laptop and noticed that the current plasma-emojier is a standalone application which only copies the emoji to the clipboard. My goal was to type emojis directly into the application I’m using. This is a much faster and more seamless workflow.

To achieve this goal I looked into preexisting solutions in KDE and found KEmoji, a KDE Frameworks library for emojis. I also looked into how other compositors handle this and found that implementing it as a KWin plugin would be a good solution.

From Standalone App to KWin Plugin

By moving the emoji picker into KWin, we can safely bypass Wayland’s strict input isolation. The new picker is implemented as a KWin internal overlay effect, acting as an extension of KWin’s input handling.

Key Features:

1. Cursor Alignment: KWin queries its internal zwp_text_input state to retrieve the exact cursor geometry of the focused surface, allowing the overlay to open exactly where you are typing.
2. kemoji Library: We’ve adopted the new KDE Frameworks library, kemoji, for the backend. This provides unified models and data for emojis, search, and history.
3. Secure Injection: Upon selection, KWin calls InputMethod::commitString() to safely inject the emoji into the active text buffer.
4. Input Interception: Keyboard events are temporarily routed to the overlay’s search field without stealing focus from the target application, preventing flicker or glitches.

The picker can be easily triggered using Meta + . (period) and allows you to search for emojis and insert them into the active text buffer.