Register fonts from files. Useful especially for fonts in frameworks.

FontUtility.swift

public class FontsUtility {
  /**
  Call this at the app startup to register custom fonts and use them in the app.
  */
  public static func registerFonts() {
    let bundle = Bundle(for: FontsUtility.self)
    guard let path = bundle.path(forResource: "Info", ofType: "plist") else {
      print("[RegisterFonts] Failed to find Info.plist")
      return
    }
    guard let infoDict = NSDictionary(contentsOfFile: path) else {
      print("[RegisterFonts] Failed to load Info.plist")
      return
    }
    guard let fontsArray = infoDict["UIAppFonts"] as? Array<String> else {
      print("[RegisterFonts] Failed to load custom fonts array")
      return
    }
    fontsArray.forEach { registerFont(fontName: $0, bundle: bundle) }
  }
  
  static func registerFont(fontName: String, bundle: Bundle) {
    guard let fontPath = bundle.path(forResource: fontName, ofType: nil) else {
      print("[RegisterFont] Failed to get path for \(fontName)")
      return
    }
    let fontURL = URL(fileURLWithPath: fontPath)
    guard let fontData = try? Data(contentsOf: fontURL) else {
      print("[RegisterFont] Failed to load \(fontName) data")
      return
    }
    guard let provider = CGDataProvider(data: fontData as CFData) else {
      print("[RegisterFont] Failed to create data provider for \(fontName) data")
      return
    }
    let font = CGFont(provider)
    var error: Unmanaged<CFError>? = nil
    let result = CTFontManagerRegisterGraphicsFont(font, &error)
    if !result {
      print("[RegisterFont]\n\(error)")
    }
  }
}