Alt_Shift

Decky Loader plugin: Fixes Steam On-Screen Keyboard (OSK) input and layout switching in Wayland & Game Mode

English • Русский

A plugin for Decky Loader that resolves Steam virtual on-screen keyboard (OSK) input and layout switching issues in Wayland / X11 (KDE Plasma Desktop Mode) and Game Mode (Gamescope) on SteamOS and other Arch-based distributions.

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📌 Background: What was the issue?

Steam's native on-screen keyboard engine (steamui.so) emulates keystrokes using the legacy X11 protocol XTestFakeKeyEvent. In modern Wayland sessions:

1. Input blocked in native Wayland windows: Wayland compositors (KWin Wayland, Gamescope) isolate client windows from synthetic XTest events, causing the OSK to fail to type or output unwanted numbers ('1') instead of characters.
2. Missing secondary layouts in X11/XKB: Attempting to type non-Latin/Cyrillic characters causes XKeysymToKeycode failures resulting in keycode 2 (KEY_1).
3. Double / Triple typing: Standard text forwarding methods often result in duplicate or triplicate key presses per touch.
4. Layout desynchronization: Toggling language layouts on the virtual keyboard does not propagate to the system compositor.

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✨ Features

• ⌨️ Kernel-level hardware input via Linux /dev/uinput: Direct keystroke injection through virtual kernel input device (evdev). Compatible with all Wayland and XWayland windows, games, browsers, and terminals.
• 🎯 Clean single-strike input: Intercepts SteamClient.Input.ControllerKeyboardSendText in Steam CEF to prevent character duplication.
• 🔄 Dynamic layout synchronization:
  • Desktop Mode (KDE Plasma): Instantaneous layout switching via D-Bus (org.kde.keyboard /Layouts) with dynamic layout index discovery.
  • Game Mode (Gamescope): Automatic layout synchronization upon character input.
• 🇷🇺 Comprehensive Cyrillic support: Correct input for all Cyrillic letters (uppercase and lowercase), punctuation, digits, and special keys (Backspace, Enter, Tab, arrows, Escape).
• ⚡ Zero-Reboot Setup: Automatically initializes system XKB environment and KDE daemon states on startup — no manual console commands or reboots required after installation.
• 🎛 Minimalist footprint: Clean and lightweight UI in Quick Access Menu (QAM). Can be hidden in Decky Loader settings while continuing to run in the background.

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📦 Installation

1. Download the release archive Alt_Shift.zip from GitHub Releases or GitFlic.
2. On your Steam Deck, open the Decky Loader menu (... button).
3. Click the Gear icon (Decky Loader Settings) -> Developer tab.
4. Select "Install plugin from ZIP" and choose the downloaded Alt_Shift.zip.

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🛠 Building from source

Requires Node.js and pnpm (or npm):

# Clone the repository
git clone https://github.com/Kowalski-coder/Alt_Shift.git
cd Alt_Shift

# Install dependencies
pnpm install

# Build frontend bundle
pnpm run build

# Package release ZIP archive
rm -rf /tmp/decky-pack && mkdir -p /tmp/decky-pack/Alt_Shift/dist
cp dist/index.js /tmp/decky-pack/Alt_Shift/dist/
cp main.py plugin.json package.json README.md README_RU.md LICENSE /tmp/decky-pack/Alt_Shift/
(cd /tmp/decky-pack && zip -r ~/Alt_Shift.zip Alt_Shift)

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📁 Project Structure

Alt_Shift/
├── dist/
│   └── index.js           # Compiled frontend (Decky IIFE bundle)
├── src/
│   └── index.tsx          # Steam CEF hook & QAM interface component
├── main.py                # Python backend (uinput driver, D-Bus XKB sync)
├── plugin.json            # Decky Loader plugin manifest
├── package.json           # Package description & build scripts
├── tsconfig.json          # TypeScript configuration
├── rollup.config.js       # Rollup bundler configuration
├── LICENSE                # BSD-3-Clause License
├── README.md              # Documentation (English - Default)
└── README_RU.md           # Documentation (Russian)

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👤 Author & License

• Author: Kowalski
• License: BSD-3-Clause