MacLngSwitcher

MacLngSwitcher is a lightweight macOS menu bar utility designed for fast and seamless keyboard layout switching using modifier keys:

• Left Control — Tap once to switch to the English (U.S./ABC) layout.
• Right Control — Tap once to cycle between your other selected keyboard layouts (e.g., Russian, Ukrainian).
• Modifier Combination Safety — Normal shortcuts (like Ctrl+C, Ctrl+V, or holding Control down) are preserved and will not trigger a layout switch.

The utility features a premium, native macOS settings window designed to blend perfectly with system windows, featuring real-time system vibrancy (Vibrancy Popover material), support for Dark/Light themes, and system accent colors.

Features

• Double-Control Map: Left Control for a fixed default layout (English), Right Control to cycle through multiple layouts.
• Custom Sensitivity: Slider to adjust the tap timeout sensitivity (between 0.15s and 0.60s).
• Auto-Start: Modern SMAppService API integration to launch automatically at macOS boot.
• Vibrancy Design: High-fidelity, flat native UI with zero CPU overhead in idle state.
• Self-Contained Build: Built completely via command line without heavy Xcode workspace overhead.

Requirements

• macOS 13.0 (Ventura) or newer.
• Accessibility Access is required for the application to monitor global modifier keys.

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How to Build

You do not need Xcode GUI to build this application. A lightweight compilation script using swiftc is provided.

1. Clone the repository:

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

2. Make the build script executable:

   chmod +x build.sh

3. Build the application:

   ./build.sh

   This will:

   • Generate AppIcon.icns from CoreGraphics script.
   • Compile all Swift sources.
   • Output a native macOS bundle named MacLngSwitcher.app in the root folder.

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How to Install and Run

1. Copy the application to your Applications folder:

   rm -rf /Applications/MacLngSwitcher.app
   cp -R MacLngSwitcher.app /Applications/

2. Open the application:

   open /Applications/MacLngSwitcher.app

3. Grant Accessibility Permissions:
   • The application will request Accessibility access on first launch.
   • Go to System Settings > Privacy & Security > Accessibility and enable MacLngSwitcher.
   • Click Restart Application in the settings window to apply permissions.