How to generate a QR image in iOS app using swift

Question

Hi I am working on an iOS project i want to generate a customised QR code but have no idea how to do it. I am attaching a sample also.

i want to generate a QR Code Like this in Swift Language. Thanks

You could achieve the same using CIFilter, CGAffineTransform, code snippet in my answer below. Please mark as answered if it answers your query — Srikanth Balaji, Aug 29 '19 at 05:19
may be you can look here: https://stackoverflow.com/q/28801350/5575752 — Ronak Chaniyara, Aug 29 '19 at 06:27

bestiosdeveloper · Accepted Answer · 2022-12-14T04:43:09.027

Here is the code for generating the QR code with logo image in centre:

import UIKit
import EventKit
import CoreImage

class ViewController: UIViewController {

@IBOutlet weak var imageView: UIImageView!

  override func viewDidLoad() {
    super.viewDidLoad()

    guard let qrURLImage = URL(string: "https://www.thepramodkumar.com/")?.qrImage(using: #colorLiteral(red: 0.3490196078, green: 0.768627451, blue: 0.6823529412, alpha: 1), logo: #imageLiteral(resourceName: "logo")) else { return }
    
    imageView.image = qrURLImage
    
   }
}


extension URL {

   /// Creates a QR code for the current URL in the given color.
   func qrImage(using color: UIColor, logo: UIImage? = nil) -> UIImage? {
    
      guard let tintedQRImage = qrImage?.tinted(using: color) else {
         return nil
      }
    
      guard let logo = logo?.cgImage else {
         return UIImage(ciImage: tintedQRImage)
      }
    
      guard let final = tintedQRImage.combined(with: CIImage(cgImage: logo)) else {
        return UIImage(ciImage: tintedQRImage)
      }
    
    return UIImage(ciImage: final)
  }

  /// Returns a black and white QR code for this URL.
  var qrImage: CIImage? {
    guard let qrFilter = CIFilter(name: "CIQRCodeGenerator") else { return nil }
    let qrData = absoluteString.data(using: String.Encoding.ascii)
    qrFilter.setValue(qrData, forKey: "inputMessage")
    
    let qrTransform = CGAffineTransform(scaleX: 12, y: 12)
    return qrFilter.outputImage?.transformed(by: qrTransform)
  }
}

extension CIImage {
  /// Inverts the colors and creates a transparent image by converting the mask to alpha.
  /// Input image should be black and white.
  var transparent: CIImage? {
     return inverted?.blackTransparent
  }

  /// Inverts the colors.
  var inverted: CIImage? {
      guard let invertedColorFilter = CIFilter(name: "CIColorInvert") else { return nil }
    
    invertedColorFilter.setValue(self, forKey: "inputImage")
    return invertedColorFilter.outputImage
  }

  /// Converts all black to transparent.
  var blackTransparent: CIImage? {
      guard let blackTransparentFilter = CIFilter(name: "CIMaskToAlpha") else { return nil }
    blackTransparentFilter.setValue(self, forKey: "inputImage")
    return blackTransparentFilter.outputImage
  }

  /// Applies the given color as a tint color.
  func tinted(using color: UIColor) -> CIImage? {
     guard
        let transparentQRImage = transparent,
        let filter = CIFilter(name: "CIMultiplyCompositing"),
        let colorFilter = CIFilter(name: "CIConstantColorGenerator") else { return nil }
    
    let ciColor = CIColor(color: color)
    colorFilter.setValue(ciColor, forKey: kCIInputColorKey)
    let colorImage = colorFilter.outputImage
    
    filter.setValue(colorImage, forKey: kCIInputImageKey)
    filter.setValue(transparentQRImage, forKey: kCIInputBackgroundImageKey)
    
    return filter.outputImage!
  }
}

extension CIImage {

  /// Combines the current image with the given image centered.
  func combined(with image: CIImage) -> CIImage? {
    guard let combinedFilter = CIFilter(name: "CISourceOverCompositing") else { return nil }
    let centerTransform = CGAffineTransform(translationX: extent.midX - (image.extent.size.width / 2), y: extent.midY - (image.extent.size.height / 2))
    combinedFilter.setValue(image.transformed(by: centerTransform), forKey: "inputImage")
    combinedFilter.setValue(self, forKey: "inputBackgroundImage")
    return combinedFilter.outputImage!
  }
}

Github Repo : https://github.com/bestiosdeveloper/QACodeDemo

For live demo project you can find: https://github.com/bestiosdeveloper/QACodeDemo — bestiosdeveloper, Aug 29 '19 at 05:48
thanks for the answer firstly. one last thing i want to ask how will i shows those dots like in sample image. — Hasnain ahmad, Aug 29 '19 at 06:11

score 4 · Answer 2 · answered Aug 29 '19 at 05:09

func generateQRCode(from string: String) -> UIImage? {
                    let data = string.data(using: .ascii, allowLossyConversion: false)
                    let filter = CIFilter(name: "CIQRCodeGenerator")
                    filter?.setValue(data, forKey: "inputMessage")
                    let img = UIImage(cgImage: CIContext(options: nil).createCGImage((filter?.outputImage!)!, from: (filter?.outputImage!.extent)!)!)
                    return img
                }

score 3 · Answer 3 · answered Aug 29 '19 at 05:06

You could achieve the same using CIFilter, CGAffineTransform https://developer.apple.com/documentation/coreimage/cifilter https://developer.apple.com/documentation/coregraphics/cgaffinetransform

Sample code

func genQRCode(from input: String) -> UIImage? {

    let data = input.data(using: String.Encoding.ascii)

    if let filter = CIFilter(name: "CIQRCodeGenerator") {
        filter.setValue(data, forKey: "inputMessage")
        let transform = CGAffineTransform(scaleX: 3, y: 3)

        if let output = filter.outputImage?.transformed(by: transform) {
            return UIImage(ciImage: output)
        }
    }

    return nil 
}

let image = generateQRCode(from: "Sample code to generate QR")

How to generate a QR image in iOS app using swift

3 Answers3