UIRotationEffect

Credit: @alonsoholmes for most of this solution.

Explanation

As of iOS 13.5, SwiftUI’s rotationEffect modifier takes the “long way around” when animating changes in rotation. For example, a rotation from 350° to 20° will cover 330° of rotation, even though those angles have only 30° of separation.

UIKit’s animation libraries handle this situation correctly. This Swift Package is a simple wrapper, accessible by modifier, that adds this UIKit rotation behavior to your SwiftUI view.

Installation

UIRotationEffect supports Swift Package Manager. Simply add this url in XCode > File > Swift Packages > Add Package Dependency:

https://github.com/DominicHolmes/UIRotationEffect

Usage

Import UIRotationEffect into your project. Then use .uiRotationEffect(angle) wherever you would normally use .rotationEffect(angle).

Because the animation is now handled by UIKit, you’ll have to pass in additional options if you want to customize it. uiRotationEffect takes all the same options as this method.

The full method signature is:

func uiRotationEffect(
    _ angle: Angle, 
    duration: TimeInterval? = nil, 
    delay: TimeInterval? = nil, 
    options: UIView.AnimationOptions? = nil, 
    completion: ((Bool) -> Void)? = nil
) -> some View

Example usage:

VStack {

    Text("UIRotation Effect")
        .font(.caption)

    Image(systemName: "arrow.up")
        .font(.largeTitle)
        .foregroundColor(.primary)
        .padding()
        .border(Color.blue)
        .uiRotationEffect(angle)
        .frame(width: 60, height: 60)

    Text("UIRotationEffect with options")
        .font(.caption)

    Image(systemName: "arrow.up")
        .font(.largeTitle)
        .foregroundColor(.primary)
        .padding()
        .border(Color.blue)
        .uiRotationEffect(angle, duration: 2.0, options: [.curveEaseInOut])
        .frame(width: 60, height: 60)

}

Known Issues (Ideas Welcome)

• Using this modifier with a very large (~1200x1200) SwiftUI view produces visual glitches.
• Explicit frames are required, otherwise the view takes up all available space.