backbutton.swift

/ back 버튼 여백 적용 메소드
extension UIImage {
    func imageWithInsets(insets: UIEdgeInsets) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(
            CGSize(width: self.size.width + insets.left + insets.right,
                   height: self.size.height + insets.top + insets.bottom),
            false, self.scale)
        guard UIGraphicsGetCurrentContext() != nil else { return UIImage() }
        let origin = CGPoint(x: insets.left, y: insets.top)
        self.draw(at: origin)
        guard let imageWithInsets = UIGraphicsGetImageFromCurrentImageContext() else { return UIImage() }
        UIGraphicsEndImageContext()
        return imageWithInsets
    }
}

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

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

        // back Button
        let backImage = #imageLiteral(resourceName: "left_white").imageWithInsets(insets: UIEdgeInsets(top: 0, left: 8, bottom: 0, right: 0))
        let navbarAppearace = UINavigationBar.appearance()

        navbarAppearace.backIndicatorTransitionMaskImage = backImage
        navbarAppearace.backIndicatorImage = backImage
        navbarAppearace.barStyle = .black
    }
}