Add TextProvider support to Core Animation rendering engine (airbnb…

…#1723)

Co-authored-by: Cal Stephens <[email protected]>

Lottie.xcodeproj/project.pbxproj

@@ -554,6 +554,7 @@
 		2EAF5B0427A0798700E00531 /* AnimationFontProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2EAF59F227A0798700E00531 /* AnimationFontProvider.swift */; };
 		2EAF5B0527A0798700E00531 /* AnimationFontProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2EAF59F227A0798700E00531 /* AnimationFontProvider.swift */; };
 		2EAF5B0627A0798700E00531 /* AnimationFontProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2EAF59F227A0798700E00531 /* AnimationFontProvider.swift */; };
+		36E57EAC28AF7ADF00B7EFDA /* HardcodedTextProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36E57EAB28AF7ADF00B7EFDA /* HardcodedTextProvider.swift */; };
 		6D0E635F28246BD0007C5DB6 /* Difference in Frameworks */ = {isa = PBXBuildFile; productRef = 6D0E635E28246BD0007C5DB6 /* Difference */; };
 		6D99D6432823790700E5205B /* LegacyGradientFillRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6D99D6422823790700E5205B /* LegacyGradientFillRenderer.swift */; };
 		6D99D6442823790700E5205B /* LegacyGradientFillRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6D99D6422823790700E5205B /* LegacyGradientFillRenderer.swift */; };
@@ -783,6 +784,7 @@
 		2EAF59EF27A0798700E00531 /* GradientValueProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GradientValueProvider.swift; sourceTree = "<group>"; };
 		2EAF59F027A0798700E00531 /* PointValueProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PointValueProvider.swift; sourceTree = "<group>"; };
 		2EAF59F227A0798700E00531 /* AnimationFontProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AnimationFontProvider.swift; sourceTree = "<group>"; };
+		36E57EAB28AF7ADF00B7EFDA /* HardcodedTextProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HardcodedTextProvider.swift; sourceTree = "<group>"; };
 		6D99D6422823790700E5205B /* LegacyGradientFillRenderer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LegacyGradientFillRenderer.swift; sourceTree = "<group>"; };
 		6DB3BDB528243FA5002A276D /* ValueProvidersTests.swift */ = {isa = PBXFileReference; indentWidth = 2; lastKnownFileType = sourcecode.swift; path = ValueProvidersTests.swift; sourceTree = "<group>"; tabWidth = 2; };
 		6DB3BDB7282454A6002A276D /* DictionaryInitializable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DictionaryInitializable.swift; sourceTree = "<group>"; };
@@ -876,6 +878,7 @@
 				2E8040BF27A07343006E74CB /* Snapshotting+presentationLayer.swift */,
 				2EAF59A627A076BC00E00531 /* Bundle+Module.swift */,
 				2E09FA0527B6CEB600BA84E5 /* HardcodedFontProvider.swift */,
+				36E57EAB28AF7ADF00B7EFDA /* HardcodedTextProvider.swift */,
 			);
 			path = Utils;
 			sourceTree = "<group>";
@@ -1876,6 +1879,7 @@
 				6DEF696E2824A76C007D640F /* BundleTests.swift in Sources */,
 				2EAF59A727A076BC00E00531 /* Bundle+Module.swift in Sources */,
 				2E8044AE27A07347006E74CB /* Snapshotting+presentationLayer.swift in Sources */,
+				36E57EAC28AF7ADF00B7EFDA /* HardcodedTextProvider.swift in Sources */,
 				2E72128527BB32DB0027BC56 /* PerformanceTests.swift in Sources */,
 				6DB3BDC328245AA2002A276D /* ParsingTests.swift in Sources */,
 				6DB3BDB628243FA5002A276D /* ValueProvidersTests.swift in Sources */,

Sources/Private/CoreAnimation/CoreAnimationLayer.swift

@@ -17,13 +17,15 @@ final class CoreAnimationLayer: BaseAnimationLayer {
   init(
     animation: Animation,
     imageProvider: AnimationImageProvider,
+    textProvider: AnimationTextProvider,
     fontProvider: AnimationFontProvider,
     compatibilityTrackerMode: CompatibilityTracker.Mode,
     logger: LottieLogger)
     throws
   {
     self.animation = animation
     self.imageProvider = imageProvider
+    self.textProvider = textProvider
     self.fontProvider = fontProvider
     self.logger = logger
     compatibilityTracker = CompatibilityTracker(mode: compatibilityTrackerMode, logger: logger)
@@ -44,6 +46,7 @@ final class CoreAnimationLayer: BaseAnimationLayer {
     animation = typedLayer.animation
     currentAnimationConfiguration = typedLayer.currentAnimationConfiguration
     imageProvider = typedLayer.imageProvider
+    textProvider = typedLayer.textProvider
     fontProvider = typedLayer.fontProvider
     didSetUpAnimation = typedLayer.didSetUpAnimation
     compatibilityTracker = typedLayer.compatibilityTracker
@@ -92,6 +95,16 @@ final class CoreAnimationLayer: BaseAnimationLayer {
     didSet { reloadImages() }
   }
 
+  /// The `AnimationTextProvider` that `TextLayer`'s use to retrieve texts,
+  /// that they should use to render their text context
+  var textProvider: AnimationTextProvider {
+    didSet {
+      // We need to rebuild the current animation after updating the text provider,
+      // since this is used in `TextLayer.setupAnimations(context:)`
+      rebuildCurrentAnimation()
+    }
+  }
+
   /// The `FontProvider` that `TextLayer`s use to retrieve the `CTFont`
   /// that they should use to render their text content
   var fontProvider: AnimationFontProvider {
@@ -203,6 +216,7 @@ final class CoreAnimationLayer: BaseAnimationLayer {
     LayerContext(
       animation: animation,
       imageProvider: imageProvider,
+      textProvider: textProvider,
       fontProvider: fontProvider,
       compatibilityTracker: compatibilityTracker,
       layerName: "root layer")
@@ -234,6 +248,7 @@ final class CoreAnimationLayer: BaseAnimationLayer {
       compatibilityTracker: compatibilityTracker,
       logger: logger,
       currentKeypath: AnimationKeypath(keys: []),
+      textProvider: textProvider,
       logHierarchyKeypaths: configuration.logHierarchyKeypaths)
 
     // Perform a layout pass if necessary so all of the sublayers
@@ -383,15 +398,6 @@ extension CoreAnimationLayer: RootAnimationLayer {
     (sublayers ?? []).filter { $0 is AnimationLayer }
   }
 
-  var textProvider: AnimationTextProvider {
-    get { DictionaryTextProvider([:]) }
-    set {
-      logger.assertionFailure("""
-        The Core Animation rendering engine currently doesn't support `textProvider`s")
-        """)
-    }
-  }
-
   func reloadImages() {
     // When the image provider changes, we have to update all `ImageLayer`s
     // so they can query the most up-to-date image from the new image provider.

Sources/Private/CoreAnimation/Layers/AnimationLayer.swift

@@ -41,6 +41,9 @@ struct LayerAnimationContext {
   /// The AnimationKeypath represented by the current layer
   var currentKeypath: AnimationKeypath
 
+  /// The `AnimationTextProvider`
+  var textProvider: AnimationTextProvider
+
   /// Whether or not to log `AnimationKeypath`s for all of the animation's layers
   ///  - Used for `CoreAnimationLayer.logHierarchyKeypaths()`
   var logHierarchyKeypaths: Bool

Sources/Private/CoreAnimation/Layers/LayerModel+makeAnimationLayer.swift

@@ -9,6 +9,7 @@ import QuartzCore
 struct LayerContext {
   let animation: Animation
   let imageProvider: AnimationImageProvider
+  let textProvider: AnimationTextProvider
   let fontProvider: AnimationFontProvider
   let compatibilityTracker: CompatibilityTracker
   var layerName: String

Sources/Private/CoreAnimation/Layers/TextLayer.swift

@@ -36,6 +36,21 @@ final class TextLayer: BaseCompositionLayer {
 
   // MARK: Internal
 
+  override func setupAnimations(context: LayerAnimationContext) throws {
+    try super.setupAnimations(context: context)
+    let textAnimationContext = context.addingKeypathComponent(textLayerModel.name)
+
+    let sourceText = try textLayerModel.text.exactlyOneKeyframe(
+      context: textAnimationContext,
+      description: "text layer text")
+
+    renderLayer.text = context.textProvider.textFor(
+      keypathName: textAnimationContext.currentKeypath.fullPath,
+      sourceText: sourceText.text)
+
+    renderLayer.sizeToFit()
+  }
+
   func configureRenderLayer(with context: LayerContext) throws {
     // We can't use `CATextLayer`, because it doesn't support enough features we use.
     // Instead, we use the same `CoreTextRenderLayer` (with a custom `draw` implementation)
@@ -54,7 +69,6 @@ final class TextLayer: BaseCompositionLayer {
         """)
     }
 
-    renderLayer.text = text.text
     renderLayer.font = context.fontProvider.fontFor(family: text.fontFamily, size: CGFloat(text.fontSize))
 
     renderLayer.alignment = text.justification.textAlignment

Sources/Public/Animation/AnimationView.swift

@@ -996,6 +996,7 @@ final public class AnimationView: AnimationViewBase {
       let coreAnimationLayer = try CoreAnimationLayer(
         animation: animation,
         imageProvider: imageProvider.cachedImageProvider,
+        textProvider: textProvider,
         fontProvider: fontProvider,
         compatibilityTrackerMode: .track,
         logger: logger)
@@ -1030,6 +1031,7 @@ final public class AnimationView: AnimationViewBase {
       let coreAnimationLayer = try CoreAnimationLayer(
         animation: animation,
         imageProvider: imageProvider.cachedImageProvider,
+        textProvider: textProvider,
         fontProvider: fontProvider,
         compatibilityTrackerMode: .abort,
         logger: logger)

Tests/AutomaticEngineTests.swift

@@ -19,6 +19,7 @@ final class AutomaticEngineTests: XCTestCase {
       let animationLayer = try XCTUnwrap(CoreAnimationLayer(
         animation: animation,
         imageProvider: BundleImageProvider(bundle: Bundle.main, searchPath: nil),
+        textProvider: DefaultTextProvider(),
         fontProvider: DefaultFontProvider(),
         compatibilityTrackerMode: .track,
         logger: .shared))

Tests/SnapshotConfiguration.swift

@@ -22,6 +22,9 @@ struct SnapshotConfiguration {
   /// A custom `AnimationImageProvider` to use when rendering this animation
   var customImageProvider: AnimationImageProvider?
 
+  /// A custom `AnimationTextProvider` to use when rendering this animation
+  var customTextProvider: AnimationTextProvider?
+
   /// A custom `AnimationFontProvider` to use when rendering this animation
   var customFontProvider: AnimationFontProvider?
 
@@ -70,6 +73,9 @@ extension SnapshotConfiguration {
     // Test cases for `AnimatedImageProvider`
     "Nonanimating/_dog": .customImageProvider(HardcodedImageProvider(imageName: "Samples/Images/dog.png")),
 
+    // Test cases for `AnimatedTextProvider`
+    "Issues/issue_1722": .customTextProvider(HardcodedTextProvider(text: "Bounce-bounce")),
+
     // Test cases for `AnimationFontProvider`
     "Nonanimating/Text_Glyph": .customFontProvider(HardcodedFontProvider(font: UIFont(name: "Chalkduster", size: 36)!)),
 
@@ -128,6 +134,15 @@ extension SnapshotConfiguration {
     return configuration
   }
 
+  static func customTextProvider(
+    _ customTextProvider: AnimationTextProvider)
+    -> SnapshotConfiguration
+  {
+    var configuration = SnapshotConfiguration.default
+    configuration.customTextProvider = customTextProvider
+    return configuration
+  }
+
   /// A `SnapshotConfiguration` value using the given custom value providers
   static func customFontProvider(
     _ customFontProvider: AnimationFontProvider)

Tests/SnapshotTests.swift

@@ -256,6 +256,10 @@ extension SnapshotConfiguration {
       animationView.imageProvider = customImageProvider
     }
 
+    if let customTextProvider = snapshotConfiguration.customTextProvider {
+      animationView.textProvider = customTextProvider
+    }
+
     if let customFontProvider = snapshotConfiguration.customFontProvider {
       animationView.fontProvider = customFontProvider
     }

Tests/Utils/HardcodedTextProvider.swift

@@ -0,0 +1,27 @@
+// Created by Igor Katselenbogen on 08/19/22.
+// Copyright © 2022 Airbnb Inc. All rights reserved.
+
+import Lottie
+
+// MARK: - HardcodedTextProvider
+
+/// An `AnimationTextProvider` that always returns a specific hardcoded text
+class HardcodedTextProvider: AnimationTextProvider {
+
+  // MARK: Lifecycle
+
+  init(text: String) {
+    self.text = text
+  }
+
+  // MARK: Internal
+
+  func textFor(keypathName _: String, sourceText _: String) -> String {
+    text
+  }
+
+  // MARK: Private
+
+  private let text: String
+
+}

Tests/__Snapshots__/AutomaticEngineTests/testAutomaticEngineDetection.Issues-issue_1722.txt

@@ -0,0 +1 @@
+Supports Core Animation engine

Tests/__Snapshots__/AutomaticEngineTests/testAutomaticEngineDetection.Nonanimating-Text_Glyph.txt

@@ -1,2 +1,3 @@
 Does not support Core Animation engine. Encountered compatibility issues:
+[TEXT] The Core Animation rendering engine does not support animating multiple keyframes for text layer text values (due to limitations of Core Animation `CAKeyframeAnimation`s).
 [TEXT] The Core Animation rendering engine does not support animating multiple keyframes for text layer text values (due to limitations of Core Animation `CAKeyframeAnimation`s).

Tests/__Snapshots__/AutomaticEngineTests/testAutomaticEngineDetection.Nonanimating-Text_NoGlyph.txt

@@ -1,2 +1,3 @@
 Does not support Core Animation engine. Encountered compatibility issues:
+[TEXT] The Core Animation rendering engine does not support animating multiple keyframes for text layer text values (due to limitations of Core Animation `CAKeyframeAnimation`s).
 [TEXT] The Core Animation rendering engine does not support animating multiple keyframes for text layer text values (due to limitations of Core Animation `CAKeyframeAnimation`s).