UIタイポグラフィーの詳細 〜その2〜 – WWDC2020

// Getting emphasized text styles
// フォントウェイトの設定により強調させる

let label = UILabel()
label.text = "Ready. Set. Code."

if let descriptor = UIFontDescriptor
    .preferredFontDescriptor(withTextStyle: .title1)
    .withSymbolicTraits(.traitBold) {
    // 28 pt Bold on iOS
    label.font = .init(descriptor: descriptor, size: 0)
}

// Getting emphasized text styles
// boldを使用したテキストの強調サンプル

// AppKit
let descriptor = NSFontDescriptor
    .preferredFontDescriptor(forTextStyle: .body)
    .withSymbolicTraits(.bold)
// 13 pt Semibold on macOS
let emphasizedBodyFont = NSFont(descriptor: descriptor, size: 0)

// UIKit/Catalyst
if let descriptor = UIFontDescriptor
    .preferredFontDescriptor(withTextStyle: .body)
    .withSymbolicTraits(.traitBold) {
    // 17 pt Semibold on iOS
    let emphasizedBodyFont = UIFont(descriptor: descriptor, size: 0)
}

// SwiftUI
let emphasizedFootnoteFont = Font.footnote.bold() // 13 pt Semibold on iOS

// Getting tight/loose leading variant
// 適切なleading幅を設定し、コンテンツの可読性を向上させる

// AppKit
let descriptor = NSFontDescriptor.preferredFontDescriptor(forTextStyle: .headline)
    .withSymbolicTraits(.tightLeading) // Use .looseLeading for loose leading font
let tightLeadingFont = NSFont(descriptor: descriptor, size: 0) // 14 pt line height

// UIKit/Catalyst
if let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .title1)
    .withSymbolicTraits(.traitTightLeading) { // Use .traitLooseLeading for loose leading
    let tightLeadingFont = UIFont(descriptor: descriptor, size: 0) // 36 pt line height
}

// SwiftUI
// Use .loose for loose leading font
let tightLeadingFootnoteFont = Font.footnote.leading(.tight) // 16 pt line height on iOS

// Access system font designs
// Use .serif for New York, .monospaced for SF Mono
// .rounded を指定することで、丸みのあるフォントを設定可能

// AppKit
let descriptor = NSFontDescriptor.preferredFontDescriptor(forTextStyle: .body)
    .withDesign(.rounded)
let roundedBodyFont = NSFont(descriptor: descriptor, size: 0) // SF Pro Rounded

// UIKit/Catalyst
if let descriptor = UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body)
    .withDesign(.rounded) {
    let roundedBodyFont = UIFont(descriptor: descriptor, size: 0) // SF Pro Rounded
}

// SwiftUI
let roundedBodyFont = Font.system(.body, design: .rounded) // SF Pro Rounded

// Support Dynamic Type with custom font in UIKit

if let customFont = UIFont(name: "Charter-Roman", size: 17) {
    let bodyMetrics = UIFontMetrics(forTextStyle: .body)
    
    // Charter-Roman scaled relative to body text style
    // in different content size categories.
    let customFontScaledLikeBody = bodyMetrics.scaledFont(for: customFont)
    label.font = customFontScaledLikeBody
    label.adjustsFontForContentSizeCategory = true

    // Scaling constant 10 relative to body text style.
    let scaledValue = bodyMetrics.scaledValue(for: 10)
}

struct ContentView: View {
    let prose = "Apple provides two type families you can use in your iOS apps. San Francisco (SF). San Francisco is a sans serif type family that includes SF Pro, SF Pro Rounded, SF Mono, SF Compact, and SF Compact Rounded."
    @ScaledMetric(relativeTo: .body) var padding: CGFloat = 20

    var body: some View {
        VStack {
            Text("Typography")
                .font(.custom("Avenir-Medium", size: 34, relativeTo: .title))
            Text(prose)
                .font(.custom("Charter-Roman", size: 17))
                .padding(padding)
        }
    }
}

// Support Dynamic Type with custom fonts in SwiftUI

// Text with font Avenir-Roman, scaling relative to title text style.
Text("Typography").font(.custom("Avenir-Roman", size: 34, relativeTo: .title))

// Text with font Helvetica, scaling relative to body text style.
Text("Title").font(.custom("Helvetica", size: 17))

// Text with font Courier, always use fixed size, do not scale according to user setting.
Text("Fixed").font(.custom("Courier", fixedSize: 17))

// Constant 10, scaled relative to title text style.
@ScaledMetric(relativeTo: .title) private var spacing: CGFloat = 10.0