URL extension to generate a QR code from the URL itself. Ready for Swift 5

URL+QR.swift

//
//  URL+QR.swift
//  URL extension to generate QR code from an URL
//
//  Created by Adolfo Vera Blasco on 29/03/2019.
//  Copyright © 2019 Adolfo Vera Blasco. All rights reserved.
//

import UIKit
import CoreImage
import Foundation

extension URL
{
    // Código QR de la imagen
    var qrImage: UIImage?
    {
        return generateQR()
    }
    
    /**
        Crea un código QR de esta `URL`
     */
    func generateQR() -> UIImage?
    {
        guard let data = self.absoluteString.data(using: .isoLatin1),
              let qrFilter = CIFilter(name: "CIQRCodeGenerator")
        else
        {
            return nil
        }
        
        qrFilter.setValue(data, forKey: "inputMessage")
        
        if var qrCIImage = qrFilter.outputImage
        {
            let transformation = CGAffineTransform(scaleX: 20.0, y: 20.0)
            qrCIImage = qrCIImage.transformed(by: transformation)
      
            let context = CIContext(options: nil)
            let cgImage = context.createCGImage(qrCIImage, from: qrCIImage.extent)
            
            return UIImage(cgImage: cgImage!)
        }
        
        return nil
    }
}