System font with high legibility features

Font+Features.swift

// From https://github.com/anonymouscamera/anonymous-camera/blob/b7ae19b07a476c0a8a54274fdaadd9e5ecd811d5/anonymous-camera/Helpers/Helpers.swift

extension UIFont {
    
    static func roundedSystemFont (ofSize fontSize : CGFloat, andWeight weight: UIFont.Weight) -> UIFont {
        let systemFont = UIFont.systemFont(ofSize: fontSize, weight: weight)
        
        var font: UIFont = systemFont
        
        if #available(iOS 13.0, *) {
            if let descriptor = systemFont.fontDescriptor.withDesign(.rounded) {
                font = UIFont(descriptor: descriptor, size: fontSize)
            }
        }
        
        return font
    }
    
    func fontWithFeature(key: Int, value:Int) -> UIFont {
        let originalDesc = self.fontDescriptor
        let features:[UIFontDescriptor.AttributeName: Any] = [
            UIFontDescriptor.AttributeName.featureSettings : [
                [
                    UIFontDescriptor.FeatureKey.featureIdentifier: key,
                    UIFontDescriptor.FeatureKey.typeIdentifier: value
                ]
            ]
        ]
        let newDesc = originalDesc.addingAttributes(features)
        return UIFont(descriptor: newDesc, size: 0.0)
    }
    
    func fontWithVerticallyCenteredColon() -> UIFont {
        return self.fontWithFeature(key: kStylisticAlternativesType, value: kStylisticAltThreeOnSelector)
    }
    
    func fontWithSlashedZero() -> UIFont {
        return self.fontWithFeature(key: kTypographicExtrasType, value: kSlashedZeroOnSelector)
    }
    
    func fontWithMonospacedNumbers() -> UIFont {
        return self.fontWithFeature(key: kNumberSpacingType, value: kMonospacedNumbersSelector)
    }
    
    func fontWithHighLegibility() -> UIFont {
        return self.fontWithFeature(key: kStylisticAlternativesType, value: kStylisticAltSixOnSelector)
    }
}