photokit

name photokit description Implement, review, or improve photo picking, camera capture, and media handling in iOS apps using PhotoKit and AVFoundation. Use when working with PhotosPicker, PHPickerViewController, camera capture sessions (AVCaptureSession), photo library access, image loading and display, video recording, or media permissions. Also use when selecting photos from the library, taking pictures, recording video, processing images, or handling photo/camera privacy permissions in Swift apps. PhotoKit Modern patterns for photo picking, camera capture, image loading, and media permissions targeting iOS 26+ with Swift 6.3. Patterns are backward-compatible to iOS 16 unless noted. See references/photokit-patterns.md for complete picker recipes and references/camera-capture.md for AVCaptureSession patterns. Contents PhotosPicker (SwiftUI, iOS 16+) Privacy and Permissions Camera Capture Basics Image Loading and Display Common Mistakes Review Checklist References PhotosPicker (SwiftUI, iOS 16+) PhotosPicker is the native SwiftUI replacement for UIImagePickerController . It runs out-of-process, requires no photo library permission for browsing, and supports single or multi-selection with media type filtering. Single Selection import SwiftUI import PhotosUI struct SinglePhotoPicker : View { @State private var selectedItem: PhotosPickerItem ? @State private var selectedImage: Image ? var body: some View { VStack { if let selectedImage { selectedImage .resizable() .scaledToFit() .frame(maxHeight: 300 ) } PhotosPicker ( "Select Photo" , selection: $selectedItem , matching: .images) } .onChange(of: selectedItem) { _ , newItem in Task { if let data = try? await newItem ? .loadTransferable(type: Data . self ), let uiImage = UIImage (data: data) { selectedImage = Image (uiImage: uiImage) } } } } } Multi-Selection struct MultiPhotoPicker : View { @State private var selectedItems: [ PhotosPickerItem ] = [] @State private var selectedImages: [ Image ] = [] var body: some View { VStack { ScrollView (.horizontal) { HStack { ForEach (selectedImages.indices, id: \. self ) { index in selectedImages[index] .resizable() .scaledToFill() .frame(width: 100 , height: 100 ) .clipShape(.rect(cornerRadius: 8 )) } } } PhotosPicker ( "Select Photos" , selection: $selectedItems , maxSelectionCount: 5 , matching: .images ) } .onChange(of: selectedItems) { _ , newItems in Task { selectedImages = [] for item in newItems { if let data = try? await item.loadTransferable(type: Data . self ), let uiImage = UIImage (data: data) { selectedImages.append( Image (uiImage: uiImage)) } } } } } } Media Type Filtering Filter with PHPickerFilter composites to restrict selectable media: // Images only PhotosPicker (selection: $items , matching: .images) // Videos only PhotosPicker (selection: $items , matching: .videos) // Live Photos only PhotosPicker (selection: $items , matching: .livePhotos) // Screenshots only PhotosPicker (selection: $items , matching: .screenshots) // Images and videos combined PhotosPicker (selection: $items , matching: .any(of: [.images, .videos])) // Images excluding screenshots PhotosPicker (selection: $items , matching: .all(of: [.images, .not(.screenshots)])) Loading Selected Items with Transferable PhotosPickerItem loads content asynchronously via loadTransferable(type:) . Define a Transferable type for automatic decoding: struct PickedImage : Transferable { let data: Data let image: Image static var transferRepresentation: some TransferRepresentation { DataRepresentation (importedContentType: .image) { data in guard let uiImage = UIImage (data: data) else { throw TransferError .importFailed } return PickedImage (data: data, image: Image (uiImage: uiImage)) } } } enum TransferError : Error { case importFailed } // Usage if let picked = try? await item.loadTransferable(type: PickedImage . self ) { selectedImage = picked.image } Always load in a Task to avoid blocking the main thread. Handle nil returns and thrown errors -- the user may select a format that cannot be decoded. Privacy and Permissions Photo Library Access Levels iOS provides two access levels for the photo library. The system automatically presents the limited-library picker when an app requests .readWrite access -- users choose which photos to share. Access Level Description Info.plist Key Add-only Write photos to the library without reading NSPhotoLibraryAddUsageDescription Read-write Full or limited read access plus write NSPhotoLibraryUsageDescription PhotosPicker requires no permission to browse -- it runs out-of-process and only grants access to selected items. Request explicit permission only when you need to read the full library (e.g., a custom gallery) or save photos. Checking and Requesting Photo Library Permission import Photos func requestPhotoLibraryAccess () async -> PHAuthorizationStatus { let status = PHPhotoLibrary .authorizationStatus(for: .readWrite) switch status { case .notDetermined: return await PHPhotoLibrary .requestAuthorization(for: .readWrite) case .authorized, .limited: return status case .denied, .restricted: return status @unknown default : return status } } Camera Permission Add NSCameraUsageDescription to Info.plist. Check and request access before configuring a capture session: import AVFoundation func requestCameraAccess () async -> Bool { let status = AVCaptureDevice .authorizationStatus(for: .video) switch status { case .notDetermined: return await AVCaptureDevice .requestAccess(for: .video) case .authorized: return true case .denied, .restricted: return false @unknown default : return false } } Handling Denied Permissions When the user denies access, guide them to Settings. Never repeatedly prompt or hide functionality silently. struct PermissionDeniedView : View { let message: String @Environment (\.openURL) private var openURL var body: some View { ContentUnavailableView { Label ( "Access Denied" , systemImage: "lock.shield" ) } description: { Text (message) } actions: { Button ( "Open Settings" ) { if let url = URL (string: UIApplication .openSettingsURLString) { openURL(url) } } } } } Required Info.plist Keys Key When Required NSPhotoLibraryUsageDescription Reading photos from the library NSPhotoLibraryAddUsageDescription Saving photos/videos to the library NSCameraUsageDescription Accessing the camera NSMicrophoneUsageDescription Recording audio (video with sound) Omitting a required key causes a runtime crash when the permission dialog would appear. Camera Capture Basics Own each capture session in a dedicated controller and serialize configuration, startRunning() , and stopRunning() on the same non-main executor. Never mix main-actor configuration with detached start/stop tasks: beginConfiguration() / commitConfiguration() and session state changes must not race. The representable view only displays the preview. Minimal Camera Manager Load Camera Capture for the serialized-controller pattern, photo/video delegates, focus, torch, orientation, and scanning. The critical lifecycle is: Request access outside the session configuration transaction. On the capture executor, call beginConfiguration() and immediately install defer { commitConfiguration() } so every early exit balances the transaction. Add inputs and outputs only after canAddInput / canAddOutput checks. Start or stop on that same executor, then publish UI state on the main actor only after the synchronous call returns. On failure, stop, restore a fresh session fixture, fix the configuration, and rerun authorization, background/foreground, interruption, and capture checks. Camera Preview in SwiftUI Wrap AVCaptureVideoPreviewLayer in a UIViewRepresentable . Override layerClass for automatic resizing: import SwiftUI import AVFoundation struct CameraPreview : UIViewRepresentable { let session: AVCaptureSession func makeUIView ( context : Context ) -> PreviewView { let view = PreviewView () view.previewLayer.session = session view.previewLayer.videoGravity = .resizeAspectFill return view } func updateUIView ( _ uiView : PreviewView , context : Context ) { if uiView.previewLayer.session !== session { uiView.previewLayer.session = session } } } final class PreviewView : UIView { override class var layerClass: AnyClass { AVCaptureVideoPreviewLayer . self } var previewLayer: AVCaptureVideoPreviewLayer { layer as! AVCaptureVideoPreviewLayer } } Using the Camera in a View struct CameraScreen : View { @State private var cameraManager = CameraManager () var body: some View { ZStack (alignment: .bottom) { CameraPreview (session: cameraManager.session) .ignoresSafeArea() Button { // Capture photo -- see references/camera-capture.md } label: { Circle () .fill(.white) .frame(width: 72 , height: 72 ) .overlay( Circle ().stroke(.gray, lineWidth: 3 )) } .padding(.bottom) } .task { await cameraManager.configure() cameraManager.start() } .onDisappear { cameraManager.stop() } } } Always call stop() in onDisappear . A running capture session holds the camera exclusively and drains battery. Image Loading and Display AsyncImage for Remote Images AsyncImage (url: imageURL) { phase in switch phase { case .empty: ProgressView () case .success( let image): image .resizable() .scaledToFill() case .failure: Image (systemName: "photo" ) .foregroundStyle(.secondary) @unknown default : EmptyView () } } .frame(width: 200 , height: 200 ) .clipShape(.rect(cornerRadius: 12 )) AsyncImage does not cache images across view redraws. For production apps with many images, use a dedicated image loading library or URLCache -based caching. Downsampling Large Images Load full-resolution photos from the library into a display-sized CGImage to avoid memory spikes. A 48MP photo can consume over 200 MB uncompressed. import ImageIO import UIKit func downsample ( data : Data , to pointSize : CGSize , scale : CGFloat = UITraitCollection .current.displayScale) -> UIImage ? { let maxDimensionInPixels = max (pointSize.width, pointSize.height) * scale let options: [ CFString : Any ] = [ kCGImageSourceCreateThumbnailFromImageAlways: true , kCGImageSourceShouldCacheImmediately: true , kCGImageSourceCreateThumbnailWithTransform: true , kCGImageSourceThumbnailMaxPixelSize: maxDimensionInPixels ] guard let source = CGImageSourceCreateWithData (data as CFData , nil ), let cgImage = CGImageSourceCreateThumbnailAtIndex (source, 0 , options as CFDictionary ) else { return nil } return UIImage (cgImage: cgImage) } Use this whenever displaying user-selected photos in lists, grids, or thumbnails. Pass the raw Data from PhotosPickerItem directly to the downsampler before creating a UIImage . Image Rendering Modes // Original: display the image as-is with its original colors Image ( "photo" ) .renderingMode(.original) // Template: treat the image as a mask, colored by foregroundStyle Image (systemName: "heart.fill" ) .renderingMode(.template) .foregroundStyle(.red) Use .original for photos and artwork. Use .template for icons that should adopt the current tint color. Common Mistakes DON'T: Use UIImagePickerController for photo picking. DO: Use PhotosPicker (SwiftUI) or PHPickerViewController (UIKit). Why: UIImagePickerController is legacy API with limited functionality. PhotosPicker runs out-of-process, supports multi-selection, and requires no library permission for browsing. DON'T: Request full photo library access when you only need the user to pick photos. DO: Use PhotosPicker which requires no permission, or request .readWrite and let the system handle limited access. Why: Full access is unnecessary for most pick-and-use workflows. The system's limited-library picker respects user privacy and still grants access to selected items. DON'T: Load full-resolution images into memory for thumbnails. DO: Use CGImageSource with kCGImageSourceThumbnailMaxPixelSize to downsample. A 48MP image is over 200 MB uncompressed. DON'T: Block the main thread loading PhotosPickerItem data. DO: Use async loadTransferable(type:) in a Task . DON'T: Forget to stop AVCaptureSession when the view disappears. DO: Call session.stopRunning() in onDisappear or dismantleUIView . DON'T: Assume camera access is granted without checking. DO: Check AVCaptureDevice.authorizationStatus(for: .video) and handle .denied / .restricted . DON'T: Call session.startRunning() on the main thread. DO: Run it on the same dedicated serial executor that owns configuration and stop operations. Why: startRunning() is a synchronous blocking call that can take hundreds of milliseconds while the hardware initializes. DON'T: Create AVCaptureSession inside a UIViewRepresentable . DO: Own the session in a separate @Observable model. Review Checklist PhotosPicker used instead of deprecated UIImagePickerController Privacy descriptions in Info.plist for camera/photo library Loading states handled for async image/video loading Large images downsampled with CGImageSource before display Camera session started on background thread; stopped in onDisappear Permission denial handled with Settings deep link AVCaptureSession owned by model, not created inside UIViewRepresentable Media asset types and picker results are Sendable across concurrency boundaries References references/photokit-patterns.md — Picker patterns, media loading, HEIC handling references/camera-capture.md — AVCaptureSession, photo/video capture, QR scanning references/image-loading-caching.md — AsyncImage, caching, downsampling references/av-playback.md — AVPlayer, streaming, audio