如何增加 Swift3 中的 UIButton 图像大小?

How to increase the UIButton Image size in Swift3?

我正在使用 UIButton 的默认 UIImage 属性 来设置背景图像。我已成功完成,但 image 似乎变小了。如何增加UIButton中的图像尺寸?

    let viewForNavigation = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 40))
    viewForNavigation.backgroundColor = UIColor.clear
    let backbutton = UIButton(frame: CGRect(x: 0, y: 8, width: 320, height: 20))
    backbutton.setImage(UIImage(named: "back_button"), for: UIControlState.normal)
    backbutton.imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right:10)
    backbutton.contentHorizontalAlignment = .left
    backbutton.titleEdgeInsets = UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 0)
    backbutton.titleLabel!.font = UIFont().robotoMedium(withFontSize: 20)
    backbutton.setTitle(title, for: .normal)

    backbutton.setTitleColor(UIColor.black, for: UIControlState.normal)
    backbutton.addTarget(self, action: #selector(exitViewController), for: UIControlEvents.touchUpInside)
    viewForNavigation.addSubview(backbutton)
    let rightBarButton = UIBarButtonItem(customView: viewForNavigation)
    self.navigationItem.leftBarButtonItem = rightBarButton

我认为您选择了错误尺寸的后退按钮图像,请使用下图作为后退按钮:

输出