a11ySnapshot (#91)

Author: noahsmartin

DemoApp/DemoApp/TestViews/PreviewVariants.swift

@@ -64,11 +64,15 @@ extension NamedViewModifier {
   static var xxlTextSize: NamedViewModifier {
     .init(name: "XXL Text Size", value: { $0.dynamicTypeSize(.xxxLarge) })
   }
+
+  static var accessibility: NamedViewModifier {
+    .init(name: "Accessibility", value: { $0.emergeAccessibility(true) })
+  }
 }
 
 extension [NamedViewModifier] {
   /// The default named view modifiers in a ``PreviewVariants``.
   static var previewDefault: [NamedViewModifier] {
-    [.unmodified, .darkMode, .xxlTextSize]
+    [.unmodified, .darkMode, .xxlTextSize, .accessibility]
   }
 }

DemoApp/DemoApp/TestViews/RideShareButton.swift

@@ -45,5 +45,14 @@ struct RideShareButtonView_Previews: PreviewProvider {
       .preferredColorScheme(.dark)
       .previewLayout(.sizeThatFits)
       .padding()
+
+      RideShareButtonView(title: "Request Ride") {
+          print("Button tapped")
+      }
+      .previewLayout(.sizeThatFits)
+      .padding()
+      .previewDisplayName("Ride Share Button View - Light")
+      .emergeRenderingMode(.coreAnimation)
+      .emergeAccessibility(true)
     }
 }

Package.swift

@@ -34,14 +34,15 @@ let package = Package(
     ],
     dependencies: [
       .package(url: "https://github.com/swhitty/FlyingFox.git", exact: "0.12.2"),
+      .package(url: "https://github.com/EmergeTools/AccessibilitySnapshot.git", exact: "1.0.0"),
     ],
     targets: [
         // Targets are the basic building blocks of a package, defining a module or a test suite.
         // Targets can depend on other targets in this package and products from dependencies.
         // Target that provides the XCTest
         .target(name: "SnapshottingTests"),
         // Core functionality
-        .target(name: "SnapshotPreviewsCore", dependencies: ["PreviewsSupport"]),
+        .target(name: "SnapshotPreviewsCore", dependencies: ["PreviewsSupport", .product(name: "AccessibilitySnapshotCore", package: "AccessibilitySnapshot")]),
         .target(name: "SnapshotPreferences", dependencies: ["SnapshotPreviewsCore"]),
         // Inserted dylib
         .target(name: "Snapshotting", dependencies: ["SnapshottingSwift"]),

Sources/SnapshotPreferences/AccessibiltyPreference.swift

@@ -0,0 +1,25 @@
+//
+//  AccessibiltyPreference.swift
+//
+//
+//  Created by Noah Martin on 2/2/24.
+//
+
+import Foundation
+import SwiftUI
+
+struct AccessibilityPreferenceKey: PreferenceKey {
+  static func reduce(value: inout Bool?, nextValue: () -> Bool?) {
+    if value == nil {
+      value = nextValue()
+    }
+  }
+
+  static var defaultValue: Bool? = nil
+}
+
+extension View {
+  public func emergeAccessibility(_ enabled: Bool?) -> some View {
+    preference(key: AccessibilityPreferenceKey.self, value: enabled)
+  }
+}

Sources/SnapshotPreferences/EmergeModifierFinder.swift

@@ -23,11 +23,13 @@ class EmergeModifierState: NSObject {
     expansionPreference = nil
     renderingMode = nil
     precision = nil
+    accessibilityEnabled = nil
   }
 
   var expansionPreference: Bool?
   var renderingMode: EmergeRenderingMode.RawValue?
   var precision: Float?
+  var accessibilityEnabled: Bool?
 }
 
 @objc(EmergeModifierFinder)
@@ -44,5 +46,8 @@ class EmergeModifierFinder: NSObject {
       .onPreferenceChange(PrecisionPreferenceKey.self, perform: { value in
         EmergeModifierState.shared.precision = value
       })
+      .onPreferenceChange(AccessibilityPreferenceKey.self, perform: { value in
+        EmergeModifierState.shared.accessibilityEnabled = value
+      })
   }
 }

Sources/SnapshotPreviewsCore/ExpandingViewController.swift

@@ -53,7 +53,7 @@ public final class ExpandingViewController: UIHostingController<AnyView> {
 
   private var heightAnchor: NSLayoutConstraint?
 
-  var expansionSettled: ((EmergeRenderingMode?, Float?) -> Void)?
+  var expansionSettled: ((EmergeRenderingMode?, Float?, Bool?) -> Void)?
 
   init<Content: View>(rootView: Content, layout: PreviewLayout) {
     let newView = finder?(rootView)
@@ -81,7 +81,8 @@ public final class ExpandingViewController: UIHostingController<AnyView> {
     didCall = true
     let renderingMode = stateMirror?.descendant("renderingMode") as? EmergeRenderingMode.RawValue
     let emergeRenderingMode = renderingMode != nil ? EmergeRenderingMode(rawValue: renderingMode!) : nil
-    expansionSettled?(emergeRenderingMode, stateMirror?.descendant("precision") as? Float)
+    let accessibilityEnabled = stateMirror?.descendant("accessibilityEnabled") as? Bool
+    expansionSettled?(emergeRenderingMode, stateMirror?.descendant("precision") as? Float, accessibilityEnabled)
   }
 
   public override func viewDidLayoutSubviews() {

Sources/SnapshotPreviewsCore/View+Snapshot.swift

@@ -9,6 +9,7 @@
 import Foundation
 import SwiftUI
 import UIKit
+import AccessibilitySnapshotCore
 
 public enum RenderingError: Error {
   case failedRendering(CGSize)
@@ -35,16 +36,38 @@ extension View {
 
     let (windowRootVC, containerVC) = Self.setupRootVC(subVC: controller)
     window.rootViewController = windowRootVC
-    controller.expansionSettled = { [weak containerVC, weak controller] renderingMode, precision in
+    controller.expansionSettled = { [weak containerVC, weak controller] renderingMode, precision, accessibilityEnabled in
       guard let containerVC, let controller else { return }
 
       if async {
         DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
-          completion(Self.takeSnapshot(layout: layout, renderingMode: renderingMode, rootVC: containerVC, controller: controller), precision)
+          completion(Self.takeSnapshot(layout: layout, renderingMode: renderingMode, rootVC: containerVC, targetView: controller.view), precision)
         }
       } else {
         DispatchQueue.main.async {
-          completion(Self.takeSnapshot(layout: layout, renderingMode: renderingMode, rootVC: containerVC, controller: controller), precision)
+          if let accessibilityEnabled, accessibilityEnabled {
+            let containedView: UIView
+            switch layout {
+            case .device:
+              containedView = containerVC.view
+            default:
+              containedView = view
+            }
+            let a11yView = AccessibilitySnapshotView(
+              containedView: containedView,
+              viewRenderingMode: renderingMode?.a11yRenderingMode ?? .drawHierarchyInRect,
+              activationPointDisplayMode: .never,
+              showUserInputLabels: true)
+
+            a11yView.center = window.center
+            window.addSubview(a11yView)
+
+            try? a11yView.parseAccessibility(useMonochromeSnapshot: false)
+            a11yView.sizeToFit()
+            completion(Self.takeSnapshot(layout: .sizeThatFits, renderingMode: renderingMode, rootVC: containerVC, targetView: a11yView), precision)
+          } else {
+            completion(Self.takeSnapshot(layout: layout, renderingMode: renderingMode, rootVC: containerVC, targetView: view), precision)
+          }
         }
       }
     }
@@ -82,9 +105,9 @@ extension View {
     layout: PreviewLayout,
     renderingMode: EmergeRenderingMode?,
     rootVC: UIViewController,
-    controller: UIViewController) -> Result<UIImage, RenderingError>
+    targetView: UIView) -> Result<UIImage, RenderingError>
   {
-    let view = controller.view!
+    let view = targetView
     let drawCode: (CGContext) -> Void
 
     CATransaction.commit()
@@ -142,6 +165,16 @@ extension UIView {
   }
 }
 
+extension EmergeRenderingMode {
+  var a11yRenderingMode: AccessibilitySnapshotView.ViewRenderingMode {
+    switch self {
+    case .coreAnimation:
+      return .renderLayerInContext
+    case .uiView:
+      return .drawHierarchyInRect
+    }
+  }
+}
 
 extension CALayer {