What is the definitive iPhone X corner radius? I've been experimenting and have found no conclusive corner radius for the iPhone X.


Some sources, such as iPhone X Screen Demystified - PaintCode, say its 40pts.
Some say it's 44, like UI Design for iPhone X: Top Elements and the Notch - Max Rudberg.


Using Xcode, I created a circle with a width and length of 80 (so radius 40), and put it in the top left corner of the iPhone X (so x and y are zero), there is a tiny white gap between the circle and the the edge of the screen, which you can see here:



I also tried another method, doing this with a button:

button.frame.size.height = 812
button.frame.size.width = 375
button.layer.cornerRadius = 40
button.center = self.view.center


With this I am left with:




So the question is, what is the real corner radius? Or what is going on with Xcode?
iPhone X corners do not have a conclusive corner radius. They're not normal arcs, they are ‘continuous corners’.
You can't replicate these with a simple .cornerRadius, and you also can't use Apple's own continuous corners, since that's a private API.

CALayer on iOS 11 has a private &quot;continuousCorners&quot; property, which is what powers many rounded corners in SpringBoard – and likely more! Now I'm jealous.


https://twitter.com/argentumko/status/955773459463790592
The closest you can get without your own implementation is UIBezierPath's rounded rectangle drawing, which uses _continuousRoundedRectBezierPath.