animations | ios.dev

To animate values, SwiftUI uses the Animatable protocol, which has only one requirement: the animatableData property with a type that conforms to the VectorArithmetic protocol.

When you use the animation(_:) modifier on an equatable view, SwiftUI animates any changes to animatable properties of the view. A view’s color, opacity, rotation, size, and other properties are all animatable.
When the view isn’t equatable, you can use the animation(_:value:) modifier to start animations when the specified value changes.

Animation vs. transition:

animation: animate a view onscreen from one state to another.
transition: animate the insertion of a new view or the removal of an existing view.

When repeating an animation, the ﬁrst repeat animates in the forward direction, the second repeat in the reverse direction, and so on. We can turn this behavior oﬀ by passing false to the the autoreverses parameter of repeatCount.