How a Galaxy Z Fold 8 Developer Recreated the iPhone Duo’s Fold Animation

A day after Apple unveiled iPhone Duo, developer moomanjohnny showed a Galaxy Z Fold 8 producing a similar visual transition as it opened. The result looks like a home screen flowing from the cover display onto the inner display—but it is best understood as a technically clever visual demo rather than a feature users can install. 516

The basic idea: tie the animation to the hinge

The developer’s approach was to read the Fold 8’s hinge-angle data in real time and use that changing value to control an animation across both displays. Rather than playing a fixed transition after the phone reaches a particular position, the effect tracks the physical movement of the foldable as it opens and closes. 35

The key pieces were:

• Hinge-angle sensor data to determine how far the device was open.
• Android Graphics Shading Language (AGSL) to render the visual transition.
• Android’s Presentation API to render the effect on the device’s displays. 59

As the hinge angle changes, the shader adjusts the images: blurring, cross-fading, and transforming them to create the impression of continuous content moving across the hinge. 58

Why the animation uses screenshots, not live One UI

The most important limitation is what the demo actually animates. It does not manipulate the live launcher, notifications, or arbitrary apps. Instead, it uses captured screenshots representing the outer and inner displays, then interpolates between those static images. 5811

That distinction matters because a regular Android app does not have the privileges needed to capture, compose, and replace all system UI content at the compositor level. Components such as SystemUI and SurfaceFlinger are restricted to privileged software, preventing a third-party app from applying this treatment seamlessly to the entire operating system. 15

In other words, the proof of concept recreates the appearance of a continuous handoff. It does not provide live, system-wide continuity.

A strong hardware demonstration, not yet a consumer feature

The experiment is still meaningful. It shows that the Fold 8 can supply hinge-position data precise enough to synchronize a display transition with the device’s physical motion. Android has supported hinge-angle reporting for foldables, enabling developers to build animations that respond to the device’s opening angle. 3

But a production-quality One UI feature would require more than this prototype:

• privileged integration with Android’s system rendering pipeline;
• smooth handling of live applications and changing content;
• performance and battery optimization; and
• a design that remains useful beyond the initial visual novelty.

The creator also reportedly noted that the illusion is most persuasive when viewed head-on, since the cover and inner panels remain physically separate displays. The effect may be eye-catching, but that does not automatically make it a better everyday interface. 1

What it means for Samsung

The demo does not prove Samsung can copy the implementation behind Apple’s animation, nor does it mean the effect is ready to be added as a downloadable launcher. It does indicate that a similar, native One UI transition may be technically feasible if Samsung chooses to build it with system-level access and live-content support. 315

Apple announced iPhone Duo on September 9. The company says the foldable will be available for pre-order on October 16, launch on October 23, and start at $1,999 in the U.S. 18