ios UIImageView rotation direction in swift at variable degree in clockwise direction

Question

I am rotating image through this code

UIView.animate(withDuration: 2) {

        self.blueNeedleImageView.transform = CGAffineTransform(rotationAngle: CGFloat(myDegreeValue * Double.pi / 180))

    }

Problem is that it is rotating in shortest path. I want always clockwise rotation and rotation degree is variable. this and this does not provide a solution.

iPeter I am converting angle to radians by multiplying with (Double.pi / 180) — Salman Khalid, Mar 18 '19 at 09:18
shortest path mean if want to rotate through 20 degree then it will rotate in clockwise direction but if i want to rotate 340 degree then it will rotate in anti-clockwise direction. — Salman Khalid, Mar 18 '19 at 09:21

score 2 · Accepted Answer · answered Mar 18 '19 at 09:28

2

Just split it to two animations if the angle is more than 180°.

answered Mar 18 '19 at 09:28

andrew.turkin

78
6

nice workaround. but isn't there a proper way because this solution is complicating things. – Salman Khalid Mar 18 '19 at 09:30
It seems like the easiest solution. Note that you can return your view back with `.transform = CGAffineTransformIdentity` – andrew.turkin Mar 18 '19 at 10:53

score 1 · Answer 2 · answered Mar 18 '19 at 10:12

You can rotate your Image as per your requirement with the help of CoreAnimation like below:

let angle = myDegreeValue
if let n = NumberFormatter().number(from: angle) {
    let floatAngle = Double(truncating: n)
    CATransaction.begin()
    let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
    rotationAnimation.byValue = NSNumber(value: floatAngle * (Double.pi / 180))
    rotationAnimation.duration = 2
    rotationAnimation.isRemovedOnCompletion = true

    CATransaction.setCompletionBlock {
          self.blueNeedleImageView.transform = CGAffineTransform(rotationAngle: CGFloat(floatAngle * (Double.pi / 180)))
    }
    self.blueNeedleImageView.layer.add(rotationAnimation, forKey: "rotationAnimation")
    CATransaction.commit()
}

ios UIImageView rotation direction in swift at variable degree in clockwise direction

2 Answers2