CODEWITHSUNDEEP
iosswiftios12
Oleg Gordiichuk
Oleg Gordiichuk

Reputation: 15512

Issue with CIQRCodeGenerator in CIFilter

I am updating existing app to support iOS 12 and strange issue with CIFilter appears.

This is simple class with one function generate():

class QRGenerator {
    static func generate(from string: String) -> UIImage? {
        let context = CIContext()
        let data = string.data(using: String.Encoding.ascii)

        if let filter = CIFilter(name: "CIQRCodeGenerator") {
            filter.setValue(data, forKey: "inputMessage")
            let transform = CGAffineTransform(scaleX: 7, y: 7)
            if let output = filter.outputImage?.transformed(by: transform), let cgImage = context.createCGImage(output, from: output.extent) {
                return UIImage(cgImage: cgImage)
            }
        }
        return nil
    }
}

This class work perfectly until iOS 12. Now in line if let filter = CIFilter(name: "CIQRCodeGenerator") I always receive nil.

I have spend some time on the Apple documentation but do not find any useful information about this issue.

Upvotes: 5

Views: 3739

Answers (3)

Prajapati Ramesh
Prajapati Ramesh

Reputation: 114

In Swift 5

class QRGenerator {
    static func generate(from string: String) -> UIImage? {
        let data = string.data(using: .ascii, allowLossyConversion: false)
        let filter = CIFilter(name: "CIQRCodeGenerator")
        filter?.setValue(data, forKey: "inputMessage")
        
        return UIImage(ciImage: (filter?.outputImage)!)
    }
}

call this function

myImageView.image = QRGenerator.generate(from: "Stackoverflow")

Upvotes: 1

Sergio
Sergio

Reputation: 1932

It happens to me too, I also tried generating the QR with an external library like QRcode https://github.com/aschuch/QRCode but the image of the QR is always nil.

It's nil when I install the app in emulators with iOS 12.0 (16A5308d) from Xcode 10.0 beta 2.

But when I install it in a physical device iPhone SE with iOS 12 beta 4 (16A5339e) from the same Xcode (10.0 beta 2), the QR is generated with no problem at all.

I also tried with an emulated iPhone SE with iOS 11.4 (15F79) from the same Xcode (10.0 beta 2) and works perfect.

Upvotes: 1

user1046037
user1046037

Reputation: 17735

I know very little about CIFilters, but may be you could try to get all possible filter names:

let allFiltersNames = CIFilter.filterNames(inCategories: nil)

I couldn't spot one that matches CIQRCodeGenerator but may be there is some other filter with a different name that would meet your needs.

Upvotes: 0

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