CALayer frame origin.y is flipped, 0 is at the bottom?

问题

When I Add a set the fram on a CALayer the origin.y is reversed, 0 is at the bottom of it super layer and increasing origin.y moves it up in its super layer. Is there something I did to cause this to be flipped? I would expect origin.y=0 to be the top, not the bottom.

Thanks,

回答1:

You can flip the coordinate system to behave like iOS like this...

layer.sublayerTransform = CATransform3DMakeScale(1.0f, -1.0f, 1.0f);

回答2:

my two cents for UIViewController and swift:

  override func viewDidLoad() {
        super.viewDidLoad()

        #if os(iOS)
        let layer = view.layer
        layer.sublayerTransform = CATransform3DMakeScale(1.0, -1.0, 1.0)
        #endif// no need under OSX. in this way we can use ONE parent controller for iOS and OSX ...
}

来源：https://stackoverflow.com/questions/5176737/calayer-frame-origin-y-is-flipped-0-is-at-the-bottom