Using CALayers in SwiftUI

SwiftUI does not support CALayers directly, the equivalent functionality has been essentially combined within Views themselves.

There is also no compelling reason to use CALayers to obtain further acceleration, as that has also been implemented by other means in SwiftUI; in particular, there is no need to use CALayers to render really complex hierarchies of views because SwiftUI does not use Auto Layout. In UIKit, that would have had a rendering cost that increases with the number of views to be rendered. There is not a “layer” abstraction on top of View in SwiftUI.

That said, there are times when you need to implement code that was originally developed for UIKit. SwiftUI provides a protocol, UIViewRepresentable, that can be used for this purpose and allows to basically embed a UIView within a SwiftUI view.

If you need to use a custom UIView within SwiftUI, bear in mind that it is faster to use CALayers rather than Core Graphics.