KDE Screen Dimmer

A lightweight screen dimmer for KDE Plasma (Wayland) built with Qt 6 and LayerShellQt.

Screen Dimmer creates a fullscreen translucent overlay using the Wayland layer-shell protocol, allowing the display to be dimmed without changing monitor brightness. It runs as a small background daemon and can be toggled instantly with a keyboard shortcut.

Features

• Fullscreen dimming overlay
• Works over fullscreen applications and videos
• Click-through overlay (mouse and scroll events pass through)
• Multi-monitor support
• Keyboard shortcut friendly
• Background daemon with negligible CPU usage while idle

Requirements

• KDE Plasma (Wayland)
• Qt 6
• LayerShellQt
• CMake
• C++20 compatible compiler

Demo

Arch Linux / EndeavourOS

sudo pacman -S qt6-base layer-shell-qt cmake

Build

git clone https://github.com/<your-username>/screen-dimmer.git
cd screen-dimmer

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build

Install

install -Dm755 build/screen-dimmer ~/.local/bin/screen-dimmer

Running

Start the daemon:

screen-dimmer &

Toggle the overlay:

pkill -USR1 -x screen-dimmer

Stop the daemon:

pkill -x screen-dimmer

Keyboard Shortcut

A helper script is provided in scripts/toggle-dimmer.sh.

Bind the script to a keyboard shortcut from:

System Settings → Keyboard → Shortcuts → Custom Shortcuts

Autostart

Copy scripts/screen-dimmer.desktop to:

~/.config/autostart/

Update the Exec= path if necessary.

Project Structure

.
├── CMakeLists.txt
├── LICENSE
├── README.md
├── src/
│   └── main.cpp
└── scripts/
    ├── screen-dimmer.desktop
    └── toggle-dimmer.sh

Limitations

• Currently tested only on KDE Plasma Wayland.
• Requires LayerShellQt.
• Other desktop environments and compositors have not been tested.

License

Released under the MIT License.