Fonts.swift

//
//  Copyright (c) Microsoft Corporation. All rights reserved.
//  Licensed under the MIT License.
//

import UIKit

public final class MSFonts: NSObject {
    /// Bold 30pt - Does not scale automatically with Dynamic Type
    @objc public static let largeTitle = UIFont.systemFont(ofSize: 30, weight: .bold)
    /// Bold 26pt - Does not scale automatically with Dynamic Type
    @objc public static let title1 = UIFont.systemFont(ofSize: 26, weight: .bold)
    /// Semibold 22pt
    @objc public static var title2: UIFont { return preferredFont(forTextStyle: .title2, weight: .semibold) }
    /// Semibold 17pt
    @objc public static var headline: UIFont { return .preferredFont(forTextStyle: .headline) }
    @objc public static var headlineUnscaled: UIFont { return .preferredFont(forTextStyle: .headline, compatibleWith: UITraitCollection(preferredContentSizeCategory: .large)) }
    /// Regular 17pt
    @objc public static var body: UIFont { return .preferredFont(forTextStyle: .body) }
    @objc public static var bodyUnscaled: UIFont { return .preferredFont(forTextStyle: .body, compatibleWith: UITraitCollection(preferredContentSizeCategory: .large)) }
    /// Regular 15pt
    @objc public static var subhead: UIFont { return .preferredFont(forTextStyle: .subheadline) }
    /// Regular 13pt
    @objc public static var footnote: UIFont { return .preferredFont(forTextStyle: .footnote) }
    @objc public static var footnoteUnscaled: UIFont { return .preferredFont(forTextStyle: .footnote, compatibleWith: UITraitCollection(preferredContentSizeCategory: .large)) }
    /// Medium 15pt
    @objc public static var button1: UIFont { return preferredFont(forTextStyle: .subheadline, weight: .medium) }
    /// Medium 13pt
    @objc public static var button2: UIFont { return preferredFont(forTextStyle: .footnote, weight: .medium) }
    /// Medium 10pt - Does not scale automatically with Dynamic Type
    @objc public static let button3 = UIFont.systemFont(ofSize: 10, weight: .medium)
    /// Medium 15pt - Does not scale automatically with Dynamic Type
    @objc public static let button4 = UIFont.systemFont(ofSize: 15, weight: .medium)
    /// Regular 12pt
    @objc public static var caption1: UIFont { return .preferredFont(forTextStyle: .caption1) }
    /// Regular 11pt
    @objc public static var caption2: UIFont { return .preferredFont(forTextStyle: .caption2) }

    static func preferredFont(forTextStyle style: UIFont.TextStyle, weight: UIFont.Weight, size: CGFloat? = 0) -> UIFont {
        let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: style)
        let newDescriptor = descriptor.addingAttributes([.traits: [UIFontDescriptor.TraitKey.weight: weight]])
        let pointSize: CGFloat
        if let size = size, size > 0 {
            pointSize = size
        } else {
            pointSize = descriptor.pointSize
        }
        return UIFont(descriptor: newDescriptor, size: pointSize)
    }

    private override init() {
        super.init()
    }
}

@objc public enum MSTextStyle: Int, CaseIterable {
    case largeTitle
    case title1
    case title2
    case headline
    case headlineUnscaled
    case body
    case bodyUnscaled
    case subhead
    case footnote
    case footnoteUnscaled
    case button1
    case button2
    case button3
    case caption1
    case caption2

    public var font: UIFont {
        switch self {
        case .largeTitle:
            return MSFonts.largeTitle
        case .title1:
            return MSFonts.title1
        case .title2:
            return MSFonts.title2
        case .headline:
            return MSFonts.headline
        case .headlineUnscaled:
            return MSFonts.headlineUnscaled
        case .body:
            return MSFonts.body
        case .bodyUnscaled:
            return MSFonts.bodyUnscaled
        case .subhead:
            return MSFonts.subhead
        case .footnote:
            return MSFonts.footnote
        case .footnoteUnscaled:
            return MSFonts.footnoteUnscaled
        case .button1:
            return MSFonts.button1
        case .button2:
            return MSFonts.button2
        case .button3:
            return MSFonts.button3
        case .caption1:
            return MSFonts.caption1
        case .caption2:
            return MSFonts.caption2
        }
    }
}