Adding blur effect to background in swift

Question

I am setting a background image to view controller. But also i want to add blur effect to this background. How can I do this?

I am setting background with following

Answer 1

This one always keeps the right frame:

public extension UIView {

    @discardableResult
    public func addBlur(style: UIBlurEffect.Style = .extraLight) -> UIVisualEffectView {
        let blurEffect = UIBlurEffect(style: style)
        let blurBackground = UIVisualEffectView(effect: blurEffect)
        addSubview(blurBackground)
        blurBackground.translatesAutoresizingMaskIntoConstraints = false
        blurBackground.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
        blurBackground.topAnchor.constraint(equalTo: topAnchor).isActive = true
        blurBackground.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
        blurBackground.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
        return blurBackground
    }
}