Adaptive layouts around the fold

When iPhone Duo is partially folded the inner display curves through the middle. Anything sitting in that curve gets harder to read and much harder to tap. The same thing happens to a photo printed across the spine of a book: near the gutter it stops reading as one continuous image.

So the fold is not decoration. It is a real constraint on where content can go — and iOS models it as a reserved region you can query and design around.

Reserved regions

Reserved regions are areas of the view that hardware imposes on your layout. Treat them exactly like the window controls you already work around on iPadOS: not obstacles, just facts about the available space.

Two kinds, and the distinction matters: