Load PreviewModifier before rendering preview

.github/workflows/build.yml

@@ -35,13 +35,13 @@ jobs:
       - name: Build SnapshottingTests
         run: xcodebuild build -scheme SnapshottingTests -sdk appletvsimulator -destination 'generic/platform=tvOS Simulator'
   build-visionos:
-      runs-on: macos-14
+      runs-on: macos-15
 
       steps:
       - name: Checkout code
         uses: actions/checkout@v2
       - name: Xcode select
-        run: sudo xcode-select -s '/Applications/Xcode_15.4.app/Contents/Developer'
+        run: sudo xcode-select -s '/Applications/Xcode_16.0.app/Contents/Developer'
       - name: Build TestApp
         run: cd Examples && xcodebuild build -scheme DemoApp -sdk xrsimulator -destination 'generic/platform=visionOS Simulator' -project DemoApp/DemoApp.xcodeproj
       - name: Build Snapshotting
@@ -57,7 +57,7 @@ jobs:
       - name: Xcode select
         run: sudo xcode-select -s '/Applications/Xcode_15.4.app/Contents/Developer'
       - name: Build Test Watch App
-        run: cd Examples && xcodebuild build -scheme 'Demo Watch App' -sdk watchsimulator -destination 'platform=watchOS Simulator,name=Apple Watch Series 9 (41mm)' -project DemoApp/DemoApp.xcodeproj CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO
+        run: cd Examples && xcodebuild build -scheme 'Demo Watch App' -sdk watchsimulator -destination 'generic/platform=watchOS Simulator' -project DemoApp/DemoApp.xcodeproj CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO
       - name: Build Snapshotting
         run: xcodebuild build -scheme Snapshotting -sdk watchsimulator -destination 'generic/platform=watchOS Simulator'
       - name: Build SnapshottingTests

.github/workflows/release.yaml

@@ -16,15 +16,18 @@ jobs:
         run: sudo xcode-select -s '/Applications/Xcode_15.4.app/Contents/Developer'
       - name: Build xcframework
         run: sh build.sh
-      - name: Zip xcframework
+      - name: Zip SnapshottingTests xcframework
         run: zip -r SnapshottingTests.xcframework.zip SnapshottingTests.xcframework
+      - name: Zip PreviewGallery xcframework
+        run: zip -r PreviewGallery.xcframework.zip PreviewGallery.xcframework
       - name: Zip preivews support
         run: (cd PreviewsSupport && zip -r PreviewsSupport.xcframework.zip PreviewsSupport.xcframework)
       - name: Upload Artifact
         uses: softprops/action-gh-release@v1
         if: startsWith(github.ref, 'refs/tags/')
         with:
           files: |
+            PreviewGallery.xcframework.zip
             SnapshottingTests.xcframework.zip
             PreviewsSupport/PreviewsSupport.xcframework.zip
           body:

Package.swift

@@ -10,6 +10,7 @@ let package = Package(
         // Products define the executables and libraries a package produces, making them visible to other packages.
         .library(
           name: "PreviewGallery",
+          type: .static, // Replace this to build dynamic
           targets: ["PreviewGallery"]),
         // Test library to import in your XCTest target.
         // This is the only library that depends on XCTest.framework

README.md

@@ -1,7 +1,9 @@
 # 📸 SnapshotPreviews
 
-[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FEmergeTools%2FSnapshotPreviews-iOS%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/EmergeTools/SnapshotPreviews-iOS)
-[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FEmergeTools%2FSnapshotPreviews-iOS%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/EmergeTools/SnapshotPreviews-iOS)
+[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FEmergeTools%2FSnapshotPreviews%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/EmergeTools/SnapshotPreviews)
+[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FEmergeTools%2FSnapshotPreviews%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/EmergeTools/SnapshotPreviews)
+[![](https://img.shields.io/badge/dynamic/json?url=https%3A%2F%2Fwww.emergetools.com%2Fapi%2Fv2%2Fpublic_new_build%3FexampleId%3Dsnapshotpreviews-ios.PreviewGallery%26platform%3Dios%26badgeOption%3Dversion_and_max_install_size%26buildType%3Drelease&query=$.badgeMetadata&label=PreviewGallery&logo=apple)](https://www.emergetools.com/app/example/ios/snapshotpreviews-ios.PreviewGallery/release?utm_campaign=badge-data)
+[![](https://img.shields.io/badge/dynamic/json?url=https%3A%2F%2Fwww.emergetools.com%2Fapi%2Fv2%2Fpublic_new_build%3FexampleId%3Dsnapshotpreviews-ios.SnapshottingTests%26platform%3Dios%26badgeOption%3Dversion_and_max_install_size%26buildType%3Drelease&query=$.badgeMetadata&label=SnapshottingTests&logo=apple)](https://www.emergetools.com/app/example/ios/snapshotpreviews-ios.SnapshottingTests/release?utm_campaign=badge-data)
 
 An all-in-one snapshot testing solution built on Xcode previews. Automatic browsable gallery of previews, and no-code snapshot generation with XCTest. Supports SwiftUI and UIKit previews using `PreviewProvider` or `#Preview` and works on all Apple platforms (iOS/macOS/watchOS/tvOS/visionOS).
 
@@ -16,7 +18,7 @@ An all-in-one snapshot testing solution built on Xcode previews. Automatic brows
 `PreviewGallery` is an interactive UI built on top of snapshot extraction. It turns your Xcode previews into a gallery of components and features you can access from your application, for example in an internal settings screen. **Xcode is not required to view the previews.** You can use it to preview individual components (buttons/rows/icons/etc) or even entire interactive features.
 
 <p align="center">
-  <img src="https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews-iOS/master/images/image1.png" />
+  <img src="https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews/master/images/image1.png" />
 </p>
 
 The public API of PreviewGallery is a single SwiftUI `View` named `PreviewGallery`. Displaying this view gives you access to the full gallery. For example, you could add a button to open the gallery like this:
@@ -65,7 +67,7 @@ Note that there are no test functions; they are automatically added at runtime b
 > [!NOTE]
 > When you use Preview macros (`#Preview("Display Name")`) the name of the snapshot uses the file path and the name, for example: "MyModule/MyFile.swift:Display Name"
 
-![Screenshot of Xcode test output](https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews-iOS/master/images/testOutput.png)
+![Screenshot of Xcode test output](https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews/master/images/testOutput.png)
 
 The [EmergeTools snapshot testing service](https://docs.emergetools.com/docs/snapshot-testing) generates snapshots and diffs them in the cloud to control for sources of flakiness, store images outside of git, and optimize test performance. `SnapshotTest` is for locally debugging these snapshot tests. You can also use `PreviewTest` to get code coverage of all previews in your unit test without generating PNGs. This will validate that previews do not crash (such as a missing @EnvironmentObject) but runs faster because it does not render the views to images.
 
@@ -101,10 +103,10 @@ See the demo app for a full example.
 
 # Installation
 
-Add the package dependency to your Xcode project using the URL of this repository (https://github.com/EmergeTools/SnapshotPreviews-iOS).
+Add the package dependency to your Xcode project using the URL of this repository (https://github.com/EmergeTools/SnapshotPreviews).
 
 <p align="center">
-  <img src="https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews-iOS/master/images/image2.png" />
+  <img src="https://raw.githubusercontent.com/EmergeTools/SnapshotPreviews/master/images/image2.png" />
 </p>
 
 Link your app to `PreviewGallery` and (optionally) to `SnapshotPreferences` to customize the behavior of snapshot generation.
@@ -150,7 +152,7 @@ Check `ProcessInfo.isRunningPeviews` to disable behavior you don’t want in pre
 > [!TIP]
 > Using PreviewVariants greatly simplifies snapshot testing, by ensuring a consistent set of variants and that every view is provided a name.
 
-Using multiple variants of the same view can ensure test coverage of all the ways users interact with your UI. Most are provided by SwiftUI, eg: `.dynamicTypeSize(.xxxLarge)`. There is one built into the package: `.emergeAccessibility(true)`. This function adds a visualization of voice over elements to your snapshot. You can automatically add variants using the [`PreviewVariants` View](https://github.com/EmergeTools/SnapshotPreviews-iOS/blob/main/DemoApp/DemoApp/TestViews/PreviewVariants.swift) that is demonstrated in the example app. It adds RTL, landscape, accessibility, dark mode and large text variants. You can use it like this:
+Using multiple variants of the same view can ensure test coverage of all the ways users interact with your UI. Most are provided by SwiftUI, eg: `.dynamicTypeSize(.xxxLarge)`. There is one built into the package: `.emergeAccessibility(true)`. This function adds a visualization of voice over elements to your snapshot. You can automatically add variants using the [`PreviewVariants` View](https://github.com/EmergeTools/SnapshotPreviews/blob/main/Examples/DemoApp/DemoApp/TestViews/PreviewVariants.swift) that is demonstrated in the example app. It adds RTL, landscape, accessibility, dark mode and large text variants. You can use it like this:
 
 ```swift
 struct MyView_Previews: PreviewProvider {
@@ -172,7 +174,7 @@ struct MyView_Previews: PreviewProvider {
 
 # Star History
 
-[![Star History Chart](https://api.star-history.com/svg?repos=EmergeTools/SnapshotPreviews-iOS&type=Date)](https://star-history.com/#EmergeTools/SnapshotPreviews-iOS&Date)
+[![Star History Chart](https://api.star-history.com/svg?repos=EmergeTools/SnapshotPreviews&type=Date)](https://star-history.com/#EmergeTools/SnapshotPreviews&Date)
 
 # Related Reading
 - [How to use VariadicView, SwiftUI's Private View API](https://www.emergetools.com/blog/posts/how-to-use-variadic-view): VariadicView is a core part of how multiple images are rendered for one PreviewProvider.

Sources/SnapshotPreferences/AppStoreSnapshotPreference.swift

@@ -0,0 +1,48 @@
+//
+//  AppStoreSnapshotPreference.swift
+//
+//
+//  Created by Trevor Elkins on 09/30/24.
+//
+
+import Foundation
+import SwiftUI
+
+struct AppStoreSnapshotPreferenceKey: PreferenceKey {
+  static func reduce(value: inout Bool?, nextValue: () -> Bool?) {
+    if value == nil {
+      value = nextValue()
+    }
+  }
+
+  static var defaultValue: Bool? = nil
+}
+
+extension View {
+    /// Marks a snapshot for use with our App Store screenshot editing tool. This should ideally be used with a
+    /// full-size preview matching one of our supported devices.
+    ///
+    /// - Note: This method is only available on iOS. It is unavailable on macOS, watchOS, visionOS, and tvOS.
+    ///
+    /// - Parameter enabled: A Boolean value that determines whether the snapshot is for an App Store screenshot.
+    ///   If `nil`, the effect will default to `false`.
+    ///
+    /// - Returns: A view with the app store snapshot preference applied.
+    ///
+    /// # Example
+    /// ```swift
+    /// struct ContentView: View {
+    ///     var body: some View {
+    ///         Text("My App Store listing!")
+    ///             .emergeAppStoreSnapshot(true)
+    ///     }
+    /// }
+    /// ```
+    @available(macOS, unavailable)
+    @available(watchOS, unavailable)
+    @available(visionOS, unavailable)
+    @available(tvOS, unavailable)
+    public func emergeAppStoreSnapshot(_ enabled: Bool?) -> some View {
+        preference(key: AppStoreSnapshotPreferenceKey.self, value: enabled)
+    }
+}

Sources/SnapshotPreferences/EmergeModifierFinder.swift

@@ -30,6 +30,7 @@ class EmergeModifierState: NSObject {
   var renderingMode: EmergeRenderingMode.RawValue?
   var precision: Float?
   var accessibilityEnabled: Bool?
+  var appStoreSnapshot: Bool?
 }
 
 @objc(EmergeModifierFinder)
@@ -49,5 +50,8 @@ class EmergeModifierFinder: NSObject {
       .onPreferenceChange(AccessibilityPreferenceKey.self, perform: { value in
         EmergeModifierState.shared.accessibilityEnabled = value
       })
+      .onPreferenceChange(AppStoreSnapshotPreferenceKey.self, perform: { value in
+        EmergeModifierState.shared.appStoreSnapshot = value
+      })
   }
 }

Sources/SnapshotPreviewsCore/AppKitRenderingStrategy.swift

@@ -47,16 +47,17 @@ public class AppKitRenderingStrategy: RenderingStrategy {
     window.contentViewController = NSViewController()
     window.setContentSize(AppKitContainer.defaultSize)
     window.contentViewController = vc
-    vc.rendered = { [weak vc] mode, precision, accessibilityEnabled in
+    vc.rendered = { [weak vc] mode, precision, accessibilityEnabled, appStoreSnapshot in
       DispatchQueue.main.async {
         let image = vc?.view.snapshot()
         completion(
           SnapshotResult(
-            image: image != nil ? .success(image!) : .failure(SwiftUIRenderingError.renderingError),
+            image: image != nil ? .success(image!) : .failure(RenderingError.failedRendering(vc?.view.bounds.size ?? .zero)),
             precision: precision,
             accessibilityEnabled: accessibilityEnabled,
             accessibilityMarkers: nil,
-            colorScheme: _colorScheme))
+            colorScheme: _colorScheme,
+            appStoreSnapshot: appStoreSnapshot))
       }
     }
   }
@@ -70,7 +71,7 @@ final class AppKitContainer: NSHostingController<EmergeModifierView>, ScrollExpa
   var heightAnchor: NSLayoutConstraint?
   var previousHeight: CGFloat?
 
-  public var rendered: ((EmergeRenderingMode?, Float?, Bool?) -> Void)? {
+  public var rendered: ((EmergeRenderingMode?, Float?, Bool?, Bool?) -> Void)? {
     didSet { didCall = false }
   }
 
@@ -120,7 +121,7 @@ final class AppKitContainer: NSHostingController<EmergeModifierView>, ScrollExpa
     guard !didCall else { return }
 
     didCall = true
-    rendered?(rootView.emergeRenderingMode, rootView.precision, rootView.accessibilityEnabled)
+    rendered?(rootView.emergeRenderingMode, rootView.precision, rootView.accessibilityEnabled, rootView.appStoreSnapshot)
   }
 
   override func updateViewConstraints() {

Sources/SnapshotPreviewsCore/ConformanceLookup.swift

@@ -11,26 +11,26 @@ import MachO
 private func getTypeName(descriptor: UnsafePointer<TargetModuleContextDescriptor>) -> String? {
   let flags = descriptor.pointee.flags
   var parentName: String? = nil
+  if descriptor.pointee.parent != 0 {
+    let parent = UnsafeRawPointer(descriptor).advanced(by: MemoryLayout<TargetModuleContextDescriptor>.offset(of: \.parent)!).advanced(by: Int(descriptor.pointee.parent))
+    if abs(descriptor.pointee.parent) % 2 == 1 {
+      return nil
+    }
+    parentName = getTypeName(descriptor: parent.assumingMemoryBound(to: TargetModuleContextDescriptor.self))
+  }
   switch flags.kind {
   case .Module, .Enum, .Struct, .Class:
     let name = UnsafeRawPointer(descriptor)
       .advanced(by: MemoryLayout<TargetModuleContextDescriptor>.offset(of: \.name)!)
       .advanced(by: Int(descriptor.pointee.name))
       .assumingMemoryBound(to: CChar.self)
     let typeName = String(cString: name)
-    if descriptor.pointee.parent != 0 {
-      let parent = UnsafeRawPointer(descriptor).advanced(by: MemoryLayout<TargetModuleContextDescriptor>.offset(of: \.parent)!).advanced(by: Int(descriptor.pointee.parent))
-      if abs(descriptor.pointee.parent) % 2 == 1 {
-        return nil
-      }
-      parentName = getTypeName(descriptor: parent.assumingMemoryBound(to: TargetModuleContextDescriptor.self))
-    }
     if let parentName = parentName {
       return "\(parentName).\(typeName)"
     }
     return typeName
   default:
-    return nil
+    return parentName
   }
 }
 

Sources/SnapshotPreviewsCore/ExpandingViewController.swift

@@ -31,7 +31,7 @@ public final class ExpandingViewController: UIHostingController<EmergeModifierVi
   private var startTime: Date?
   private var timer: Timer?
 
-  public var expansionSettled: ((EmergeRenderingMode?, Float?, Bool?, Error?) -> Void)? {
+  public var expansionSettled: ((EmergeRenderingMode?, Float?, Bool?, Bool?, Error?) -> Void)? {
     didSet { didCall = false }
   }
 
@@ -78,7 +78,7 @@ public final class ExpandingViewController: UIHostingController<EmergeModifierVi
     guard !didCall else { return }
 
     didCall = true
-    expansionSettled?(rootView.emergeRenderingMode, rootView.precision, rootView.accessibilityEnabled, error)
+    expansionSettled?(rootView.emergeRenderingMode, rootView.precision, rootView.accessibilityEnabled, rootView.appStoreSnapshot, error)
     stopAndResetTimer()
   }
 

Sources/SnapshotPreviewsCore/ModifierFinder.swift

@@ -39,6 +39,10 @@ public struct EmergeModifierView: View {
     stateMirror?.descendant("accessibilityEnabled") as? Bool
   }
 
+  var appStoreSnapshot: Bool? {
+    stateMirror?.descendant("appStoreSnapshot") as? Bool
+  }
+
   var precision: Float? {
     stateMirror?.descendant("precision") as? Float
   }

Sources/SnapshotPreviewsCore/PreviewModifier/AnyPreviewModifier.swift

@@ -0,0 +1,31 @@
+//
+//  AnyPreviewModifier.swift
+//  SnapshotPreviews
+//
+//  Created by Itay Brenner on 26/9/24.
+//
+
+import SwiftUI
+
+@available(iOS 18.0, macOS 15.0, tvOS 18.0, watchOS 11.0, *)
+struct AnyPreviewModifier: PreviewModifier {
+
+  private let _body: (PreviewModifier.Content) -> AnyView
+
+  init<M: PreviewModifier>(_ modifier: M) {
+    let type = type(of: modifier)
+    let hash = String(describing: type)
+
+    _body = { content in
+      let cachedContext = PreviewModifierContextCache.contextCache[hash]
+      guard let typedContext = cachedContext as? M.Context else {
+        fatalError("Context type mismatch, expected: \(String(describing: M.Context.self)), got: \(String(describing: cachedContext.self))")
+      }
+      return AnyView(modifier.body(content: content, context: typedContext))
+    }
+  }
+
+  func body(content: PreviewModifier.Content, context: Void) -> AnyView {
+    return _body(content)
+  }
+}

Sources/SnapshotPreviewsCore/PreviewModifier/PreviewModifierContextCache.swift

@@ -0,0 +1,13 @@
+//
+//  PreviewModifierContextCache.swift
+//  SnapshotPreviews
+//
+//  Created by Itay Brenner on 26/9/24.
+//
+
+import SwiftUI
+
+@available(iOS 18.0, macOS 15.0, tvOS 18.0, watchOS 11.0, *)
+struct PreviewModifierContextCache {
+  static var contextCache: [String: Any] = [:]
+}

Sources/SnapshotPreviewsCore/PreviewModifier/View+PreviewModifier.swift

@@ -0,0 +1,21 @@
+//
+//  View+PreviewModifier.swift
+//  SnapshotPreviews
+//
+//  Created by Itay Brenner on 25/9/24.
+//
+
+import SwiftUI
+import PreviewsSupport
+
+extension View {
+  @available(iOS 18.0, macOS 15.0, tvOS 18.0, watchOS 11.0, *)
+  func applyPreviewModifiers(_ modifiers: [any PreviewModifier]) -> some View {
+    var currentView: AnyView = AnyView(self)
+    for modifier in modifiers {
+      let viewModifier = PreviewModifierSupport.toViewModifier(modifier: AnyPreviewModifier(modifier))
+      currentView = AnyView(currentView.modifier(viewModifier))
+    }
+    return currentView
+  }
+}

Sources/SnapshotPreviewsCore/RenderingStrategy.swift

@@ -41,26 +41,33 @@ public struct SnapshotResult {
     precision: Float?,
     accessibilityEnabled: Bool?,
     accessibilityMarkers: [AccessibilityMark]?,
-    colorScheme: ColorScheme?)
+    colorScheme: ColorScheme?,
+    appStoreSnapshot: Bool?)
   {
     self.image = image
     self.precision = precision
     self.accessibilityEnabled = accessibilityEnabled
     self.accessibilityMarkers = accessibilityMarkers
     self.colorScheme = colorScheme
+    self.appStoreSnapshot = appStoreSnapshot
   }
 
   public let image: Result<ImageType, Error>
   public let precision: Float?
   public let accessibilityEnabled: Bool?
   public let accessibilityMarkers: [AccessibilityMark]?
   public let colorScheme: ColorScheme?
+  public let appStoreSnapshot: Bool?
 }
 
 public protocol RenderingStrategy {
   @MainActor func render(
     preview: SnapshotPreviewsCore.Preview,
     completion: @escaping (SnapshotResult) -> Void)
+
+  @MainActor func preparePreview(
+    preview: SnapshotPreviewsCore.Preview
+  ) async
 }
 
 private let testHandler: NSObject.Type? = NSClassFromString("EMGTestHandler") as? NSObject.Type
@@ -69,5 +76,13 @@ extension RenderingStrategy {
   static func setup() {
     testHandler?.perform(NSSelectorFromString("setup"))
   }
+
+  @MainActor public func preparePreview(
+    preview: SnapshotPreviewsCore.Preview
+  ) async {
+    if #available(iOS 18.0, *) {
+      await preview.loadPreviewModifiers()
+    }
+  }
 }