QR Code inspector app for macOS

ContentView.swift

import SwiftUI
import AppKit
internal import UniformTypeIdentifiers

struct ContentView: View {
  @State var isPresented: Bool = false
  @State var image: Data?
  @State var message: String = ""

  var body: some View {
    VStack {
      if let imageData = image {
        if let ns = NSImage(data: imageData) {
          Image(nsImage: ns)
            .resizable()
            .frame(width: 200, height: 200)
        }
      }

      if message.count > 0 {
        VStack {
          Text(message)
            .selectionDisabled(false)
          Button(action: {
            let pasteboard = NSPasteboard.general
            pasteboard.clearContents()
            pasteboard.setString(message, forType: .string)
          }) {
            HStack {
              Text("Copy")
            }
          }
        }
      }

      Button(action: {
        isPresented = true
      }) {
        HStack {
          Text("Choose file")
        }
        .fileImporter(isPresented: $isPresented, allowedContentTypes: [.image], onCompletion: { result in
          switch result {
          case .success(let url):
            readFile(url)
          case .failure:
          }
        })
      }
    }
  }

  func readFile(_ url: URL) {
    message = "No QR Code found"
    do {
      if url.startAccessingSecurityScopedResource() {
        image = try Data(contentsOf: url)
        let context = CIContext()
        let options: [String: Any] = [CIDetectorAccuracy: CIDetectorAccuracyHigh]
        guard let detector = CIDetector(ofType: CIDetectorTypeQRCode, context: context, options: options) else {
          return
        }
        if let data = image {
          if let ciImage = CIImage(data: data) {
            let features = detector.features(in: ciImage)
            for feature in features {
              if let qrCodeFeature = feature as? CIQRCodeFeature,
                 let messageString = qrCodeFeature.messageString {
                message = messageString
              }
            }

          }
        }
      }
    } catch {
    }
    url.stopAccessingSecurityScopedResource()
  }
}