文章目录：

平面旋转
   顺时针旋转90度
   顺时针旋转180度
   逆时针旋转90度
   持续旋转
3D旋转
   向量为(1, 0, 0)时
   向量为(0, 1, 0)时
   向量为(0, 1, 0)时
   持续旋转

平面旋转：

顺时针旋转90度：

            UIView.animate(withDuration: 1) {
                self.captainLabel.transform = CGAffineTransform(rotationAngle: CGFloat.pi / 2)
            }

顺时针旋转180度：

            UIView.animate(withDuration: 1) {
                self.captainLabel.transform = CGAffineTransform(rotationAngle: CGFloat.pi)
            }

逆时针旋转90度：

需要用到

    /* Invert `t' and return the result. If `t' has zero determinant, then `t'
       is returned unchanged. */
    /* 对 调用该方法的 CGAffineTransform实例 进行取反 并返回 */
    @available(iOS 2.0, *)
    public func inverted() -> CGAffineTransform

事例代码

        UIView.animate(withDuration: 1) {
            self.captainLabel.transform = CGAffineTransform(rotationAngle: CGFloat.pi / 2).inverted()
        }

持续旋转：

需要用到

    /* 用来让 CGAffineTransform实例 关联我们指定的 CGAffineTransform 实例 */
    /* Concatenate `t2' to `t1' and return the result:
         t' = t1 * t2 */
    
    @available(iOS 2.0, *)
    public func concatenating(_ t2: CGAffineTransform) -> CGAffineTransform

事例代码

        Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { (_) in
            UIView.animate(withDuration: 1) {
                self.captainLabel.transform = CGAffineTransform(rotationAngle: CGFloat.pi / 2).inverted().concatenating(self.captainLabel.transform)
            }
        }

3D旋转：

需要用到

/* 对CATransform3D的实例进行变换（向向量(x, y, z)的方向 同时 以向量为轴 旋转 angle 角度）并返回新的CATransform3D实例。*/
/* Rotate 't' by 'angle' radians about the vector '(x, y, z)' and return
 * the result. If the vector has zero length the behavior is undefined:
 * t' = rotation(angle, x, y, z) * t. */

@available(iOS 2.0, *)
public func CATransform3DRotate(_ t: CATransform3D, _ angle: CGFloat, _ x: CGFloat, _ y: CGFloat, _ z: CGFloat) -> CATransform3D

向量为(1, 0, 0)时：

            UIView.animate(withDuration: 1) {
                self.captainLabel.layer.transform = CATransform3DMakeRotation(CGFloat.pi, 1, 0, 0)
            }

向量为(0, 1, 0)时：

            UIView.animate(withDuration: 1) {
                self.captainLabel.layer.transform = CATransform3DMakeRotation(CGFloat.pi, 0, 1, 0)
            }

向量为(0, 0, 1)时：

            UIView.animate(withDuration: 1) {
                self.captainLabel.layer.transform = CATransform3DMakeRotation(CGFloat.pi, 0, 0, 1)
            }

持续旋转：

        Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { (_) in
            UIView.animate(withDuration: 1) {
                self.captainLabel.layer.transform = CATransform3DRotate(self.captainLabel.layer.transform, CGFloat.pi / 2, 1, 0, 0)
            }
        }