What is the system font of iOS13?

Question

What is the iOS 13 system font?

Before iOS 13 I used SFUIDisplay font.

UIFont(name: ".SFUIDisplay-Light", size: UIFont.systemFontSize)

But on iOS 13 it doesn't work.

Answer 1

This bug is so BS. The only way to get around it is by using the systemFont(ofSize:weight:) method directly. AKA, you cannot get the system font using the method UIFont(name:size:), you ll just get Times New Roman for some funny reason. Apple devs must be messing with us. So for the original question above you must use the following:

UIFont(systemFont:UIFont.systemFontSize, weight: .light)

For my situation, I ran into this bug making an extension for UIFont to return the same font in a different size, which must work with custom and system fonts. In order for it to work on xcode 11 ios 13, I had to add a silly check to see if fontName contains ".SF".

extension UIFont {
    func forSize(_ pointSize: CGFloat) -> UIFont {
        if !fontName.contains(".SF"), let font = UIFont(name: fontName, size: pointSize) {
            return font
        }

        return UIFont.systemFont(ofSize: pointSize, weight: weight)
    }
}

Answer 2

If you are aiming to use the system font, you don't really have to worry about its name, you should let the system to do it for you.

let font = UIFont.systemFont(ofSize: UIFont.systemFontSize)

At this point, whenever the system font changes, it will automatically updated.

Moreover

I use a lot of custom fonts. I need to do it

Actually, you could do it without mentioning the font name in case you want to use the system font. For example, you could implement a function that returns the proper font as:

func getFont(name: String = "", size: CGFloat = UIFont.systemFontSize) -> UIFont {
    // system font
    let defaultFont = UIFont.systemFont(ofSize: UIFont.systemFontSize)

    if name.isEmpty {
        return defaultFont
    }

    return UIFont(name: name, size: size) ?? defaultFont
}

For using the system font, call it: getFont(). Otherwise, call it with mentioning the name of the font: getFont(name: ".SFUIDisplay-Light").

However, you might think of doing something like this to get the system font name and then use it:

let systemFontName = UIFont.systemFont(ofSize: UIFont.systemFontSize).fontName
getFont(name: systemFontName)

I'd say it's meaningless since the UIFont.systemFont automatically detects the system font name without the need of mentioning it.