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자습서: 사진의 콘텐츠를 사용하여 몰입형 리더를 시작하는 iOS 앱 만들기(Swift)

몰입형 판독기는 읽기 이해도를 향상시키기 위해 검증된 기술을 구현하는 포괄적으로 설계된 도구입니다.

Azure AI 비전 Read API는 Microsoft의 최신 인식 모델을 사용하여 이미지의 텍스트 콘텐츠를 감지하고, 식별된 텍스트를 머신에서 읽을 수 있는 문자 스트림으로 변환합니다.

이 자습서에서는 iOS 앱을 처음부터 빌드하고, Immersive Reader SDK를 사용하여 Read API와 Immersive Reader를 통합합니다. 이 자습서의 전체 작업 샘플은 GitHub에서 제공됩니다.

필수 구성 요소

Xcode 프로젝트 만들기

Xcode에서 새 프로젝트를 만듭니다.

새 Xcode 프로젝트 만들기 화면의 스크린샷.

단일 보기 앱을 선택합니다.

단일 보기 앱을 선택하는 템플릿 갤러리의 스크린샷.

SDK CocoaPod 가져오기

몰입형 리더 SDK를 사용하는 가장 쉬운 방법은 CocoaPods를 사용하는 것입니다. Cocoapods를 통해 설치하려면 다음을 수행합니다.

  1. Cocoapods 설치 가이드를 따릅니다.

  2. Xcode 프로젝트의 루트 디렉터리에서 pod init를 실행하여 Podfile을 만듭니다.

  3. pod 'immersive-reader-sdk', :path => 'https://github.com/microsoft/immersive-reader-sdk/tree/master/iOS/immersive-reader-sdk'를 추가하여 CocoaPod를 Podfile에 추가합니다. Podfile은 picture-to-immersive-reader-swift를 대상의 이름으로 바꿔 다음과 같습니다.

    platform :ios, '9.0'
    
    target 'picture-to-immersive-reader-swift' do
    use_frameworks!
    # Pods for picture-to-immersive-reader-swift
    pod 'immersive-reader-sdk', :git => 'https://github.com/microsoft/immersive-reader-sdk.git'
    end
    
  4. 터미널의 Xcode 프로젝트 디렉터리에서 pod install 명령을 실행하여 몰입형 리더 SDK Pod를 설치합니다.

  5. SDK를 참조해야 하는 모든 파일에 import immersive_reader_sdk를 추가합니다.

  6. .xcodeproj 파일이 아니라 .xcworkspace 파일을 열어 프로젝트를 열어야 합니다.

Microsoft Entra 인증 토큰 획득

필수 구성 요소 섹션의 Microsoft Entra 인증 구성 단계에서 일부 값이 필요합니다. 해당 세션에서 저장한 텍스트 파일을 다시 참조합니다.

TenantId     => Azure subscription TenantId
ClientId     => Microsoft Entra ApplicationId
ClientSecret => Microsoft Entra Application Service Principal password
Subdomain    => Immersive Reader resource subdomain (resource 'Name' if the resource was created in the Azure portal, or 'CustomSubDomain' option if the resource was created with Azure CLI PowerShell. Check the Azure portal for the subdomain on the Endpoint in the resource Overview page, for example, 'https://[SUBDOMAIN].cognitiveservices.azure.com/')

ViewController.swift 파일이 포함된 기본 프로젝트 폴더에서 Constants.swift라는 Swift 클래스 파일을 만듭니다. 클래스를 다음 코드로 바꾸고, 해당하는 경우 값을 추가합니다. 이 파일은 컴퓨터에만 있는 로컬 파일로 보관하고, 공개되지 않아야 하는 비밀이 포함되어 있으므로 원본 제어에 커밋하지 않아야 합니다. 앱에서 비밀을 유지하지 않는 것이 좋습니다. 대신 백 엔드 서비스를 사용하여 비밀을 앱 외부와 디바이스 외부에 보관할 수 있는 토큰을 가져오는 것이 좋습니다. 권한 없는 사용자가 토큰을 획득하여 몰입형 리더 서비스 및 청구에 사용하지 못하도록 백 엔드 API 엔드포인트를 인증 형식(예: OAuth)으로 보호해야 합니다. 이 작업은 이 자습서의 범위를 벗어납니다.

스토리보드 없이 실행되도록 앱 설정

AppDelegate.swift를 열고 파일을 다음 코드로 바꿉니다.

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    var window: UIWindow?
    
    var navigationController: UINavigationController?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        
        window = UIWindow(frame: UIScreen.main.bounds)
        
        // Allow the app run without a storyboard
        if let window = window {
            let mainViewController = PictureLaunchViewController()
            navigationController = UINavigationController(rootViewController: mainViewController)
            window.rootViewController = navigationController
            window.makeKeyAndVisible()
        }
        return true
    }

    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }

}

사진을 촬영하고 업로드하는 기능 추가

ViewController.swift의 이름을 PictureLaunchViewController.swift로 바꾸고 파일을 다음 코드로 바꿉니다.

import UIKit
import immersive_reader_sdk

class PictureLaunchViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

    private var photoButton: UIButton!
    private var cameraButton: UIButton!
    private var titleText: UILabel!
    private var bodyText: UILabel!
    private var sampleContent: Content!
    private var sampleChunk: Chunk!
    private var sampleOptions: Options!
    private var imagePicker: UIImagePickerController!
    private var spinner: UIActivityIndicatorView!
    private var activityIndicatorBackground: UIView!
    private var textURL = "vision/v2.0/read/core/asyncBatchAnalyze";
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .white
        
        titleText = UILabel()
        titleText.text = "Picture to Immersive Reader with OCR"
        titleText.font = UIFont.boldSystemFont(ofSize: 32)
        titleText.textAlignment = .center
        titleText.lineBreakMode = .byWordWrapping
        titleText.numberOfLines = 0
        view.addSubview(titleText)
        
        bodyText = UILabel()
        bodyText.text = "Capture or upload a photo of handprinted text on a piece of paper, handwriting, typed text, text on a computer screen, writing on a white board and many more, and watch it be presented to you in the Immersive Reader!"
        bodyText.font = UIFont.systemFont(ofSize: 18)
        bodyText.lineBreakMode = .byWordWrapping
        bodyText.numberOfLines = 0
        let screenSize = self.view.frame.height
        if screenSize <= 667 {
            // Font size for smaller iPhones.
            bodyText.font = bodyText.font.withSize(16)

        } else if screenSize <= 812.0 {
            // Font size for medium iPhones.
            bodyText.font = bodyText.font.withSize(18)
            
        } else if screenSize <= 896  {
            // Font size for larger iPhones.
            bodyText.font = bodyText.font.withSize(20)
            
        } else {
            // Font size for iPads.
            bodyText.font = bodyText.font.withSize(26)
        }
        view.addSubview(bodyText)
        
        photoButton = UIButton()
        photoButton.backgroundColor = .darkGray
        photoButton.contentEdgeInsets = UIEdgeInsets(top: 10, left: 5, bottom: 10, right: 5)
        photoButton.layer.cornerRadius = 5
        photoButton.setTitleColor(.white, for: .normal)
        photoButton.setTitle("Choose Photo from Library", for: .normal)
        photoButton.titleLabel?.font = UIFont.systemFont(ofSize: 18, weight: .bold)
        photoButton.addTarget(self, action: #selector(selectPhotoButton(sender:)), for: .touchUpInside)
        view.addSubview(photoButton)
        
        cameraButton = UIButton()
        cameraButton.backgroundColor = .darkGray
        cameraButton.contentEdgeInsets = UIEdgeInsets(top: 10, left: 5, bottom: 10, right: 5)
        cameraButton.layer.cornerRadius = 5
        cameraButton.setTitleColor(.white, for: .normal)
        cameraButton.setTitle("Take Photo", for: .normal)
        cameraButton.titleLabel?.font = UIFont.systemFont(ofSize: 18, weight: .bold)
        cameraButton.addTarget(self, action: #selector(takePhotoButton(sender:)), for: .touchUpInside)
        view.addSubview(cameraButton)
        
        activityIndicatorBackground = UIView()
        activityIndicatorBackground.backgroundColor = UIColor.black
        activityIndicatorBackground.alpha = 0
        view.addSubview(activityIndicatorBackground)
        view.bringSubviewToFront(_: activityIndicatorBackground)
        
        spinner = UIActivityIndicatorView(style: .whiteLarge)
        view.addSubview(spinner)
        
        let layoutGuide = view.safeAreaLayoutGuide
        
        titleText.translatesAutoresizingMaskIntoConstraints = false
        titleText.topAnchor.constraint(equalTo: layoutGuide.topAnchor, constant: 25).isActive = true
        titleText.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 20).isActive = true
        titleText.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -20).isActive = true
        
        bodyText.translatesAutoresizingMaskIntoConstraints = false
        bodyText.topAnchor.constraint(equalTo: titleText.bottomAnchor, constant: 35).isActive = true
        bodyText.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 20).isActive = true
        bodyText.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -20).isActive = true

        cameraButton.translatesAutoresizingMaskIntoConstraints = false
        if screenSize > 896  {
            // Constraints for iPads.
            cameraButton.heightAnchor.constraint(equalToConstant: 150).isActive = true
            cameraButton.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 60).isActive = true
            cameraButton.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -60).isActive = true
            cameraButton.topAnchor.constraint(equalTo: bodyText.bottomAnchor, constant: 150).isActive = true
        } else {
            // Constraints for iPhones.
            cameraButton.heightAnchor.constraint(equalToConstant: 100).isActive = true
            cameraButton.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 30).isActive = true
            cameraButton.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -30).isActive = true
            cameraButton.topAnchor.constraint(equalTo: bodyText.bottomAnchor, constant: 100).isActive = true
        }
        cameraButton.bottomAnchor.constraint(equalTo: photoButton.topAnchor, constant: -40).isActive = true
        
        photoButton.translatesAutoresizingMaskIntoConstraints = false
        if screenSize > 896  {
            // Constraints for iPads.
            photoButton.heightAnchor.constraint(equalToConstant: 150).isActive = true
            photoButton.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 60).isActive = true
            photoButton.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -60).isActive = true
        } else {
            // Constraints for iPhones.
            photoButton.heightAnchor.constraint(equalToConstant: 100).isActive = true
            photoButton.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor, constant: 30).isActive = true
            photoButton.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor, constant: -30).isActive = true
        }
        
        spinner.translatesAutoresizingMaskIntoConstraints = false
        spinner.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        spinner.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        
        activityIndicatorBackground.translatesAutoresizingMaskIntoConstraints = false
        activityIndicatorBackground.topAnchor.constraint(equalTo: layoutGuide.topAnchor).isActive = true
        activityIndicatorBackground.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor).isActive = true
        activityIndicatorBackground.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor).isActive = true
        activityIndicatorBackground.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor).isActive = true
        
        // Create content and options.
        sampleChunk = Chunk(content: bodyText.text!, lang: nil, mimeType: nil)
        sampleContent = Content(title: titleText.text!, chunks: [sampleChunk])
        sampleOptions = Options(uiLang: nil, timeout: nil, uiZIndex: nil)
    }
    
    @IBAction func selectPhotoButton(sender: AnyObject) {
            // Launch the photo picker.
            imagePicker =  UIImagePickerController()
            imagePicker.delegate = self
            self.imagePicker.sourceType = .photoLibrary
            self.imagePicker.allowsEditing = true
            self.present(self.imagePicker, animated: true, completion: nil)
            self.photoButton.isEnabled = true
    }
    
    @IBAction func takePhotoButton(sender: AnyObject) {
        if !UIImagePickerController.isSourceTypeAvailable(.camera) {
            // If there is no camera on the device, disable the button
            self.cameraButton.backgroundColor = .gray
            self.cameraButton.isEnabled = true
            
        } else {
            // Launch the camera.
            imagePicker =  UIImagePickerController()
            imagePicker.delegate = self
            self.imagePicker.sourceType = .camera
            self.present(self.imagePicker, animated: true, completion: nil)
            self.cameraButton.isEnabled = true
        }
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        imagePicker.dismiss(animated: true, completion: nil)
        photoButton.isEnabled = false
        cameraButton.isEnabled = false
        self.spinner.startAnimating()
        activityIndicatorBackground.alpha = 0.6
        
        // Retrieve the image.
        let image = (info[.originalImage] as? UIImage)!
        
        // Retrieve the byte array from image.
        let imageByteArray = image.jpegData(compressionQuality: 1.0)
        
        // Call the getTextFromImage function passing in the image the user takes or chooses.
        getTextFromImage(subscriptionKey: Constants.computerVisionSubscriptionKey, getTextUrl: Constants.computerVisionEndPoint + textURL, pngImage: imageByteArray!, onSuccess: { cognitiveText in
            print("cognitive text is: \(cognitiveText)")
            DispatchQueue.main.async {
                self.photoButton.isEnabled = true
                self.cameraButton.isEnabled = true
            }
            
            // Create content and options with the text from the image.
            let sampleImageChunk = Chunk(content: cognitiveText, lang: nil, mimeType: nil)
            let sampleImageContent = Content(title: "Text from image", chunks: [sampleImageChunk])
            let sampleImageOptions = Options(uiLang: nil, timeout: nil, uiZIndex: nil)
            
            // Callback to get token for Immersive Reader.
            self.getToken(onSuccess: {cognitiveToken in
                
                DispatchQueue.main.async {
                    
                    launchImmersiveReader(navController: self.navigationController!, token: cognitiveToken, subdomain: Constants.subdomain, content: sampleImageContent, options: sampleImageOptions, onSuccess: {
                        self.spinner.stopAnimating()
                        self.activityIndicatorBackground.alpha = 0
                        self.photoButton.isEnabled = true
                        self.cameraButton.isEnabled = true
                        
                    }, onFailure: { error in
                        print("An error occurred launching the Immersive Reader: \(error)")
                        self.spinner.stopAnimating()
                        self.activityIndicatorBackground.alpha = 0
                        self.photoButton.isEnabled = true
                        self.cameraButton.isEnabled = true
                        
                    })
                }

            }, onFailure: { error in
                DispatchQueue.main.async {
                    self.photoButton.isEnabled = true
                    self.cameraButton.isEnabled = true
                    
                }
                print("An error occurred retrieving the token: \(error)")
            })
            
        }, onFailure: { error in
            DispatchQueue.main.async {
                self.photoButton.isEnabled = true
                self.cameraButton.isEnabled = true
            }
            
        })
    }
    
    /// Retrieves the token for the Immersive Reader using Microsoft Entra authentication
    ///
    /// - Parameters:
    ///     -onSuccess: A closure that gets called when the token is successfully received using Microsoft Entra authentication.
    ///     -theToken: The token for the Immersive Reader received using Microsoft Entra authentication.
    ///     -onFailure: A closure that gets called when the token fails to be obtained from the Microsoft Entra authentication.
    ///     -theError: The error that occurred when the token fails to be obtained from the Microsoft Entra authentication.
    func getToken(onSuccess: @escaping (_ theToken: String) -> Void, onFailure: @escaping ( _ theError: String) -> Void) {
        
        let tokenForm = "grant_type=client_credentials&resource=https://cognitiveservices.azure.com/&client_id=" + Constants.clientId + "&client_secret=" + Constants.clientSecret
        let tokenUrl = "https://login.windows.net/" + Constants.tenantId + "/oauth2/token"
        
        var responseTokenString: String = "0"
        
        let url = URL(string: tokenUrl)!
        var request = URLRequest(url: url)
        request.httpBody = tokenForm.data(using: .utf8)
        request.httpMethod = "POST"
        
        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data,
                let response = response as? HTTPURLResponse,
                // Check for networking errors.
                error == nil else {
                    print("error", error ?? "Unknown error")
                    onFailure("Error")
                    return
            }
            
            // Check for http errors.
            guard (200 ... 299) ~= response.statusCode else {
                print("statusCode should be 2xx, but is \(response.statusCode)")
                print("response = \(response)")
                onFailure(String(response.statusCode))
                return
            }
            
            let responseString = String(data: data, encoding: .utf8)
            print("responseString = \(String(describing: responseString!))")
            
            let jsonResponse = try? JSONSerialization.jsonObject(with: data, options: [])
            guard let jsonDictonary = jsonResponse as? [String: Any] else {
                onFailure("Error parsing JSON response.")
                return
            }
            guard let responseToken = jsonDictonary["access_token"] as? String else {
                onFailure("Error retrieving token from JSON response.")
                return
            }
            responseTokenString = responseToken
            onSuccess(responseTokenString)
        }
        
        task.resume()
    }
    
    /// Returns the text string after it has been extracted from an Image input.
    ///
    /// - Parameters:
    ///     -subscriptionKey: The Azure subscription key.
    ///     -pngImage: Image data in PNG format.
    /// - Returns: a string of text representing the
    func getTextFromImage(subscriptionKey: String, getTextUrl: String, pngImage: Data, onSuccess: @escaping (_ theToken: String) -> Void, onFailure: @escaping ( _ theError: String) -> Void) {
        
        let url = URL(string: getTextUrl)!
        var request = URLRequest(url: url)
        request.setValue(subscriptionKey, forHTTPHeaderField: "Ocp-Apim-Subscription-Key")
        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
        
        // Two REST API calls are required to extract text. The first call is to submit the image for processing, and the next call is to retrieve the text found in the image.
        
        // Set the body to the image in byte array format.
        request.httpBody = pngImage
        
        request.httpMethod = "POST"
        
        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data,
                let response = response as? HTTPURLResponse,
                // Check for networking errors.
                error == nil else {
                    print("error", error ?? "Unknown error")
                    onFailure("Error")
                    return
            }
            
            // Check for http errors.
            guard (200 ... 299) ~= response.statusCode else {
                print("statusCode should be 2xx, but is \(response.statusCode)")
                print("response = \(response)")
                onFailure(String(response.statusCode))
                return
            }
            
            let responseString = String(data: data, encoding: .utf8)
            print("responseString = \(String(describing: responseString!))")
            
            // Send the second call to the API. The first API call returns operationLocation which stores the URI for the second REST API call.
            let operationLocation = response.allHeaderFields["Operation-Location"] as? String
            
            if (operationLocation == nil) {
                print("Error retrieving operation location")
                return
            }
            
            // Wait 10 seconds for text recognition to be available as suggested by the Text API documentation.
            print("Text submitted. Waiting 10 seconds to retrieve the recognized text.")
            sleep(10)
            
            // HTTP GET request with the operationLocation url to retrieve the text.
            let getTextUrl = URL(string: operationLocation!)!
            var getTextRequest = URLRequest(url: getTextUrl)
            getTextRequest.setValue(subscriptionKey, forHTTPHeaderField: "Ocp-Apim-Subscription-Key")
            getTextRequest.httpMethod = "GET"
            
            // Send the GET request to retrieve the text.
            let taskGetText = URLSession.shared.dataTask(with: getTextRequest) { data, response, error in
                guard let data = data,
                    let response = response as? HTTPURLResponse,
                    // Check for networking errors.
                    error == nil else {
                        print("error", error ?? "Unknown error")
                        onFailure("Error")
                        return
                }
                
                // Check for http errors.
                guard (200 ... 299) ~= response.statusCode else {
                    print("statusCode should be 2xx, but is \(response.statusCode)")
                    print("response = \(response)")
                    onFailure(String(response.statusCode))
                    return
                }
                
                // Decode the JSON data into an object.
                let customDecoding = try! JSONDecoder().decode(TextApiResponse.self, from: data)
                
                // Loop through the lines to get all lines of text and concatenate them together.
                var textFromImage = ""
                for textLine in customDecoding.recognitionResults[0].lines {
                    textFromImage = textFromImage + textLine.text + " "
                }
                
                onSuccess(textFromImage)
            }
            taskGetText.resume()

        }
        
        task.resume()
    }
    
    // Structs used for decoding the Text API JSON response.
    struct TextApiResponse: Codable {
        let status: String
        let recognitionResults: [RecognitionResult]
    }

    struct RecognitionResult: Codable {
        let page: Int
        let clockwiseOrientation: Double
        let width, height: Int
        let unit: String
        let lines: [Line]
    }

    struct Line: Codable {
        let boundingBox: [Int]
        let text: String
        let words: [Word]
    }

    struct Word: Codable {
        let boundingBox: [Int]
        let text: String
        let confidence: String?
    }
    
}

앱 빌드 및 실행

시뮬레이터 또는 디바이스 대상을 선택하여 Xcode에서 보관 체계를 설정합니다.

보관 스트림의 스크린샷.

시뮬레이터 선택 대상의 스크린샷.

Xcode에서 Ctrl+R을 누르거나 재생 단추를 선택하여 프로젝트를 실행합니다. 지정된 시뮬레이터 또는 디바이스에서 앱이 시작됩니다.

앱에서 다음과 같이 표시됩니다.

읽을 텍스트가 있는 샘플 앱의 스크린샷.

사진 찍기 단추 또는 라이브러리에서 사진 선택 단추를 눌러 텍스트 사진을 찍거나 업로드합니다. 그런 다음, Immersive Reader가 실행되어 사진의 텍스트를 표시합니다.

Immersive Reader 앱의 스크린샷.

다음 단계