Contrast Checker

A minimalist, native utility for measuring color contrast anywhere across your operating system—including native windows, virtual machines, web browsers, and desktop wallpaper.

Built for accessibility testing, design system audits, and fast WCAG 2.2 compliance verification across 🍎 macOS, 🪟 Windows, 🐧 Linux, and 💻 ChromeOS / Web (PWA).

---

Downloads

Download the latest pre-compiled binaries from the GitHub Releases page, or launch the installable Web / Chromebook PWA:

Operating System	Package Format	Download / Launch	Description
🍎 macOS	.dmg	ContrastChecker.dmg	Apple disk image with drag-and-drop /Applications install (Universal 2: Apple Silicon & Intel)
🪟 Windows	.exe	ContrastChecker.exe	Standalone single-file portable executable (x64, zero runtime dependencies)
🪟 Windows	.msi	ContrastChecker.msi	Windows Installer package with Start Menu and Desktop shortcuts
🐧 Linux (x86_64)	.flatpak	ContrastChecker-x86_64.flatpak	Standalone Flatpak bundle for 64-bit Intel & AMD Linux PCs
🐧 Linux (ARM64)	.flatpak	ContrastChecker-aarch64.flatpak	Standalone Flatpak bundle for 64-bit ARM systems (including Apple Silicon virtual machines)
💻 ChromeOS / Web	PWA	svinkle.github.io/contrast-checker	Installable offline-ready Progressive Web App with system-wide EyeDropper screen sampling

Note

🪟 Windows Installation Note (SmartScreen / Unknown Publisher): Because Contrast Checker is a free, open-source project and is not signed with an expensive commercial code-signing certificate, Windows Defender SmartScreen or User Account Control (UAC) may display a "Windows protected your PC" or "Unknown Publisher" prompt when opening the .msi or .exe.

To install:

1. In SmartScreen: click More info → click Run anyway.
2. In UAC: click Yes to confirm installation.
3. Alternatively, right-click the downloaded .msi or .exe, choose Properties, check Unblock at the bottom, and click Apply / OK.

---

Screenshots

---

Platforms

• 🍎 macOS (/macos): Native Swift, SwiftUI, and AppKit application packaged as a Universal 2 binary (Apple Silicon & Intel). Features system-wide eyedropper (NSColorSampler), permanent menu bar companion, dynamic Dock icon hiding, and global system shortcuts (⌃⌥C, ⌃⌥B, ⌃⌥F).
• 🪟 Windows (/windows): Native C#, .NET 8, and WPF application. Features fullscreen magnification loupe eyedropper, permanent system tray companion, standalone single-file .exe, WiX .msi installer, and global shortcuts (Ctrl+Alt+C, Ctrl+Alt+B, Ctrl+Alt+F). Runs natively on x64 and seamlessly on ARM64 Windows via Prism emulation.
• 🐧 Linux (/linux): Native GTK 4 application packaged as universal Flatpak bundles for both x86_64 and aarch64. Features clean floating card experience with crisp squared corners, multi-desktop screen color sampling (via FreeDesktop XDG Desktop Portal on Wayland and native X11 with libX11 and _NET_WM_ICON taskbar support), and accessible keyboard navigation.
• 💻 ChromeOS / Web PWA (/web): Zero-dependency Progressive Web App hosted on GitHub Pages for Chromebooks and desktop browsers. Features full-screen OS pixel sampling via the Chromium EyeDropper API (with <input type="color"> fallback), offline Service Worker caching, standalone window mode, and full keyboard accessibility (Alt+B, Alt+F).

---

Quick Start & Building from Source

Each operating system provides dedicated build scripts to package release assets:

🍎 macOS

For full documentation, shortcuts, and permissions, see the macOS README.

# Build the application bundle (build/ContrastChecker.app)
make macos

# Build installable DMG (build/ContrastChecker.dmg)
make dmg
# or run directly: ./macos/create_dmg.sh

# Run automated tests
make test-macos

🪟 Windows

For full documentation, shortcuts, and installer details, see the Windows README.

:: Build both ContrastChecker.exe and ContrastChecker.msi
windows\build.bat

Or using PowerShell / Make:

# Build self-contained single-file ContrastChecker.exe
powershell -ExecutionPolicy Bypass -File windows/build.ps1

# Build installable ContrastChecker.msi (via WiX)
powershell -ExecutionPolicy Bypass -File windows/build.ps1 -BuildMsi

🐧 Linux

For full documentation, dependencies, and desktop integration, see the Linux README.

# Run unit tests
make test-linux

# Build standalone ContrastChecker.flatpak bundle
make flatpak
# or run directly: ./linux/build_flatpak.sh

# Install the Flatpak bundle (x86_64 or aarch64)
flatpak install --user ContrastChecker-x86_64.flatpak

💻 ChromeOS / Web (PWA)

For full documentation, Chromebook installation steps, and GitHub Pages configuration, see the Web PWA README.

# Run automated unit & PWA manifest tests
make test-web

# Serve locally at http://localhost:8000
make web

---

License

This project is licensed under the MIT License.