Erlauncher

A fast, lightweight application launcher written in Zig for X11 desktop environments.

Demo Video • Installation • Usage • Key Bindings

Demo

erlauncher_demo.mp4

Features

• 🚀 Lightweight - Written in Zig, minimal dependencies, fast startup
• 🎨 Modern UI - Frameless window with smooth rounded corners
• ⌨️ Keyboard-First - Arrow keys to navigate, Enter to launch, Escape to close
• 🔍 Real-time Filtering - Instantly filter applications as you type
• 🖥️ Multi-Monitor Aware - Detects cursor position and centers on active monitor
• 📦 Auto-Discovery - Loads .desktop files from standard system locations
• 🎯 Focus Handling - Click outside or lose focus to close

Tested Platforms

Platform	Status
Ubuntu 24.04	✅ Tested
X11	✅ Supported
GNOME	✅ Tested

Installation

Prerequisites

Install required development libraries for X11:

Debian/Ubuntu

sudo apt-get install libx11-dev libxext-dev libxrandr-dev libxft-dev libfontconfig1-dev libfreetype6-dev

Fedora/RHEL

sudo dnf install libX11-devel libXext-devel libXrandr-devel libXft-devel fontconfig-devel freetype-devel

Arch Linux

sudo pacman -S libx11 libxext libxrandr libxft fontconfig freetype2

Building

# Clone the repository
git clone https://github.com/ErlantzCalvo/erlauncher.git
cd erlauncher

# Build the project
zig build

# The executable will be at: zig-out/bin/erlauncher

Usage

Running

# Run directly
./zig-out/bin/erlauncher

# Or use zig build run
zig build run

Setting Up a Keyboard Shortcut (GNOME)

Launch Erlauncher with Super/Windows key:

gsettings set org.gnome.settings-daemon.plugins.media-keys custom-keybindings "['/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/']"
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/ name "Erlauncher"
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/ command "/home/your-path-to/erlauncher/zig-out/bin/erlauncher"
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/ binding "Super_L"

To remove:

gsettings set org.gnome.settings-daemon.plugins.media-keys custom-keybindings "[]"

GUI Method: Settings → Keyboard → View and Customize Shortcuts → Custom Shortcuts → + → Add with name "Erlauncher", full command path, and press Super key.

Key Bindings

Key	Action
Type	Filter applications by name
Arrow Up	Navigate up in filtered list
Arrow Down	Navigate down in filtered list
Enter	Launch selected application
Escape	Close launcher
Click outside	Click outside window closes it

Configuration

Window settings are defined in src/config.zig:

// Window dimensions
window.width: 600
window.height: 400
window.corner_radius: 12

// UI settings
ui.input_height: 50
ui.item_height: 28
ui.max_visible_items: 10

// Font
font.name: "DejaVu Sans-14"

// Colors
colors.selection: #7588F0

Architecture

src/
├── main.zig              # Entry point
├── config.zig            # Configuration constants
├── app/
│   ├── desktop.zig       # .desktop file parsing
│   └── launcher.zig     # Application loading & launching
├── ui/
│   └── ui.zig           # UI state & filtering logic
├── backend/
│   ├── backend.zig       # Backend interface
│   └── x11.zig          # X11 implementation
└── x11/
    └── c_bindings.zig    # X11 C bindings

Technical Details

Window Features

• Centered Window: Calculates screen center using XRandR to detect individual monitors
• Frameless: Uses override_redirect and _MOTIF_WM_HINTS for window decoration bypass
• Rounded Corners: Smooth corners implemented via XShape extension
• Multi-Monitor: Positions window at cursor's monitor center for optimal UX

Display System Support

Works with X11-based display servers:

• ✅ X.Org
• ✅ XWayland (X11 compatibility layer in Wayland)
• ✅ Traditional X11 window managers

Check your display system:

echo $XDG_SESSION_TYPE  # Displays "wayland" or "x11"

Application Loading

Scans standard desktop entry directories:

• ~/.local/share/applications
• /usr/share/applications
• /usr/local/share/applications
• /var/lib/flatpak/exports/share/applications
• /var/lib/snapd/desktop/applications

License

MIT License - see LICENSE for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.