Xcode 12b1 和 Swift 包：自定义字体

Question

我已经能够成功地使用 Xcode 12b1 和 Swift 5.3 在 Swift 包中提供一些图像和资产目录。在 Swift 包中使用自定义 .ttf 文件并没有那么幸运。

我在清单中加载一个 .ttf 文件，如下所示：

.target(
  name: "BestPackage",
  dependencies: [],
  resources: [
    .copy("Resources/Fonts/CustomFont.ttf"),
    .process("Resources/Colors.xcassets")
  ]
),

我注意到FontSwiftUI 中的类型没有初始化器来包含模块中的资产。例如，这有效：

static var PrimaryButtonBackgroundColor: SwiftUI.Color {
  Color("Components/Button/Background", bundle: .module)
}

但是，无法指定字体的来源。我希望将它加载到模块中会将它发送到目标中以供使用，但没有这样的运气：

static var PrimaryButtonFont: Font {
  Font.custom("CustomFont", size: 34)
}

这不会按预期加载字体。我正在研究使用 CoreText api 尝试诱使它加载，但我觉得应该有更简单的方法。有什么建议吗？

更新

仍然没有成功，但我能够证明字体确实在模块内

我编写了一个方法来从模块中获取可用的字体 URL，如下所示：

  static func fontNames() -> [URL] {
    let bundle = Bundle.module
    let filenames = ["CustomFont"]
    return filenames.map { bundle.url(forResource: $0, withExtension: "ttf")! }
  }

在运行时调用此方法并打印结果会产生以下结果：

font names: [file:///Users/davidokun/Library/Developer/CoreSimulator/Devices/AFE4ADA0-83A7-46AE-9116-7870B883DBD3/data/Containers/Bundle/Application/800AE766-FB60-4AFD-B57A-0E9F3EACCDB2/BestPackageTesting.app/BestPackage_BestPackage.bundle/CustomFont.ttf]

然后我尝试使用以下方法注册在运行时使用的字体：

extension UIFont {
  static func register(from url: URL) {
    guard let fontDataProvider = CGDataProvider(url: url as CFURL) else {
      print("could not get reference to font data provider")
      return
    }
    guard let font = CGFont(fontDataProvider) else {
      print("could not get font from coregraphics")
      return
    }
    var error: Unmanaged<CFError>?
    guard CTFontManagerRegisterGraphicsFont(font, &error) else {
      print("error registering font: \(error.debugDescription)")
      return
    }
  }
}

当我这样称呼它时：

fontNames().forEach { UIFont.register(from: $0) }

我收到此错误：

error registering font: Optional(Swift.Unmanaged<__C.CFErrorRef>(_value: Error Domain=com.apple.CoreText.CTFontManagerErrorDomain Code=105 "Could not register the CGFont '<CGFont (0x600000627a00): CustomFont>'" UserInfo={NSDescription=Could not register the CGFont '<CGFont (0x600000627a00): CustomFont>', CTFailedCGFont=<CGFont (0x600000627a00): CustomFont>}))

欢迎提出更多想法。

Answer 1

我设法使用 SPM 导入自定义字体，使用这个 SO 答案来帮助/sf/answers/2580972271/

这是我所做的。创建您的包并添加您的字体。这是我的Package.swift

// swift-tools-version:5.3
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "MyFonts",
    products: [
        .library(
            name: "MyFonts",
            targets: ["MyFonts"]),
    ],
    dependencies: [
    ],
    targets: [

        .target(
            name: "MyFonts",
            dependencies: [],
            resources: [.process("Fonts")]),
        .testTarget(
            name: "MyFontsTests",
            dependencies: ["MyFonts"]),
    ]
)

这是我的文件夹结构。我的所有字体都包含在一个名为 Fonts 的文件夹中。

在里面MyFonts.swift我做以下事情：

import Foundation // This is important remember to import Foundation

public let fontBundle = Bundle.module

这允许我访问包外的 Bundle。

接下来我将包添加到我的项目中。它是一个带有 AppDelegate 的 SwiftUI 项目。

• 导入我的字体
• 在didFinishLaunchingWithOptions检查，看是否字体文件可用（可选）
• 使用扩展名将字体添加到 UIFont。
• 打印字体以检查它们是否已安装（可选）

所以这是我的 AppDelegate：

import UIKit
import MyFonts

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        // This prints out the files that are stored in the MyFont bundle
        // Just doing this to check that the fonts are actually in the bundle
        if let files = try? FileManager.default.contentsOfDirectory(atPath: fontBundle.bundlePath ){
            for file in files {
                print(file)
            }
        }

        // This registers the fonts
        _ = UIFont.registerFont(bundle: fontBundle, fontName: "FiraCode-Medium", fontExtension: "ttf")
        _ = UIFont.registerFont(bundle: fontBundle, fontName: "FiraCode-Bold", fontExtension: "ttf")
        _ = UIFont.registerFont(bundle: fontBundle, fontName: "FiraCode-Light", fontExtension: "ttf")
        _ = UIFont.registerFont(bundle: fontBundle, fontName: "FiraCode-Regular", fontExtension: "ttf")
        _ = UIFont.registerFont(bundle: fontBundle, fontName: "FiraCode-Retina", fontExtension: "ttf")

        // This prints out all the fonts available you should notice that your custom font appears in this list
        for family in UIFont.familyNames.sorted() {
            let names = UIFont.fontNames(forFamilyName: family)
            print("Family: \(family) Font names: \(names)")
        }

        return true
    }

    // MARK: UISceneSession Lifecycle

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {}
}

// This extension is taken from this SO answer /sf/answers/2580972271/
extension UIFont {
    static func registerFont(bundle: Bundle, fontName: String, fontExtension: String) -> Bool {

        guard let fontURL = bundle.url(forResource: fontName, withExtension: fontExtension) else {
            fatalError("Couldn't find font \(fontName)")
        }

        guard let fontDataProvider = CGDataProvider(url: fontURL as CFURL) else {
            fatalError("Couldn't load data from the font \(fontName)")
        }

        guard let font = CGFont(fontDataProvider) else {
            fatalError("Couldn't create font from data")
        }

        var error: Unmanaged<CFError>?
        let success = CTFontManagerRegisterGraphicsFont(font, &error)
        guard success else {
            print("Error registering font: maybe it was already registered.")
            return false
        }

        return true
    }
}

然后ContentView你可以做这样的事情：

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack(spacing: 20) {
            Text("Hello San Francisco")
            Text("Hello FiraCode Medium").font(Font.custom("FiraCode-Medium", size: 16))
            Text("Hello FiraCode Bold").font(Font.custom("FiraCode-Bold", size: 16))
            Text("Hello FiraCode Light").font(Font.custom("FiraCode-Light", size: 16))
            Text("Hello FiraCode Regular").font(Font.custom("FiraCode-Regular", size: 16))
            Text("Hello FiraCode Retina").font(Font.custom("FiraCode-Retina", size: 16))
        }
    }
}

这给出了以下结果：

注意事项

我还没有在一个完整的 SwiftUI 应用程序中尝试过这个，但是如果你没有一个 AppDelegate ，你可以按照这里显示的教程来添加一个 AppDelegate。

显然，打印文件中的文件fontBundle和安装的字体是可选的。它们仅用于调试和确保您拥有正确的字体名称 文件名可能与您必须用于显示字体的字体名称有很大不同。请参阅我关于添加自定义字体的SO帖子：

更新

我想知道是否有可能创建一个包含在包中的函数并调用它来加载字体。显然是。

我更新到MyFonts.swift以下内容：

import Foundation
import UIKit

public func registerFonts() {
    _ = UIFont.registerFont(bundle: .module, fontName: "FiraCode-Medium", fontExtension: "ttf")
    _ = UIFont.registerFont(bundle: .module, fontName: "FiraCode-Bold", fontExtension: "ttf")
    _ = UIFont.registerFont(bundle: .module, fontName: "FiraCode-Light", fontExtension: "ttf")
    _ = UIFont.registerFont(bundle: .module, fontName: "FiraCode-Regular", fontExtension: "ttf")
    _ = UIFont.registerFont(bundle: .module, fontName: "FiraCode-Retina", fontExtension: "ttf")
}

extension UIFont {
    static func registerFont(bundle: Bundle, fontName: String, fontExtension: String) -> Bool {

        guard let fontURL = bundle.url(forResource: fontName, withExtension: fontExtension) else {
            fatalError("Couldn't find font \(fontName)")
        }

        guard let fontDataProvider = CGDataProvider(url: fontURL as CFURL) else {
            fatalError("Couldn't load data from the font \(fontName)")
        }

        guard let font = CGFont(fontDataProvider) else {
            fatalError("Couldn't create font from data")
        }

        var error: Unmanaged<CFError>?
        let success = CTFontManagerRegisterGraphicsFont(font, &error)
        guard success else {
            print("Error registering font: maybe it was already registered.")
            return false
        }

        return true
    }
}

这意味着我可以从 AppDelegate 中删除扩展名，并且我不必像在调用之前那样在 AppDelegate 中注册每种字体 registerFonts()

所以我didFinishLaunchingWithOptions现在看起来像这样：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

    // This registers the fonts
    registerFonts()

    return true
}

请记住，您仍然需要导入您的包。

Answer 2

Here is a simplified version of @Andrew's answer. I have tested this in a 100% SwiftUI app on iOS and macOS; it does not require UIKit. Fonts registered in this way can be accessed from other dependent packages.

func registerFont(_ name: String, fileExtension: String) {
    guard let fontURL = Bundle.module.url(forResource: name, withExtension: fileExtension) else {
        print("No font named \(name).\(fileExtension) was found in the module bundle")
        return
    }

    var error: Unmanaged<CFError>?
    CTFontManagerRegisterFontsForURL(fontURL as CFURL, .process, &error)
    print(error ?? "Successfully registered font: \(name)")
}

You should load your font and color assets into your package like this:

.target(
  name: "BestPackage",
  dependencies: [],
  resources: [
    .process("Resources")
  ]
),

From the docs:

If the given path represents a directory, Xcode applies the process rule recursively to each file in the directory.

If possible, use this rule instead of copy(_:).