假设您有一个CALayer
子类作为视图层次结构的一部分,该子类是通过比例和旋转变换创建的,其中角度和比例仅在运行时定义,即:
let layer = CALayer()
layer.frame = CGRect(x: 10, y: 10, width: 100, height: 100)
//where xx and yy are some precomputed values
layer.transform = CATransform3DConcat(CATransform3DMakeScale(xx, xx, 1),
CATransform3DMakeRotation(yy, 0, 0, 1))
let view = UIView() //your view hierarchy
view.addSublayer(layer)
稍后在程序中,我想将此层旋转到特定角度。如何指定转换,以便
let angle = CGFloat.pi/3
layer.transform = ???
xx
值的情况下再次重新应用您的变换