extension UIImage {

convenience init?(barCodeText: String) {
    let data = barCodeText.data(using: .ascii)
    let filter = CIFilter(name: "CICode128BarcodeGenerator")!
    filter.setValue(data, forKey: "inputMessage")
    let transform = CGAffineTransform(scaleX: 3, y: 3)
    if let output = filter.outputImage?.transformed(by: transform) {
        print("output.extent", output.extent)
        self.init(ciImage: output)
    } else {
        return nil
    }
}