[UI] Allow disabling image transitions

AsyncImageView/AsyncImageView.swift

@@ -38,6 +38,7 @@ open class AsyncImageView<
 	private let requestsObserver: Signal<Data?, Never>.Observer
 
 	private let imageCreationScheduler: ReactiveSwift.Scheduler
+	private let animatesImageChanges: Bool
 
 	private var disposable: Disposable?
 
@@ -46,10 +47,12 @@ open class AsyncImageView<
 		renderer: Renderer,
 		placeholderRenderer: PlaceholderRenderer? = nil,
 		uiScheduler: ReactiveSwift.Scheduler = UIScheduler(),
-		imageCreationScheduler: ReactiveSwift.Scheduler = QueueScheduler()
+		imageCreationScheduler: ReactiveSwift.Scheduler = QueueScheduler(),
+		animatesImageChanges: Bool = true
 	) {
 		(self.requestsSignal, self.requestsObserver) = Signal.pipe()
 		self.imageCreationScheduler = imageCreationScheduler
+		self.animatesImageChanges = animatesImageChanges
 
 		super.init(frame: initialFrame)
 
@@ -124,7 +127,7 @@ open class AsyncImageView<
 
 	private func updateImage(_ result: Renderer.RenderResult?) {
 		if let result = result {
-			if result.cacheHit {
+			if result.cacheHit || !self.animatesImageChanges {
 				self.image = result.image
 			} else {
 				UIView.transition(

AsyncImageViewTests/AsyncImageViewTests.swift

@@ -41,6 +41,19 @@ struct AsyncImageViewBehaviorTests {
 		await fixture.verifyRenderedImage()
 	}
 
+	@Test
+	func canDisableImageChangeAnimations() async {
+		let fixture = ImageViewFixture(
+			size: CGSize(width: 10, height: 10),
+			animatesImageChanges: false
+		)
+
+		fixture.view.data = .a
+
+		await fixture.verifyRenderedImage()
+		#expect(fixture.view.layer.animationKeys()?.isEmpty != false)
+	}
+
 	@Test
 	func updatingDataUpdatesImage() async {
 		let fixture = ImageViewFixture(size: CGSize(width: 10, height: 10))
@@ -237,13 +250,18 @@ private final class ImageViewFixture {
 	let view: ViewType
 	private let window = UIWindow()
 
-	init(size: CGSize = .zero, data: TestData? = nil) {
+	init(
+		size: CGSize = .zero,
+		data: TestData? = nil,
+		animatesImageChanges: Bool = true
+	) {
 		self.view = ViewType(
 			initialFrame: CGRect(origin: .zero, size: size),
 			renderer: self.renderer,
 			placeholderRenderer: nil,
 			uiScheduler: QueueScheduler(targeting: DispatchQueue.main),
-			imageCreationScheduler: ImmediateScheduler()
+			imageCreationScheduler: ImmediateScheduler(),
+			animatesImageChanges: animatesImageChanges
 		)
 		self.window.addSubview(self.view)
 		self.view.data = data