将CALayer旋转90度？

func rotateLayer(_ layer: CALayer, angle: CGFloat) {
    // 创建一个旋转动画
    let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
    rotationAnimation.toValue = angle
    rotationAnimation.duration = 0.25
    rotationAnimation.isCumulative = true
    rotationAnimation.repeatCount = 0
    layer.add(rotationAnimation, forKey: "rotationAnimation")
}

// 使用方法
let layer = CALayer()
rotateLayer(layer, angle: CGFloat.pi / 2) // 旋转90度