将视觉智能整合到 App 中的最佳做法

3:21 - Define the content you want to return as an App Entity

// Define the content you want to return as an App Entity
  import AppIntents
  
  struct AlbumEntity: AppEntity {
      var id: String
      @Property var name: String
      @Property var artistName: String
      var coverArtData: Data
      
      var displayRepresentation: DisplayRepresentation {
          DisplayRepresentation( 
              title: "\(name)",
              subtitle: "\(artistName)",
              image: .init(data: coverArtData)
          )   
      }   
      
      static let defaultQuery = AlbumEntityQuery()
      
      static var typeDisplayRepresentation: TypeDisplayRepresentation { "Album" }
  }   
  
  struct AlbumEntityQuery: EntityQuery {
      @Dependency var catalog: AlbumCatalog
      func entities(for identifiers: [String]) async throws -> [AlbumEntity] {
          catalog.albums(for: identifiers)
      }
  }

5:39 - Adopt IntentValueQuery to return results

// Adopt IntentValueQuery to return visual search results
  import AppIntents
  import VisualIntelligence
  
  struct SearchHandler: IntentValueQuery {
      @Dependency var catalog: AlbumCatalog
      @Dependency var concertFinder: ConcertFinder
      
      func values(for input: SemanticContentDescriptor) async throws -> [VisualSearchResult] {
          guard let pixelBuffer = input.pixelBuffer else {
              return []
          }   
          
          let albums = try await catalog.search(matching: pixelBuffer)
          
          return albums.map { VisualSearchResult.album($0) }
      }
  }

6:24 - Build a catalog of albums with precomputed feature prints

// Build a catalog of albums with precomputed feature prints
  import Vision
  
  @Observable
  class AlbumCatalog {
      static let shared = AlbumCatalog()
      
      struct CatalogEntry: Sendable {
          let album: AlbumEntity
          let featurePrint: FeaturePrintObservation
      }   
      
      private(set) var entries: [CatalogEntry] = []
      
      private func generateFeaturePrint(
          for image: CGImage
      ) async throws -> FeaturePrintObservation {
          let request = GenerateImageFeaturePrintRequest()
          let result = try await request.perform(on: image)
          return result
      }
  }

6:45 - Search the catalog for albums matching the captured image

// Search the catalog for albums matching the captured image
  func search(matching pixelBuffer: CVReadOnlyPixelBuffer, limit: Int = 10, maxDistance: Double = 1.0) async throws ->
  [AlbumEntity] {
      var cgImage: CGImage?
      _ = pixelBuffer.withUnsafeBuffer { VTCreateCGImageFromCVPixelBuffer($0, options: nil, imageOut: &cgImage) }
      guard let cgImage else { return [] }
      
      let queryPrint = try await generateFeaturePrint(for: cgImage)
      
      return try entries.compactMap { entry -> (album: AlbumEntity, distance: Double)? in
          let distance = try queryPrint.distance(to: entry.featurePrint)
          guard distance <= maxDistance else { return nil }
          return (entry.album, distance)
      }   
      .sorted { $0.distance < $1.distance }
      .prefix(limit)
      .map { $0.album }
  }

8:27 - Create an open intent to land users on the right screen

// Create an open intent to land users on the right screen
  import AppIntents
  
  struct OpenAlbumIntent: OpenIntent {
      static let title: LocalizedStringResource = "Open Album"
      
      @Parameter(title: "Album")
      var target: AlbumEntity
      
      @Dependency var appState: AppState
      
      func perform() async throws -> some IntentResult {
          await appState.openAlbum(id: target.id)
          return .result()
      }
  }

12:05 - Use UnionValue to return multiple visual search result types

// Use UnionValue to return multiple visual search result types
  @UnionValue
  enum VisualSearchResult {
      case album(AlbumEntity)
      case concert(ConcertEntity)
  }   
  
  struct OpenConcertIntent: OpenIntent {
      static let title: LocalizedStringResource = "Open Concert"
      
      @Parameter(title: "Concert")
      var target: ConcertEntity
      
      @Dependency var appState: AppState
      
      func perform() async throws -> some IntentResult {
          await appState.openConcert(id: target.id)
          return .result()
      }
  }

12:18 - Expand the IntentValueQuery to return the UnionValue

// Expand the IntentValueQuery to return the UnionValue
  struct SearchHandler: IntentValueQuery {
      @Dependency var catalog: AlbumCatalog
      @Dependency var concertFinder: ConcertFinder
      
      func values(for input: SemanticContentDescriptor) async throws -> [VisualSearchResult] {
          guard let pixelBuffer = input.pixelBuffer else {
              return []
          }   
          
          let albums = try await catalog.search(matching: pixelBuffer)
          
          let artists = albums.map { $0.artistName }
          
          let concerts = await concertFinder.findNearby(byArtists: artists)

          return albums.map { VisualSearchResult.album($0) }
              + concerts.map { VisualSearchResult.concert($0) }
      }
  }

13:13 - Provide a link to in-app search

// Provide a link to in-app search
  @AppIntent(schema: .visualIntelligence.semanticContentSearch)
  struct SemanticContentSearchIntent: AppIntent {
      static let title: LocalizedStringResource = "Search in app"
      static let openAppWhenRun: Bool = true
      
      var semanticContent: SemanticContentDescriptor
      @Dependency var catalog: AlbumCatalog
      @Dependency var concertFinder: ConcertFinder
      @Dependency var appState: AppState
      
      func perform() async throws -> some IntentResult {
          guard let pixelBuffer = semanticContent.pixelBuffer else { return .result() }
          let albums = try await catalog.search(matching: pixelBuffer)
          let artists = albums.map { $0.artistName }
          let concerts = await concertFinder.findNearby(byArtists: artists)
          await appState.openSearch(albums: albums, concerts: concerts)
          return .result()
      }   
  }

15:24 - Request calendar access and fetch upcoming concerts

// Request calendar access and fetch upcoming concerts
  import EventKit
  
  @Observable
  class UpcomingConcertManager {
      private let eventStore = EKEventStore()
      var upcomingConcerts: [EKEvent] = []
      var authorizationStatus: EKAuthorizationStatus = .notDetermined
      
      func requestAccessAndFetch() async throws {
          let granted = try await eventStore.requestFullAccessToEvents()
          guard granted else {
              authorizationStatus = .denied
              return
          }   
          authorizationStatus = .fullAccess
          await fetchUpcomingConcerts()

          // ...
      }
  }

15:42 - Filter for upcoming events that match known artists in our catalog

// Filter for upcoming events that match known artists in our catalog
  class UpcomingConcertManager {
      func fetchUpcomingConcerts() async {
          let predicate = eventStore.predicateForEvents(
              withStart: .now,
              end: .now.addingTimeInterval(90 * 24 * 60 * 60),
              calendars: nil
          )   
          
          let events = eventStore.events(matching: predicate)
          
          upcomingConcerts = events.filter { event in
              AlbumCatalog.shared.entries.contains { entry in
                  event.title?.localizedCaseInsensitiveContains(entry.album.artistName) == true
              }
          }
      }
  }

15:44 - Observe newly created events

// Observe newly created events
  @Observable
  class UpcomingConcertManager {
      // ...

      func requestAccessAndFetch() async throws {
          // ...

          for await _ in NotificationCenter.default
              .notifications(
                  named: .EKEventStoreChanged
              ) {
              await fetchUpcomingConcerts()
          }
      }
  }