Reverse the rotation of UIImageView using CAKeyframeAnimation

Question

I'm using the following code to rotate an image infinitely, the rotation is clockwise but I also need it to reverse rotation to counter clockwise every 1-2 rotations and then back to clockwise, how to get this to work?

    /// Image Rotation - CAKeyframeAnimation
func rotate(imageView: UIImageView, rotationSpeed: Double) {

    let animation = CAKeyframeAnimation(keyPath: "transform.rotation.z")

    animation.duration = rotationSpeed
    animation.fillMode = CAMediaTimingFillMode.forwards
    animation.repeatCount = .infinity
    animation.values = [0, Double.pi/2, Double.pi, Double.pi*3/2, Double.pi*2]

    /// Percentage of each key frame
    let moments = [NSNumber(value: 0.0), NSNumber(value: 0.1),
                   NSNumber(value: 0.3), NSNumber(value: 0.8), NSNumber(value: 1.0)]
    animation.keyTimes = moments

    imageView.layer.add(animation, forKey: "rotate")
}

Have a look on this https://stackoverflow.com/questions/9468707/ios-cakeyframeanimation-rotationmode-on-uiimageview — Abhishek, Sep 05 '19 at 13:54

score 1 · Accepted Answer · answered Sep 05 '19 at 14:00

1

Set animation.autoreverses = true, will reverse an animation.

answered Sep 05 '19 at 14:00

Sagar Chauhan

5,115
2
17
48

score 0 · Answer 2 · answered Sep 05 '19 at 16:53

0

for counter clockwise rotation, you can do this:

self.imageView?.transform = CGAffineTransform(rotationAngle: -2*CGFloat.pi)

answered Sep 05 '19 at 16:53

Frankenxtein

386
2
16

Reverse the rotation of UIImageView using CAKeyframeAnimation

2 Answers2