Accessing content scaleFactor / multiplier?

Question

I am working on an iPhone 6 Plus, and getting the bounds of my UIView using:

let viewBounds = view.bounds // GIVES 736 x 414 (Points), WHICH IS RIGHT

Is there any way that I can get the multiplier (i.e. the @3x) that is used to convert the points into pixels. I was hoping that I could use:

let scaleFactor = view.contentScaleFactor // GIVES 1

But as you can see it always seems to return 1. I know that I can grab the screen size directly using preferredMode.size or nativeBounds but I am sure there was a way before to access the multiplier too?

// WHERE SCALE FACTOR WOULD BE 3
let yRes = viewBounds.height * scaleFactor // 736 x 3 = 2208
let xRes = viewBounds.width * scaleFactor //  414 x 3 = 1242

Answer 1

the UIView Class Reference documentation says about contentScaleFactor property:

(...) For system views, the value of this property may be 1.0 even on high resolution screens.

therefore that is not what you look for.

---

the actual scale factor can be read from the main screen, that will give you either 1.0, 2.0 or even 3.0:

let scale: CGFloat = UIScreen.main.scale // Swift3, Swift4.x
let scale: CGFloat = UIScreen.mainScreen().scale // Swift 2.x

or

CGFloat _scale = [[UIScreen mainScreen] scale]; // Obj-C

you can read more about the scale property in the UIScreen Class Reference.

Answer 2

swift 3.0

let scale = UIScreen.main.scale