动态字体体验入门

3:53 - Built-in text styles with SwiftUI

// Use built-in text styles with SwiftUI

import SwiftUI

struct ContentView: View {

    var body: some View {
        Text("Hello, World!")
            .font(.title)
    }

}

4:06 - Built-in text styles in UIKit

// Built-in text styles in UIKit

import UIKit

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let label = UILabel(frame: .zero)
        setupConstraints()
        label.text = "Hello, World!"
        label.adjustsFontForContentSizeCategory = true
        label.font = .preferredFont(forTextStyle: .title1)
        label.numberOfLines = 0
        
        self.view.addSubview(label)
    }
}

7:20 - Dynamic layout in SwiftUI

// Dynamic layout in SwiftUI

import SwiftUI

struct FigureCell: View {
    @Environment(\.dynamicTypeSize) 
    private var dynamicTypeSize: DynamicTypeSize
    
    var dynamicLayout: AnyLayout { 
        dynamicTypeSize.isAccessibilitySize ?
        AnyLayout(HStackLayout()) : AnyLayout(VStackLayout())
    }
    
    let systemImageName: String
    let imageTitle: String
    
    var body: some View {
        dynamicLayout {
            FigureImage(systemImageName: systemImageName)
            FigureTitle(imageTitle: imageTitle)
        }
    }
}

7:52 - Dynamic layout in SwiftUI

// Dynamic layout in SwiftUI

import SwiftUI

struct FigureContentView: View {
    @Environment(\.dynamicTypeSize) 
    private var dynamicTypeSize: DynamicTypeSize
    
    var dynamicLayout: AnyLayout {
        dynamicTypeSize.isAccessibilitySize ?
        AnyLayout(VStackLayout(alignment: .leading)) : AnyLayout(HStackLayout(alignment: .top))
    }
    
    var body: some View {
        dynamicLayout {
            FigureCell(systemImageName: "figure.stand", imageTitle: "Standing Figure")
            FigureCell(systemImageName: "figure.wave", imageTitle: "Waving Figure")
            FigureCell(systemImageName: "figure.walk", imageTitle: "Walking Figure")
            FigureCell(systemImageName: "figure.roll", imageTitle: "Rolling Figure")
        }
    }
}

8:20 - Dynamic layout in UIKit

// Dynamic layout in UIKit

import UIKit

class ViewController: UIViewController {
    private var mainStackView: UIStackView = UIStackView()
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        NotificationCenter.default.addObserver(self, selector: #selector(textSizeDidChange(_:)), name: UIContentSizeCategory.didChangeNotification, object: nil)
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupStackView()
    }

    @objc private func textSizeDidChange(_ notification: Notification?) {
        let isAccessibilityCategory = self.traitCollection.preferredContentSizeCategory.isAccessibilityCategory
        mainStackView.axis = isAccessibilityCategory ? .vertical : .horizontal
        setupConstraints()
    }
}

10:12 - Scale inline images with SwiftUI

// Inline images in SwiftUI

import SwiftUI

struct ContentView: View {

    var body: some View {
        List {
            FigureListCell(figureName: "Standing Figure",
                systemImage: "figure.stand")
            FigureListCell(figureName: "Rolling Figure",
                  systemImage: "figure.roll")
            FigureListCell(figureName: "Waving Figure",
                systemImage: "figure.wave")
            FigureListCell(figureName: "Walking Figure",
                systemImage: "figure.walk")
        }
    }

}

10:30 - Scale inline images with UIKit

// Inline images in UIKit

func attributedStringWithImage(systemImageName: String, imageTitle: String) ->  
    NSAttributedString {
    let attachment = NSTextAttachment()
    attachment.image = UIImage(systemName: systemImageName)
    
    let attachmentAttributedString = NSMutableAttributedString(attachment: attachment)
    attachmentAttributedString.append(NSAttributedString(string: imageTitle))
    
    return attachmentAttributedString
}

11:05 - Scale images in SwiftUI

// Scaling images in SwiftUI

import SwiftUI

struct ContentView: View {
    @ScaledMetric var imageWidth = 125.0
    var body: some View {
        VStack {
            Image("Spatula")
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(width: imageWidth)
            Text("Grill Party!")
                .frame(alignment: .center)
        }
    }
}

11:38 - Scale symbols with UIKit

// Symbol configuration in UIKit

import UIKit

func imageWithBodyConfiguration(systemImageName: String) -> UIImage? {
  let imageConfiguration = UIImage.SymbolConfiguration(textStyle: .body)
  let configuredImage = UIImage(systemName: systemImageName, withConfiguration: imageConfiguration)
  return configuredImage
}

13:15 - Add large content viewer support with SwiftUI

// Large content viewer support in SwiftUI

import SwiftUI

struct FigureBar: View {
    @Binding var selectedFigure: Figure
    
    var body: some View {
       HStack {
            ForEach(Figure.allCases) { figure in
                FigureButton(figure: figure, isSelected: selectedFigure == figure)
                    .onTapGesture {
                        selectedFigure = figure
                    }
                    .accessibilityShowsLargeContentViewer {
                        Label(figure.imageTitle, systemImage: figure.systemImage)
                    }
            }
        }
    }
}

13:45 - Add large content viewer support with UIKit

// Large content viewer support in UIKit

import UIKit

class FigureCell: UIStackView {
    var systemImageName: String!
    var imageTitle: String!
    var imageLabel: UILabel!
    var titleImageView: UIImageView!
    
    required init(coder: NSCoder) {
        super.init(coder: coder)
        setupFigureCell()
    }
    
    init(systemImageName: String, imageTitle: String) {
        super.init(frame: .zero)
        
        self.systemImageName = systemImageName
        self.imageTitle = imageTitle
        
        setupFigureCell()

        self.addInteraction(UILargeContentViewerInteraction())
        self.showsLargeContentViewer = true
        self.largeContentImage = UIImage(systemName: systemImageName)
        self.scalesLargeContentImage = true
        self.largeContentTitle = imageTitle
    }
}