Display-Lock

Display-Lock is a lightweight Windows application that locks your mouse cursor to a selected window. Designed with performance in mind, it's the perfect tool for gamers using multi-monitor setups or anyone who needs to prevent accidental cursor movement outside a specific window.

Quick Links: Features | Installation | Building | Configuration | Contributing

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Features

• Cursor Locking - Lock your cursor to a selected window with a single click
• Window Selection - Easy UI to choose from open windows on your system
• Borderless Window Mode - Convert any window to borderless for a cleaner look
• Fullscreen Expansion - Expand windows to fill your entire monitor
• Application Whitelist - Auto-lock cursor for specified applications
• System Tray Integration - Minimize to system tray with quick context menu access
• Update Checker - Automatic checking for new versions
• Lightweight & Portable - Pure Win32 API implementation with no external dependencies
• Multi-Monitor Support - Seamlessly works across multiple monitor setups

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Installation

Download

Download the latest release from the Releases page.

System Requirements

• Windows 10 or later
• No installation required - simply extract and run the executable

Display-Lock is fully portable and can be run from any location. No administrative privileges are required.

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Getting Started

1. Download and run the executable
2. Select a window from the "Window Select" tab
3. Click "Lock Cursor" to confine your cursor to that window
4. Click "Unlock" or switch focus to another window to release the lock

Using the Tabs

• Window Select: Choose which window to lock the cursor to
• Settings: Configure application behavior
• Applications: Add applications to the whitelist for automatic cursor locking

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Configuration

Configuration files are stored in %APPDATA%/DisplayLock/. Settings are saved in a binary .DLOCK format.

Available Settings

Setting	Description
Minimize on Start	Automatically minimize the application on startup
Bring to Foreground	Automatically bring the locked window to the foreground
Borderless Window	Convert the selected window to borderless mode
Fullscreen	Expand the window to fill the entire monitor
Check for Updates	Periodically check for new versions
Minimize to Tray	Hide the application in the system tray instead of taskbar

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Use Cases

• Gaming: Keep your cursor confined to a windowed game, preventing accidental clicks outside the window
• Multi-Monitor Gaming: Play fullscreen games on one monitor without cursor drift to others
• Window Management: Convert borderless fullscreen windows for streaming or video capture
• Application Monitoring: Automatically lock cursor when specific applications are in focus

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Building from Source

Requirements

• CMake 3.24 or later
• Visual Studio 2022 with MSVC
• Windows 10 SDK

Build Instructions

# Configure and build (Release)
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --config Release

# Configure and build (Debug)
cmake -B build -DCMAKE_BUILD_TYPE=Debug
cmake --build build --config Debug

# Run tests
ctest --test-dir build -C Release

# Run a specific test
ctest --test-dir build -C Release -R SettingsTest

The compiled executable will be in the build directory.

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Project Structure

• src/ - Main application with Win32 UI
• src/components/ - Core functionality library
  • win.c - Cursor locking logic
  • settings.c - Configuration persistence
  • applications.c - Application whitelist management
  • notify.c - System tray integration
  • update.c - Version checking
  • menu.c - Menu UI handling
• tests/ - Google Test test suite
• docs/ - Documentation and assets

For more details, see the CLAUDE.md architecture documentation.

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Screenshots & Demo

Main Application Window

Borderless Window Mode

Cursor Locking in Action

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Contributing

Contributions are always welcome! Please read our Contributing Guidelines before submitting a pull request.

Pull Request Process

1. Discuss proposed changes via GitHub issues before starting work
2. Work on the develop branch (or a branch checked out from develop)
3. For hotfixes, work off the master branch
4. Update CHANGELOG.md with your changes
5. Add tests if applicable
6. Ensure all builds pass and tests succeed before submitting

Things to Avoid

• External dependencies (this project prioritizes being lightweight)
• Manual version number changes or build script modifications
• Machine-specific project configurations

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License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

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Support & Links

• Report Issues: GitHub Issues
• View Changelog: CHANGELOG.md
• Latest Releases: GitHub Releases
• Download Latest: Download