How to convert a UIView to an image

you can use extension

extension UIImage {
    convenience init(view: UIView) {
        UIGraphicsBeginImageContext(view.frame.size)
        view.layer.render(in:UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        self.init(cgImage: image!.cgImage!)
    }
}

Here the swift 3/4 version :

extension UIImage {
    convenience init(view: UIView) {
        UIGraphicsBeginImageContext(view.frame.size)
        view.layer.render(in:UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        self.init(cgImage: image!.cgImage!)
    }
}

An extension on UIView should do the trick.

extension UIView {

    // Using a function since `var image` might conflict with an existing variable
    // (like on `UIImageView`)
    func asImage() -> UIImage {
        let renderer = UIGraphicsImageRenderer(bounds: bounds)
        return renderer.image { rendererContext in
            layer.render(in: rendererContext.cgContext)
        }
    }
}

Apple discourages using UIGraphicsBeginImageContext starting iOS 10 with the introduction of the P3 color gamut. UIGraphicsBeginImageContext is sRGB and 32-bit only. They introduced the new UIGraphicsImageRenderer API that is fully color managed, block-based, has subclasses for PDFs and images, and automatically manages the context lifetime. Check out WWDC16 session 205 for more details (image rendering begins around the 11:50 mark)

To be sure that it works on every device, use #available with a fallback to earlier versions of iOS:

extension UIView {

    // Using a function since `var image` might conflict with an existing variable
    // (like on `UIImageView`)
    func asImage() -> UIImage {
        if #available(iOS 10.0, *) {
            let renderer = UIGraphicsImageRenderer(bounds: bounds)
            return renderer.image { rendererContext in
                layer.render(in: rendererContext.cgContext)
            }
        } else {
            UIGraphicsBeginImageContext(self.frame.size)
            self.layer.render(in:UIGraphicsGetCurrentContext()!)
            let image = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            return UIImage(cgImage: image!.cgImage!)
        }
    }
}