A lightweight GTK4 application that monitors battery levels and displays customizable alerts when your battery is running low. Perfect for Linux users who want elegant, non-intrusive battery warnings.

• Real-time battery monitoring - Continuously tracks battery percentage and charging status
• Dual-threshold system - Configurable low and risky battery levels
• Customizable actions - Execute any command (hibernate, suspend, etc.) via secondary button
• CSS styling support - Fully customizable appearance with CSS
• Keyboard shortcuts - ESC key to dismiss alerts
• Daemon mode - Run silently in the background
• Auto-hide logic - Smart window visibility based on battery state and user interaction

• GTK4 development libraries
• GLib development libraries
• A C compiler (clang recommended)
• Linux with /sys/class/power_supply/ battery interface

# Install dependencies (Ubuntu/Debian)
sudo apt install libgtk-4-dev libglib2.0-dev build-essential

# Install dependencies (Arch Linux)
sudo pacman -S gtk4 glib2 base-devel

# Compile
make

# Install to /usr/local/bin/lbagtk (optional)
make install

# Run with defaults
./lbagtk

# Run as daemon
./lbagtk --daemon

# Custom thresholds
./lbagtk --low 25 --risky 15

# Custom styles
./lbagtk --styles ~/.config/myapp/custom.css

The application supports CSS theming. With gtk4, :root { ... } and var(--name) are available. Create a CSS file (default: ~/.config/gall/lbagtk.css) with these classes:

/* Main window */
.battery-alert-window {
    background: rgba(40, 40, 40, 0.95);
    border-radius: 12px;
    border: 2px solid #ff6b6b;
}

/* Header text */
.battery-alert-header {
    color: #ff6b6b;
    font-weight: bold;
}

/* Battery info text */
.battery-alert-info {
    color: #ffffff;
}

/* Action button (hibernate/suspend) */
.battery-alert-action-btn {
    background: #ff6b6b;
    color: white;
    border-radius: 6px;
    padding: 8px 16px;
}

/* Dismiss button */
.battery-alert-close-btn {
    background: #444444;
    color: white;
    border-radius: 6px;
    padding: 8px 16px;
}

/* Container styling */
.battery-alert-main-container {
    padding: 20px;
}

.battery-alert-label-container {
    margin-bottom: 15px;
}

.battery-alert-button-container {
    margin-top: 10px;
}

The application automatically scans /sys/class/power_supply/BAT0 through /sys/class/power_supply/BAT9 to find your battery interface, reading from:

• capacity file for battery percentage
• status file for charging state

• Above low threshold + charging: Window hidden
• Below low threshold: Warning appears (secondary button inactive, visible)
• Below risky threshold: Window reappears, action button becomes active
• User dismissal: Window hides temporarily (low ➜ risk) or permanently after second dismiss

The secondary action button uses fork() and execl() to launch commands without blocking the main application

• Ensure /sys/class/power_supply/BAT* directories exist
• Check battery numbering (some systems use BAT1, BAT2, etc.)
• Verify read permissions on battery files

• Confirm GTK4 is properly installed
• Check if display server is running (X11/Wayland)
• Try running without daemon mode first

• Verify file path and permissions
• Use absolute paths instead of ~ expansion
• Try running without daemon mode for CSS error logs

This project is licensed under the MIT License - see the LICENSE file for details.

Free and open source software that you can use, modify, and distribute! 🫠

Built with 💜 for Linux