How will the sizes of a View change during an animation when its frame is doubled over half the duration?

If during an animation the frame View doubles in size over half of the animation duration, then the size of the View will change as follows:

• During the first half of the animation, the size of the View will smoothly increase from the original size to double.
• During the second half of the animation, the size will remain at the new increased level (if the animation does not specify a reverse change).

That is, if the total duration of the animation is T, then in time T/2 the frame will double in size, and then in the remaining time T/2, the size will stay constant.

If the animation is set to continuous change, then the size change will be linear or follow a specified curve (ease-in, ease-out) during the first half of the time, and then stabilize.

Example in Swift with UIView.animate:

UIView.animate(withDuration: totalDuration) {
    UIView.animateKeyframes(withDuration: totalDuration, delay: 0, options: [], animations: {
        UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.5) {
            view.frame.size = CGSize(width: view.frame.width * 2, height: view.frame.height * 2)
        }
        UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.5) {
            // Sizes remain constant
        }
    })
}

Thus, the size increase occurs only in the first half of the animation.