tracksVelocity
Whether this transaction will track the velocity of any animatable properties that change.
Declaration
var tracksVelocity: Bool { get set }Discussion
This property can be enabled in an interactive context to track velocity during a user interaction so that when the interaction ends, an animation can use the accumulated velocities to create animations that preserve them. This tracking is mutually exclusive with an animation being used during a view change, since if there is an animation, it is responsible for managing its own velocity.
Gesture onChanged and updating callbacks automatically set this property to true.
This example shows an interaction which applies changes, tracking velocity until the final change, which applies an animation (which will start with the velocity that was tracked during the previous changes). These changes could come from a server or from an interactive control like a slider.
func receiveChange(change: ChangeInfo) {
var transaction = Transaction()
if change.isFinal {
transaction.animation = .spring
} else {
transaction.tracksVelocity = true
}
withTransaction(transaction) {
state.applyChange(change)
}
}