Generate QR Code Swift 4.2

Example code QR code

1. Simple Generate QR Code

// @IBAction func bAction(_ sender: Any) {
//    if let myString = textField.text {
//        // first
//
//        // second
//        let data = myString.data(using: .ascii, allowLossyConversion: false)
//        guard let filter = CIFilter(name: "CIQRCodeGenerator") else { return }
//        filter.setValue(data, forKey: "inputMessage")
//
//        let qrTransform = CGAffineTransform(scaleX: 12, y: 12)
//        guard let qrImage = filter.outputImage?.transformed(by: qrTransform) else { return }
//        let img = UIImage(ciImage: qrImage)
//        imageView.image = img
//    }
// }


2.  Generate Qr Code with Image (image inside QR Code)

//    @IBAction func bAction(_ sender: Any) {
//        if let myString = textField.text {
//            let data = myString.data(using: .ascii, allowLossyConversion: false)
//            guard let filter = CIFilter(name: "CIQRCodeGenerator") else { return }
//            filter.setValue(data, forKey: "inputMessage")
//            filter.setValue("Q", forKey: "inputCorrectionLevel")
//            
//            qrCodeImage = filter.outputImage
//            
//            let scaleX = imageView.frame.size.width / qrCodeImage.extent.size.width
//            let scaleY = imageView.frame.size.height / qrCodeImage.extent.size.height
//            
//            let transformedImage = qrCodeImage.transformed(by: CGAffineTransform(scaleX: scaleX, y: scaleY))
//            imageView.image = UIImage(ciImage: transformedImage)
//            
//            // mini image
//            let image = UIImage(named: "smallImage")
//            let overlayImageView = UIImageView(image: image)
//            overlayImageView.frame = CGRect(x: 0, y: 0, width: 50, height: 50)
//            overlayImageView.translatesAutoresizingMaskIntoConstraints = false
//            overlayImageView.clipsToBounds = true
//            overlayImageView.contentMode = UIView.ContentMode.scaleAspectFit
//            
//            // subView
//            let subview = UIView(frame: CGRect(x: 0, y: 0, width: 60, height: 60))
//            subview.backgroundColor = UIColor.white
//            subview.layer.cornerRadius = subview.frame.width / 2
//            subview.layer.borderColor = UIColor.gray.cgColor
//            subview.layer.borderWidth = 2
//            subview.center = CGPoint(x: imageView.frame.size.width / 2, y: imageView.frame.size.height / 2)
//            
//            subview.addSubview(overlayImageView)
//            
//            imageView.addSubview(subview)
//            
//            // constraint image
//            
//            let centerXConst = NSLayoutConstraint(item: overlayImageView, attribute: .centerX, relatedBy: .equal, toItem: subview, attribute: .centerX, multiplier: 1, constant: 0)
//            let centerYConst = NSLayoutConstraint(item: overlayImageView, attribute: .centerY, relatedBy: .equal, toItem: subview, attribute: .centerY, multiplier: 1, constant: 0)
//            NSLayoutConstraint.activate([centerXConst, centerYConst])
//            
//            // constraint view
//            
//            let centerXCons = NSLayoutConstraint(item: subview, attribute: .centerX, relatedBy: .equal, toItem: imageView, attribute: .centerX, multiplier: 1, constant: 0)
//            let centerYCons = NSLayoutConstraint(item: subview, attribute: .centerY, relatedBy: .equal, toItem: imageView, attribute: .centerY, multiplier: 1, constant: 0)
//            NSLayoutConstraint.activate([centerXCons, centerYCons])
//        }
//    }


Full code:

import UIKit

class GenerateQrCodeViewController: UIViewController {
    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var textField: UITextField!
    
    var qrCodeImage: CIImage!
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    @IBAction func bAction(_ sender: Any) {
        if let myString = textField.text {
            let data = myString.data(using: .ascii, allowLossyConversion: false)
            guard let filter = CIFilter(name: "CIQRCodeGenerator") else { return }
            filter.setValue(data, forKey: "inputMessage")
            filter.setValue("Q", forKey: "inputCorrectionLevel")
            
            qrCodeImage = filter.outputImage
            
            let scaleX = imageView.frame.size.width / qrCodeImage.extent.size.width
            let scaleY = imageView.frame.size.height / qrCodeImage.extent.size.height
            
            let transformedImage = qrCodeImage.transformed(by: CGAffineTransform(scaleX: scaleX, y: scaleY))
            imageView.image = UIImage(ciImage: transformedImage)
            
            // mini image
            let image = UIImage(named: "smallImage")
            let overlayImageView = UIImageView(image: image)
            overlayImageView.frame = CGRect(x: 0, y: 0, width: 50, height: 50)
            overlayImageView.translatesAutoresizingMaskIntoConstraints = false
            overlayImageView.clipsToBounds = true
            overlayImageView.contentMode = UIView.ContentMode.scaleAspectFit
            
            // subView
            let subview = UIView(frame: CGRect(x: 0, y: 0, width: 60, height: 60))
            subview.backgroundColor = UIColor.white
            subview.layer.cornerRadius = subview.frame.width / 2
            subview.layer.borderColor = UIColor.gray.cgColor
            subview.layer.borderWidth = 2
            subview.center = CGPoint(x: imageView.frame.size.width / 2, y: imageView.frame.size.height / 2)
            
            subview.addSubview(overlayImageView)
            
            imageView.addSubview(subview)
            
            // constraint image
            
            let centerXConst = NSLayoutConstraint(item: overlayImageView, attribute: .centerX, relatedBy: .equal, toItem: subview, attribute: .centerX, multiplier: 1, constant: 0)
            let centerYConst = NSLayoutConstraint(item: overlayImageView, attribute: .centerY, relatedBy: .equal, toItem: subview, attribute: .centerY, multiplier: 1, constant: 0)
            NSLayoutConstraint.activate([centerXConst, centerYConst])
            
            // constraint view
            
            let centerXCons = NSLayoutConstraint(item: subview, attribute: .centerX, relatedBy: .equal, toItem: imageView, attribute: .centerX, multiplier: 1, constant: 0)
            let centerYCons = NSLayoutConstraint(item: subview, attribute: .centerY, relatedBy: .equal, toItem: imageView, attribute: .centerY, multiplier: 1, constant: 0)
            NSLayoutConstraint.activate([centerXCons, centerYCons])
        }
    }
}