Blend mode support (#1585)

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

Lottie.xcodeproj/project.pbxproj

@@ -565,6 +565,9 @@
 		6DB3BDC328245AA2002A276D /* ParsingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6DB3BDBF28245A6A002A276D /* ParsingTests.swift */; };
 		6DEF696E2824A76C007D640F /* BundleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6DEF696D2824A76C007D640F /* BundleTests.swift */; };
 		A1D5BAAC27C731A500777D06 /* DataURLTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1D5BAAB27C731A500777D06 /* DataURLTests.swift */; };
+		A40460592832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */ = {isa = PBXBuildFile; fileRef = A40460582832C52B00ACFEDC /* BlendMode+Filter.swift */; };
+		A404605A2832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */ = {isa = PBXBuildFile; fileRef = A40460582832C52B00ACFEDC /* BlendMode+Filter.swift */; };
+		A404605B2832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */ = {isa = PBXBuildFile; fileRef = A40460582832C52B00ACFEDC /* BlendMode+Filter.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -777,6 +780,7 @@
 		6DB3BDBF28245A6A002A276D /* ParsingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ParsingTests.swift; sourceTree = "<group>"; };
 		6DEF696D2824A76C007D640F /* BundleTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BundleTests.swift; sourceTree = "<group>"; };
 		A1D5BAAB27C731A500777D06 /* DataURLTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataURLTests.swift; sourceTree = "<group>"; };
+		A40460582832C52B00ACFEDC /* BlendMode+Filter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "BlendMode+Filter.swift"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -1258,6 +1262,7 @@
 		2E9C95C02822F43100677516 /* Extensions */ = {
 			isa = PBXGroup;
 			children = (
+				A40460582832C52B00ACFEDC /* BlendMode+Filter.swift */,
 				2E9C95C12822F43100677516 /* CGFloatExtensions.swift */,
 				2E9C95C22822F43100677516 /* CGColor+RGB.swift */,
 				2E9C95C32822F43100677516 /* AnimationKeypathExtension.swift */,
@@ -1830,6 +1835,7 @@
 				2EAF5AE027A0798700E00531 /* Keyframe.swift in Sources */,
 				2E9C960F2822F43100677516 /* Animation.swift in Sources */,
 				2E9C969C2822F43100677516 /* StarNode.swift in Sources */,
+				A40460592832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */,
 				2E9C96542822F43100677516 /* ImageCompositionLayer.swift in Sources */,
 				2EAF5AB327A0798700E00531 /* AnimationImageProvider.swift in Sources */,
 				2E9C95F12822F43100677516 /* GradientStroke.swift in Sources */,
@@ -2037,6 +2043,7 @@
 				2EAF5AE127A0798700E00531 /* Keyframe.swift in Sources */,
 				2E9C96102822F43100677516 /* Animation.swift in Sources */,
 				2E9C969D2822F43100677516 /* StarNode.swift in Sources */,
+				A404605A2832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */,
 				2E9C96552822F43100677516 /* ImageCompositionLayer.swift in Sources */,
 				2EAF5AB427A0798700E00531 /* AnimationImageProvider.swift in Sources */,
 				2E9C95F22822F43100677516 /* GradientStroke.swift in Sources */,
@@ -2224,6 +2231,7 @@
 				2EAF5AE227A0798700E00531 /* Keyframe.swift in Sources */,
 				2E9C96112822F43100677516 /* Animation.swift in Sources */,
 				2E9C969E2822F43100677516 /* StarNode.swift in Sources */,
+				A404605B2832C52B00ACFEDC /* BlendMode+Filter.swift in Sources */,
 				2E9C96562822F43100677516 /* ImageCompositionLayer.swift in Sources */,
 				2EAF5AB527A0798700E00531 /* AnimationImageProvider.swift in Sources */,
 				2E9C95F32822F43100677516 /* GradientStroke.swift in Sources */,

Sources/Private/CoreAnimation/Layers/BaseCompositionLayer.swift

@@ -15,6 +15,7 @@ class BaseCompositionLayer: BaseAnimationLayer {
     super.init()
 
     setupSublayers()
+    compositingFilter = layerModel.blendMode.filterName
     name = layerModel.name
   }
 

Sources/Private/MainThread/LayerContainers/CompLayers/CompositionLayer.swift

@@ -49,6 +49,7 @@ class CompositionLayer: CALayer, KeypathSearchable {
       "sublayerTransform" : NSNull(),
       "hidden" : NSNull(),
     ]
+    compositingFilter = layer.blendMode.filterName
     addSublayer(contentsLayer)
 
     if let maskLayer = maskLayer {

Sources/Private/Utility/Extensions/BlendMode+Filter.swift

@@ -0,0 +1,31 @@
+//
+//  File.swift
+//
+//
+//  Created by Denis Koryttsev on 10.05.2022.
+//
+
+extension BlendMode {
+  /// The Core Image filter name for this `BlendMode`, that can be applied to a `CALayer`'s `compositingFilter`.
+  /// Supported compositing filters are defined here: https://developer.apple.com/library/archive/documentation/GraphicsImaging/Reference/CoreImageFilterReference/index.html#//apple_ref/doc/uid/TP30000136-SW71
+  var filterName: String? {
+    switch self {
+    case .normal: return nil
+    case .multiply: return "multiplyBlendMode"
+    case .screen: return "screenBlendMode"
+    case .overlay: return "overlayBlendMode"
+    case .darken: return "darkenBlendMode"
+    case .lighten: return "lightenBlendMode"
+    case .colorDodge: return "colorDodgeBlendMode"
+    case .colorBurn: return "colorBurnBlendMode"
+    case .hardLight: return "hardLightBlendMode"
+    case .softLight: return "softLightBlendMode"
+    case .difference: return "differenceBlendMode"
+    case .exclusion: return "exclusionBlendMode"
+    case .hue: return "hueBlendMode"
+    case .saturation: return "saturationBlendMode"
+    case .color: return "colorBlendMode"
+    case .luminosity: return "luminosityBlendMode"
+    }
+  }
+}

Tests/SnapshotConfiguration.swift

@@ -43,6 +43,7 @@ extension SnapshotConfiguration {
     "Issues/issue_1407": .precision(0.9),
     "Nonanimating/FirstText": .precision(0.99),
     "Nonanimating/verifyLineHeight": .precision(0.99),
+    "Nonanimating/blend_mode_test": .precision(0.99),
 
     /// Test cases for the `AnimationKeypath` / `AnyValueProvider` system
     "Nonanimating/keypathTest": .customValueProviders([