
ビスター(Vistar)
1.5K posts

ビスター(Vistar)
@Lmssync
UIKit SwiftUI Exploring Internals









CPU and thermal performance in a SwiftUI list explains why we had so many hitches. Even at rest, no scrolling, the CPU screamed at 100% capacity to render every gif, and well past 100% (distributing work across CPU cores) when I scrolled. The “Very High” energy impact rapidly heated my device. The measured thermal trace crept up towards Serious. When I wasn’t paying attention, the app was even killed by the OS, presumably hitting a critical thermal spike. After giving a serious beating to my shiny new A19 chip, the same feed in UIKit produced comparatively nearly trivial CPU and energy usage. * At rest, UIKit dropped as low as 11% CPU utilisation, vs a consistent 100% for the SwiftUI version * Energy usage correspondingly held at High for UIKit, vs Very High for SwiftUI. I gave up waiting for the thermal profile to hit Fair after 3 minutes. Read my scientific performance comparison right here 🧪 blog.jacobstechtavern.com/p/swiftui-vs-u…














@zats @Barbapapapps UIKit’s ScrollEdgeEffectView (a Swift class, hence no UI prefix 🤢) uses a CABackdropLayer with luma tracking enabled. The intensity of the “shadow” and whether or not the blur effect is enabled is based off the reported average luma composited below the backdrop layer.

Finally, we have the best of both worlds! You can now disable the Liquid Glass highlights on iOS 26.4 Beta. Definitely turning them off.








