The iPhone Duo folding animation, recreated for the MacBook Pro lid.
Signed with Developer ID and notarized by Apple: open the DMG, drag Lid Up to Applications, launch, grant Screen Recording. No security dialog. All releases →
Close the lid and the desktop stays anchored in space while the glass sweeps through it: the picture tilts, frosts over and slips into black before the hinge shuts. Open it back up before the Mac sleeps and it returns the same way.
The hinge has a sensor. Every recent MacBook has a small angle sensor in the hinge between the keyboard and the lid. macOS uses it to know when the lid is about to close so it can put the Mac to sleep at the right moment. The sensor reports the opening angle in degrees: 0° is fully closed, roughly 90° is the lid straight up, and most people work somewhere around 110° to 130°. On recent models it reports in hundredths of a degree, about ten times a second.
Lid Up reads that angle. macOS exposes the sensor as a plain input device (the same interface a keyboard or trackpad uses), so the app can read it without any special permission. While the lid sits still, the app checks it ten times a second and does nothing else.
The lid starts to move. As soon as the angle begins to drop, the app starts a live stream of your built-in display through ScreenCaptureKit. This is why Screen Recording is the one permission it asks for. The stream only runs while the lid is moving and stops a few seconds after it settles.
The picture stays where the screen was. Once the lid has closed a couple of degrees past where it was resting, the app puts a full-screen, click-through window over the display. Instead of showing the desktop flat on the glass, it draws it as if the desktop were a sheet floating in the air exactly where the screen used to be, viewed from where you are sitting. As the physical screen tilts through that sheet, the picture appears to stay in place: the top slides off the glass into black, the sides fan out with perspective, and the whole image frosts over and darkens. By about 25° it is fully black, just before macOS puts the Mac to sleep.
Open it again and it comes back. If you lift the lid before the Mac sleeps, the same maths runs in reverse and the desktop slides back into place. Once the lid passes the anchor angle, or holds still for a couple of seconds, the overlay fades out and hands the screen back.
Under the hood. Everything is drawn on the GPU with Metal: each screen pixel is traced back through the tilted glass to the anchored picture, and a blur pyramid and darkening curve are applied by height. A small spring smooths the ten-per-second sensor readings into motion at the display's refresh rate.
- A MacBook with the continuous lid angle sensor (M2 MacBook Air or later, 14/16-inch MacBook Pro with M1 Pro or later). Tested on a 16-inch M5 Max.
- macOS 15 or later. Xcode 27 to build.
Exactly one: Screen Recording. ScreenCaptureKit needs it to hand the app a live copy of the built-in display while the lid moves. Frames stay in GPU memory for the length of the fold and are never written or sent anywhere.
The lid angle itself is read from the hinge sensor over IOKit HID, which macOS exposes without any prompt. Launch at login is opt-in and uses the standard Login Items entry.
macOS ties the Screen Recording grant to the app's code signature. The project signs with an Apple Development identity so the grant survives rebuilds; with ad-hoc signing every build would need it granted again.
- Download
LidUpAnimation-<version>.dmgfrom the latest release, open it, and drag Lid Up into Applications. - Open it. Release DMGs are signed with Developer ID and notarized by Apple, so there is no security dialog.
- Grant Screen Recording when the app asks, then relaunch it.
Building the DMG: ./build-dmg.sh archives a Release build, exports it with
the team's Developer ID certificate, wraps it in a DMG, submits it to Apple's
notary service using the LidUp keychain profile
(xcrun notarytool store-credentials LidUp …), staples the ticket and writes
dist/LidUpAnimation-<version>.dmg plus a SHA-256 file. SIGN_IDENTITY=-
builds an ad-hoc DMG instead; the GitHub Actions workflow produces one of
those as a build artifact for every v* tag, and users of it need
Privacy & Security → Open Anyway.
Open LidUpAnimation.xcodeproj in Xcode and run, or:
xcodebuild -project LidUpAnimation.xcodeproj -scheme LidUpAnimation \
-configuration Release -derivedDataPath build -destination 'platform=macOS' build
open build/Build/Products/Release/LidUpAnimation.appThe app lives in the menu bar. The first launch explains the permission and asks for it. Preview the fold plays a scripted lid sweep without moving the lid; before Screen Recording is granted it plays over the desktop wallpaper instead of the live screen.
| Setting | What it does | Default |
|---|---|---|
| Anchor angle | The picture anchors where the lid rests, but never above this. Closing past it starts the fold; opening past it clears it. | 100° |
| Starts after | Degrees the lid must move from rest before the fold begins, when resting below the anchor. | 2° |
| Fully dark at | Lid angle where the picture is completely black. | 25° |
| Viewing distance | Eye distance in screen heights. Smaller exaggerates the perspective. | 2.5 |
| Blur | Gaussian radius at full fold, in points. | 90 |
| Darkening | How dark the picture gets. | 1.0 |
| Clear when still | Hand the screen back after the lid holds still. | on, 2 s |
- The opening animation only plays when the Mac did not sleep. After a full close macOS shows the lock screen, and nothing can draw over it without disabling System Integrity Protection.
- Only the built-in display is animated. In clamshell mode the app idles.
- Clicks pass straight through the overlay.
LidUpAnimation --render-check <dir>writes PNGs of the fold over generated artwork at a series of lid angles, without any permission.LidUpAnimation --previewplays the sweep 1.5 s after launch; posting the distributed notificationcom.hemalmodi.LidUpAnimation.previewplays it on a running app. Add--capturableto let screenshots include the overlay.- Diagnostics:
log stream --predicate 'subsystem == "com.hemalmodi.LidUpAnimation"'
See NOTICE.md for attribution.