CAShapeLayer animate lineCap property

Question

I would like to animate lineCap property of a CAShapeLayer. Here is my code:

  func animate() {
    let animation = CABasicAnimation(keyPath: "lineCap")
    animation.toValue = CAShapeLayerLineCap.round
    animation.duration = 0.3

    //var progressLayer: CAShapeLayer?
    progressLayer?.add(animation, forKey: "AnimationKey")
  }

Nothing happens. Probably the error is in keyPath, but a can't find proper value

Answer 1

Take a look at the documentation:

https://developer.apple.com/documentation/quartzcore/cashapelayer/1521905-linecap

Search for the word "animatable". You won't find it (at least, not with respect to this property). So your expectation that you can animate this property is wrong.

Answer 2

Line cap is not animatable according to the documentation.

https://developer.apple.com/documentation/quartzcore/cashapelayer