skvirt

A touch-driven on-screen keyboard for KDE Plasma / KWin (Wayland) that works with fcitx5 instead of replacing it.

Unlike input-method-based on-screen keyboards, skvirt does not take over the Wayland input-method slot and does not put fcitx5 into its virtual-keyboard mode. It types by creating a kernel virtual keyboard via /dev/uinput, so key taps travel the normal input path — libinput → KWin → fcitx5 — exactly like a physical keyboard. Your active fcitx5 layout and engine (e.g. keyboard-ru, Pinyin) compose the input and show candidates in fcitx5's usual window, and the fcitx5 tray icon keeps working. fcitx5 never even knows skvirt exists.

Features

• macOS-style panel and key set: the layout of a Mac keyboard — number row, the three letter rows framed by tab / caps lock / shift / return / delete, and a bottom row of 🌐 ⌃ ⌥ ⌘ space ⌘ ⌥ plus the inverted-T arrow cluster — drawn as a floating slab with square caps, in a light or dark appearance that can follow the system colour scheme. ⌃ ⌥ ⌘ latch like the one-shot Shift: tap one, and the next key is sent with it held. 🌐 switches the input source (the fcitx5 IM), and caps lock has its indicator light.
• Touch-driven, Windows-like: touching a text field with a finger/pen pops the keyboard up; reaching for the mouse/touchpad/trackpoint, losing the field, or pressing the ▼ button hides it. A mouse click never summons it.
• Coexists with fcitx5: input goes through fcitx5, so layouts, composing and CJK candidate selection all work normally.
• Autosuggestion bar: word completions above the key rows — Hunspell dictionaries for Latin/Cyrillic layouts, and libime pinyin candidates (the same engine and data as fcitx5-pinyin) when a Chinese IM is active. Tapping a pinyin candidate commits the hanzi directly.
• Voice input via whisper.cpp (optional): tap space, then press-and-hold it to dictate — recording runs while you hold, releasing transcribes and types the text. Talks over HTTP to a whisper-server (default http://127.0.0.1:8080); with no server running the 🎤 corner hint on the space bar stays hidden and the gesture only shows a short note.
• Layout generator: the on-screen rows are generated at runtime from the active IM's xkb symbols (/usr/share/X11/xkb/symbols/*), so any keyboard-XX layout (de, fr, …) shows the right legends on all four typing rows, dead keys (^ ´ ¨) included. Hardcoded QWERTY/ЙЦУКЕН remain as fallback.
• Long-press symbols: holding a key opens an alternates strip — the digit/symbol of its physical position first (1 on q, @ on a, ? on m), then the accented variants of the letter on the cap (à á â ä, ё/й, …). Slide to pick, release to type. What a key hides is printed small in its corner, so the strip is not a secret.
• Optional function row — esc and F1–F12 across the top. With it off, the same keys stay reachable by holding the key below them (and are shown in that key's corner): hold ` for esc, 1 for F1, … = for F12.
• Tablet-mode aware: can auto-show only when the convertible is folded into tablet mode (via the SW_TABLET_MODE evdev switch).
• KDE settings module: System Settings → skvirt (KCM) toggles all of the above live, no restart needed.
• Wayland layer-shell panel docked at the bottom; never steals input focus from the application you are typing into.

Requirements

• KDE Plasma 6 / KWin on Wayland

• Qt 6 (Core, Gui, Quick, Qml, DBus, Network, Multimedia)

• LayerShellQt

• KF6: Config, CoreAddons, I18n, KCMUtils (+ Kirigami at runtime, for the settings module)

• libime (pinyin suggestions) and hunspell (Latin/Cyrillic suggestions; dictionaries hunspell-en_us, hunspell-ru, … install separately — without them only pinyin suggestions work)

• fcitx5 as the active input method

• optional, for voice input: whisper.cpp (Arch: whisper-cpp) running as whisper-server, ideally with its Silero VAD so silence doesn't come back as hallucinated text ("Thanks for watching!"): whisper-server -m ggml-large-v3-turbo.bin -l auto --vad -vm ggml-silero-v5.1.2.bin -vp 200 (-vp 200 pads speech by 200 ms instead of 30, so word edges aren't clipped); a microphone, obviously

• optional: fcitx5-commit (AUR fcitx5-commit-git) — lets skvirt insert dictated text, pinyin candidates and characters the layout has no key for as one input-method commit instead of key taps: instant and layout-independent. Without it skvirt types them (slower; unicode entry for the rest)

• The user must be in the input group (to read the touchscreen via evdev and to write to /dev/uinput):

  sudo usermod -aG input "$USER"

  Log out and back in for the group change to take effect. (For a quick test in the current session without re-login: sg input -c '.../build/skvirt'.)

Build

cmake -B build
cmake --build build

Run

./build/skvirt

Then touch a text field — the keyboard appears. To start it automatically at login, copy skvirt.desktop (adjust the Exec path) to ~/.config/autostart/, or add the binary in System Settings → Autostart.

Settings

Install (sudo cmake --install build) to get the skvirt page in System Settings (or run it from the build tree: QT_PLUGIN_PATH=build/bin kcmshell6 kcm_skvirt). It edits ~/.config/skvirtrc; a running skvirt picks changes up live:

• Show only in tablet mode — auto-show only while the convertible's SW_TABLET_MODE switch is engaged.
• Hide when mouse is moved — reaching for a pointer device dismisses the panel (default on).
• Show autosuggestions — completion/candidate bar above the keys.
• Show symbols on long press — accent popup on held letters, and F1–F12 on the held number row when the function row is off.
• Function key row — esc and F1–F12 on top; the panel keeps its height budget, so the keys shrink to make room.
• Voice input — tap space, then press-and-hold it to dictate. Needs a whisper-server reachable at the configured address (its default port 8080). Speech language auto detects the language per take, a code like ru pins it; left empty, the server's own -l applies — en unless started otherwise. The 🎤 hint on the space bar only appears while the server answers.
• Appearance — light, dark, or follow the system colour scheme.

(The screenshot predates the appearance and function-row options.)

How it works

• UinputKeyboard — creates the /dev/uinput virtual keyboard and injects US-position evdev keycodes (with Shift as needed). Output follows the active fcitx5 layout/IM, per window. Arbitrary Unicode (hanzi candidates, accented letters) goes through fcitx5's unicode addon direct mode (Ctrl+Shift+U, hex, Enter).
• InputMonitor — reads /dev/input/event* and classifies devices by kernel properties (INPUT_PROP_DIRECT = touchscreen vs pointer devices) to tell finger/pen from mouse; also tracks the SW_TABLET_MODE switch.
• KWinVk — asks KWin (org.kde.kwin.VirtualKeyboard) whether the focused window accepts text input, to know when there is a field to type into.
• KeyboardWindow — the layer-shell panel; marked Qt::WindowDoesNotAcceptFocus so mapping it never pulls focus off the app.
• SuggestionEngine — word completions: Hunspell dictionaries for keyboard layouts, libime (PinyinIME + sc.dict + zh_CN.lm) for pinyin IMs.
• LayoutGenerator — parses the active layout's xkb symbols into the four QML typing rows (number row + AD/AC/AB), keeping their US-position names so keys commit by physical position.
• MacTheme.qml — the light/dark palette (and the SF Pro → Inter → Noto Sans font fallback) every key paints from.
• SettingsBridge + kcm/ — KConfigXT settings (skvirtrc) shared with a KQuickManagedConfigModule KCM; KConfigWatcher reloads them live.
• VoiceInput — push-to-talk dictation: records the microphone with Qt Multimedia (16 kHz mono PCM wrapped in WAV) and POSTs the clip to whisper-server's /inference; the transcript is committed through fcitx5-commit when it's installed, else typed on the keys of the active layout (looked up from the generated rows), with the unicode path for characters the layout has no key for.

Limitations

• Input devices are enumerated at startup; hot-plugged keyboards/mice/touchscreens are not picked up until restart.
• Generated layouts cover the four typing rows (group 1 of the basic xkb section); exotic variants and multi-group layouts fall back to the hardcoded QWERTY/ЙЦУКЕН rows. A key whose group-1 symbol has no printable form (an uncommon dead key, say) is dropped from its row, which then renders a little narrower than the rest.
• Pinyin candidates committed from the suggestion bar do not teach fcitx5's history (the candidate is injected as Unicode after cancelling the preedit).
• If focus moves to another text-capable window while in touch mode, the keyboard may stay up until you use the mouse.

License

GPLv3 — see LICENSE.