let data = myString.data(using: .ascii, allowLossyConversion: false)
    let filter = CIFilter(name: "CICode128BarcodeGenerator")
    filter?.setValue(data, forKey: "inputMessage")
    let transformImage = filter!.outputImage!
    let theImage = UIImage(ciImage:transformImage)
    let imageData = UIImagePNGRepresentation(theImage)
    mailComposeVC.addAttachmentData(imageData!, mimeType: "image/png", fileName: "image")