How can you scan a UIImage for a QR code using Swift

Question

I'm trying to read a QR code from a static image using Swift.

I can easily read it using a video source although it seems to be very different for images and I can't find too many resources online for this.

Any help appreciated, thanks.

Answer 1

func readQRCode(from image: UIImage) -> Result<String, QRReadingError> {
    guard let ciImage = CIImage(image: image) else {
        print("Couldn't create CIImage")
        return .failure(.generic)
    }

    guard let detector = CIDetector(
        ofType: CIDetectorTypeQRCode,
        context: nil,
        options: [CIDetectorAccuracy: CIDetectorAccuracyHigh]
    ) else {
        print("Detector not intialized")
        return .failure(.generic)
    }
    let features = detector.features(in: ciImage)
    let qrCodeFeatures = features.compactMap { $0 as? CIQRCodeFeature }
    guard let qrCode = qrCodeFeatures.first?.messageString else {
        print("No QR code found in the image")
        return .failure(.qrCodeNotFoundInImage)
    }
    return .success(qrCode)
}

enum QRReadingError: Error {
    case generic
    case qrCodeNotFoundInImage
}