Basic typography design system for iOS using Swift. Article link: http://www.popcornomnom.com/basic-typography-design-system-for-ios-using-swift/

FontManagerBasic+SwiftUI.swift

//
//  FontManager.swift
//
//  Created by http://www.popcornomnom.com
//  Copyright © 2019 Marharyta Lytvynenko. All rights reserved.
//

import UIKit
import SwiftUI

//MARK: - Font Parts
public extension UIFont {

    enum Family: String {
        case system = ".SFUIText" //".SFUI"
        case inter = "Inter"

        //easy to change default app fonts family
        static let defaultFamily = Family.inter
    }

    enum CustomWeight: String {
        case regular = "", medium, light, heavy, bold, semibold, black
    }

    enum Size: CGFloat {
        case h1 = 36, h2 = 28, h3 = 20
        case bodyL = 17, bodyM = 15, bodyS = 13
    }

    //put Family and Weight together
    private class func stringName(_ family: Family, _ weight: CustomWeight) -> String {
        /**
        Define incompatible family, weight here
        in this case set defaults compatible values
        */
        let fontWeight: String
        switch (family, weight) {
        case (.inter, .heavy): fontWeight = FontWeight.semibold.rawValue
        case (.inter, .light): fontWeight = "\(weight.rawValue)BETA"
        default:               fontWeight = weight.rawValue
        }
        let familyName = family.rawValue
        return fontWeight.isEmpty ? "\(familyName)" : "\(familyName)-\(fontWeight)"
    }
}

//MARK: - Initializers
extension UIFont {
    
    convenience init(_ size: FontSize, _ weight: FontWeight) {
        self.init(.defaultFamily, size, weight)
    }
    
    convenience init(_ family: FontFamily = .defaultFamily,
                     _ size: FontSize, _ weight: FontWeight) {
        self.init(name: stringName(family, weight), size: size.rawValue)!
    }
}

//MARK: - SwiftUI
@available(iOS 13.0, *) 
extension Font {
    
    init(_ size: FontSize, _ weight: FontWeight) {
        self.init(.defaultFamily, size, weight)
    }

    init(_ family: FontFamily = .defaultFamily,
                     _ size: FontSize, _ weight: FontWeight) {
        self.init(UIFont(family, size, weight))
    }
}

Basic typography design system for iOS using Swift and SwiftUI

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