PhotosPicker WWDC Sample

ContentView.swift

import PhotosUI
import CoreTransferable
import SwiftUI

struct ContentView: View {
  @ObservedObject var viewModel: FilterModel = .shared

  var body: some View {
    NavigationStack {
      Gallery()
        .navigationTitle("Birthday Filter")
        .toolbar {
          PhotosPicker(
            selection: $viewModel.imageSelection,
            matching: .images
          ) {
            Label("Pick a photo", systemImage: "plus.app")
          }
          Button {
            viewModel.applyFilter()
          } label: {
            Label("Apply Filter", systemImage: "camera.filters")
          }
        }
    }
  }
}

struct Gallery: View {
  @ObservedObject var viewModel: FilterModel = .shared

  var body: some View {
    VStack {
      switch viewModel.imageState {
      case .success(let image):
        image
          .resizable()
          .aspectRatio(contentMode: .fill)
          .draggable(image)
      case .loading:
        ProgressView()
      case .empty:
        Text("No Photo \(Image(systemName: "photo"))")
          .font(.title2)
          .fontWeight(.semibold)
        Text("Drag and drop a photo or press\n \(Image(systemName: "plus.app")) to choose a photo manually.")
          .foregroundColor(.secondary)
          .multilineTextAlignment(.center)
      case .failure:
        Image(systemName: "exclamationmark.triangle.fill")
          .font(.system(size: 40))
          .foregroundColor(.white)
      }
    }
    .padding()
  }
}

@MainActor
class FilterModel: ObservableObject {
  static let shared = FilterModel()

  enum ImageState {
    case empty, loading(Progress), success(Image), failure(Error)
  }

  @Published private(set) var processedImage: Image?
  @Published var imageState: ImageState = .empty
  @Published var imageSelection: PhotosPickerItem? = nil {
    didSet {
      if let imageSelection = imageSelection {
        let progress = loadTransferable(from: imageSelection)
        imageState = .loading(progress)
      } else {
        imageState = .empty
      }
    }
  }

  func applyFilter() { /* Apply your filter */ }

  private func loadTransferable(from imageSelection: PhotosPickerItem) -> Progress {
    return imageSelection.loadTransferable(type: Image.self) { result in
      DispatchQueue.main.async {
        guard imageSelection == self.imageSelection else { return }
        switch result {
        case .success(let image?):
          self.imageState = .success(image)
        case .success(nil):
          self.imageState = .empty
        case .failure(let error):
          self.imageState = .failure(error)
        }
      }
    }
  }
}