swift generate a qrcode [duplicate] - swift

Question

This question already has answers here:
What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean?
(16 answers)
Closed 2 years ago.
I tried to generate a qrcode, but it has error
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
let myString = "ggigiuui"
let data = myString.data(using: .ascii, allowLossyConversion: false)
let filter = CIFilter(name: "CIQRCodeGenerator")
filter?.setValue(data, forKey: "inputMessage")
let img = UIImage(ciImage: (filter?.outputImage)!)
qponImage.image = img

Answer 1

I have used the following code, and it is working perfectly.Where self.imgQRCode is the imageview on which you want to display QR.
func generateQRCode(from string: String) -> UIImage?
{
let data = string.data(using: String.Encoding.ascii)
if let filter = CIFilter(name: "CIQRCodeGenerator")
{
filter.setValue(data, forKey: "inputMessage")
guard let qrImage = filter.outputImage else {return nil}
let scaleX = self.imgQRCode.frame.size.width / qrImage.extent.size.width
let scaleY = self.imgQRCode.frame.size.height / qrImage.extent.size.height
let transform = CGAffineTransform(scaleX: scaleX, y: scaleY)
if let output = filter.outputImage?.transformed(by: transform)
{
return UIImage(ciImage: output)
}
}
return nil
}

Answer 2

Please try this,
func generateQRCode(from string: String) -> UIImage? {
let data = string.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
}

Answer 3

This is how you can generate a QRCode and display in UIImageView
first of all create new Cocoa Touch Class .swift file and import these two framework:
import UIKit
import CoreImage
and the second step you just need to add the extension of URL and CIImage on the same .swift file.
extensions :
extension URL {
/// Creates a QR code for the current URL in the given color.
func qrImage(using color: UIColor, logo: UIImage? = nil) -> CIImage? {
let tintedQRImage = qrImage?.tinted(using: color)
guard let logo = logo?.cgImage else {
return tintedQRImage
}
return tintedQRImage?.combined(with: CIImage(cgImage: logo))
}
/// 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!
}
/// 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!
}
}
and the third step you have to bund the outlet of your imageview in which you want to display generated QRCode.
your ViewController.swift file something like this.
// desired color of QRCode
let OrangeColor = UIColor(red:0.93, green:0.31, blue:0.23, alpha:1.00)
// app logo or whatever UIImage you want to set in the center.
let Logo = UIImage(named: "logo_which_you_want_to_set_in_the center_of_the_QRCode")!
#IBOutlet weak var imgQRImage: UIImageView!
and last and final step add the QRCode to imgQRImage and put the code in your viewDidLoad()
override func viewDidLoad() {
super.viewDidLoad()
let QRLink = "https://www.peerbits.com/"
guard let qrURLImage = URL(string: QRLink)?.qrImage(using: self.OrangeColor, logo: self.Logo)else{return}
self.imgQRImage.image = UIImage(ciImage: qrURLImage)
}

Answer 4

As mention in docs we can use CIQRCodeGenerator
func qrCode(_ outputSize: CGSize) -> UIImage?
{
if let data = data(using: .isoLatin1),
let outputImage = CIFilter(
name: "CIQRCodeGenerator",
parameters: [
"inputMessage": data,
"inputCorrectionLevel": "Q"
]
)?.outputImage {
let size: CGRect = outputImage.extent.integral
let format = UIGraphicsImageRendererFormat()
format.scale = UIScreen.main.scale
return UIGraphicsImageRenderer(size: output, format: format)
.image { _ in
outputImage
.transformed(
by: .init(
scaleX: outputSize.width/size.width,
y: outputSize.height/size.height
)
)
.uiimage
.draw(in: .init(origin: .zero, size: outputSize))
}
} else {
return nil
}
}
extension CIImage {
var uiimage: UIImage {
.init(ciImage: self)
}
}
this is bit modified version of this post
and in case u need to parse qr code image for content
func decodeQRCode(_ image: UIImage?) -> [CIQRCodeFeature]? {
if let image = image,
let ciImage = CIImage(image: image) {
let context = CIContext()
var options: [String: Any] = [
CIDetectorAccuracy: CIDetectorAccuracyHigh
]
let qrDetector = CIDetector(
ofType: CIDetectorTypeQRCode,
context: context,
options: options
)
if ciImage.properties.keys
.contains((kCGImagePropertyOrientation as String)) {
options = [
CIDetectorImageOrientation: ciImage
.properties[(kCGImagePropertyOrientation as String)] as Any
]
} else {
options = [CIDetectorImageOrientation: 1]
}
let features = qrDetector?.features(in: ciImage, options: options)
return features?
.compactMap({ $0 as? CIQRCodeFeature })
}
return nil
}
}