How to get monospaced numbers in UILabel on iOS 9

A

8

38

At WWDC 2015, there was a session about the new “San Francisco” system font in iOS 9. It uses proportional number rendering instead of monospaced numbers by default when linked against the iOS 9 SDK. There is a convenient initializer on NSFont called NSFont.monospacedDigitsSystemFontOfSize(mySize weight:) that can be used to explicitly enable monospaced number display.

However I couldn't find the UIKit equivalent for this on UIFont.

Airla answered 15/6, 2015 at 20:46 Comment(5)

tried using a font descriptor in a playground, but this is crashing with EXC_BAD_ACCESS in Xcode 7 Beta: var fontDescriptor = UIFontDescriptor().fontDescriptorWithSymbolicTraits(.TraitMonoSpace) – Dorcia 17/6, 2015 at 9:15

I did manage to create a UIFontDescriptor with .TraitMonoSpace like you mentioned, however this seems not to be the solution to this issue, since I am actually not trying to assign a special monospaced font to the whole label, but to change it's digit rendering behavior so it renders numbers in a monospaced mode. – Airla 18/6, 2015 at 11:17

This got fixed with Xcode 7 beta 4. UIFont now has the same monospacedDigitsSystemFontOfSize:weight: method as NSFont. – Airla 13/8, 2015 at 15:53

That's not the spelling. It's monospacedDigitSystemFontOfSize:weight: (no 's' after Digit). – Faceharden 28/11, 2015 at 16:26

https://mcmap.net/q/275412/-ios-monospaced-custom-font See this answer. This works for any custom fonts. – Edifice 11/6, 2018 at 7:46

C

54

Handy UIFont extension:

extension UIFont {
    var monospacedDigitFont: UIFont {
        let newFontDescriptor = fontDescriptor.monospacedDigitFontDescriptor
        return UIFont(descriptor: newFontDescriptor, size: 0)
    }
}

private extension UIFontDescriptor {
    var monospacedDigitFontDescriptor: UIFontDescriptor {
        let fontDescriptorFeatureSettings = [[UIFontDescriptor.FeatureKey.featureIdentifier: kNumberSpacingType,
                                              UIFontDescriptor.FeatureKey.typeIdentifier: kMonospacedNumbersSelector]]
        let fontDescriptorAttributes = [UIFontDescriptor.AttributeName.featureSettings: fontDescriptorFeatureSettings]
        let fontDescriptor = self.addingAttributes(fontDescriptorAttributes)
        return fontDescriptor
    }
}

Usage with @IBOutlet properties:

@IBOutlet private var timeLabel: UILabel? {
    didSet {
        timeLabel.font = timeLabel.font.monospacedDigitFont
    }
}

Latest version on GitHub.

Columbarium answered 22/6, 2015 at 13:45 Comment(13)

Since I still believe this to be a bug or at least an oversight in the current API release I have filed this as a bug and published it on OpenRadar as rdar://21402564 – Airla 23/6, 2015 at 14:25

I wrote a UIFont extension that implements the missing functionality: gist.github.com/samuel-mellert/a0419641895ff4c2ba82 – Airla 26/6, 2015 at 15:12

That's a lot of code for something that will be desired quite common, I do hope there will be an update on this before iOS9 is final – Banderole 13/7, 2015 at 15:14

@SamuelMellert Yup, same here. – Modestamodeste 12/8, 2015 at 14:28

This got fixed with Xcode 7 beta 4. UIFont now has the same monospacedDigitsSystemFontOfSize:weight: method as NSFont. – Airla 13/8, 2015 at 15:52

@SamuelMellert Actually, Apple's version is currently limited to the system font only whereas this works for any font. – Modestamodeste 27/9, 2015 at 10:4

This also works on iOS < 9. Looks like all relevant API is 7.0+. – Bidle 6/10, 2015 at 3:39

Nice solution, It also doesn't break anything in iOS 8. I call the extension functions on viewDidLoad. – Guessrope 24/10, 2015 at 18:8

Thank you, @SamuelMellert. This info should be added to the answer. I was using Rudolf's code and it broke after I upgraded to Xcode 7.3 today. And it was pretty hard to debug; it only crashes when building for release. – Sarto 22/3, 2016 at 7:22

This solution also broke for me in Xcode 7.3 and only when building for release. However, in 'monospacedDigitFontDescriptor' if you print(fontDescriptor) before returning it, the extension works fine.... ¯\_(ツ)_/¯ – Cession 6/5, 2016 at 16:50

@Rudolf Adamkovic Can you do Objective-C version? – Ean 9/6, 2016 at 16:53

It's worth noting, so people don't bang their head against the wall, that this won't necessarily work for arbitrary fonts. If the font doesn't have monospaced digit support then the added feature attributes won't have any effect. – Elmore 22/7, 2018 at 16:15

Hat off! Works great with the custom font I was using. – Anyplace 19/4, 2021 at 9:4

H

58

This is now available in UIFont since iOS 9:

+ (UIFont *)monospacedDigitSystemFontOfSize:(CGFloat)fontSize weight:(CGFloat)weight NS_AVAILABLE_IOS(9_0);

eg:

[UIFont monospacedDigitSystemFontOfSize:42.0 weight:UIFontWeightMedium];

or in Swift:

UIFont.monospacedDigitSystemFont(ofSize: 42.0, weight: UIFontWeightMedium)

Hage answered 29/8, 2015 at 11:42 Comment(1)

@RudolfAdamkovic That is correct. Monospaced digits are feature of system font (San Francisco) in particular, not something UIFont provides universally. – Bugbee 5/4, 2017 at 6:25

C

54

Handy UIFont extension:

extension UIFont {
    var monospacedDigitFont: UIFont {
        let newFontDescriptor = fontDescriptor.monospacedDigitFontDescriptor
        return UIFont(descriptor: newFontDescriptor, size: 0)
    }
}

private extension UIFontDescriptor {
    var monospacedDigitFontDescriptor: UIFontDescriptor {
        let fontDescriptorFeatureSettings = [[UIFontDescriptor.FeatureKey.featureIdentifier: kNumberSpacingType,
                                              UIFontDescriptor.FeatureKey.typeIdentifier: kMonospacedNumbersSelector]]
        let fontDescriptorAttributes = [UIFontDescriptor.AttributeName.featureSettings: fontDescriptorFeatureSettings]
        let fontDescriptor = self.addingAttributes(fontDescriptorAttributes)
        return fontDescriptor
    }
}

Usage with @IBOutlet properties:

@IBOutlet private var timeLabel: UILabel? {
    didSet {
        timeLabel.font = timeLabel.font.monospacedDigitFont
    }
}