A macOS reference image viewer with adjustable window opacity for artists and designers.
- Adjustable Window Opacity: Control the entire window's transparency from 5% to 100%
- Image Loading: Drag and drop, File → Open (⌘O), or open from Finder (right-click → Open With, drop on the Dock icon, or
open -a OpacityWindow image.png) - Always on Top / Lock: Pin the window above other apps, and lock it to click through to whatever is behind (⌘L)
- Zoom & Pan: Pinch to zoom, drag to pan, double-click to reset
- Smart Controls: Controls become fully visible on hover for easy access
- Minimal UI: Clean, unobtrusive interface that stays out of your way
- PNG, JPEG, TIFF, GIF, HEIC, WebP
- Open the app and drag an image onto the window, or press ⌘O to open a file picker
- Adjust opacity using the slider in the control bar (5% - 100%)
- Zoom in/out using pinch gestures or the +/- buttons
- Pan around by clicking and dragging when zoomed in
- Reset view by double-clicking or using the reset button
- Hover over controls to make them fully visible
- macOS 14.0 (Sonoma) or later
- Xcode 15.0 or later
- Open
OpacityWindow.xcodeprojin Xcode - Select your development team in Signing & Capabilities
- Build and run (⌘R)
| Action | Shortcut |
|---|---|
| Open Image | ⌘O |
| Toggle Lock | ⌘L |
| Quit | ⌘Q |
OpacityWindow registers as an alternate handler for images, so it appears in Finder's Open With menu without displacing Preview as the default.
- SwiftUI for the user interface
- AppKit integration for window-level opacity control via
NSWindow.alphaValue - Native macOS app with modern SwiftUI lifecycle
OpacityWindow/
├── OpacityWindowApp.swift # App entry point & window configuration
├── ContentView.swift # Main UI with controls overlay
├── ImageView.swift # Image display with zoom/pan gestures
├── WindowAccessor.swift # NSWindow bridge for opacity control
├── UnlockButtonWindow.swift # Floating unlock affordance while locked
├── Assets.xcassets/ # App icons and colors
├── Info.plist # App configuration
└── OpacityWindow.entitlements # App sandbox permissions
MIT License