Parse After Effects blur effects from Lottie files. (#393)

* Parse After Effects blur effects from Lottie files.

Blur is not yet supported in the translator.

source/Issues/LP0008.md

@@ -1,6 +1,5 @@
-[comment]: # (deprecated)
-[comment]: # (name:LayerEffectsIsNotSupported)
-[comment]: # (text:{layer} has an unsupported layer effects, type = {type}.)
+[comment]: # (name:LayerEffectsIsNotSupported)
+[comment]: # (text:{layer} has an unsupported layer effect, type = {type}.)
 
 # Lottie-Windows Warning LP0008
 
@@ -8,7 +7,8 @@ The Lottie file contains Layer Effects. Not all Layer Effects are supported
 by Lottie-Windows.
 
 ## Remarks
-This issue does not apply to the latest version. Please upgrade to a newer version of Lottie-Windows.
+Lottie does not support Layer Effects on most platforms. It may be possible to
+work around this by modifying your After Effects project to avoid the use of Layer Effects.
 
 ## Resources
 

source/LottieData/BlurDimension.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData
+{
+    /// <summary>
+    /// The dimensions affected by a blur.
+    /// </summary>
+#if PUBLIC_LottieData
+    public
+#endif
+    enum BlurDimension
+    {
+        Horizontal,
+        Vertical,
+        HorizontalAndVertical,
+    }
+}

source/LottieData/Effect.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
+
 namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData
 {
     /// <summary>
@@ -31,7 +33,27 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData
 
         public enum EffectType
         {
+            // Type = 25.
             DropShadow,
+
+            // Type = 29.
+            GaussianBlur,
+        }
+
+        /// <summary>
+        /// Represents an effect that was not recognized by the parser.
+        /// </summary>
+        public sealed class Unknown : Effect
+        {
+            readonly double _type;
+
+            public Unknown(double type, string name, bool isEnabled)
+                : base(name, isEnabled)
+            {
+                _type = type;
+            }
+
+            public override EffectType Type => (EffectType)Math.Round(_type);
         }
     }
 }

source/LottieData/Enum.cs

@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+
+using System;
+
+namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData
+{
+    /// <summary>
+    /// Wraps an enum, but implemented as a struct so that
+    /// it can implement <see cref="IEquatable{T}"/> as required by
+    /// <see cref="Animatable{T}"/>.
+    /// </summary>
+    /// <typeparam name="T">An enum type.</typeparam>
+#if PUBLIC_LottieData
+    public
+#endif
+    readonly struct Enum<T> : IEquatable<Enum<T>>
+        where T : struct, IComparable
+    {
+        readonly T _value;
+
+        Enum(T value)
+        {
+            _value = value;
+        }
+
+        public T Value => _value;
+
+        public static implicit operator Enum<T>(T value) => new Enum<T>(value);
+
+        public static implicit operator T(Enum<T> value) => value;
+
+        public bool Equals(Enum<T> other) => other._value.CompareTo(_value) == 0;
+
+        public override string? ToString() => _value.ToString();
+    }
+}

source/LottieData/GaussianBlurEffect.cs

@@ -0,0 +1,47 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData
+{
+    /// <summary>
+    /// A Gaussian blur effect.
+    /// </summary>
+#if PUBLIC_LottieData
+    public
+#endif
+    sealed class GaussianBlurEffect : Effect
+    {
+        public GaussianBlurEffect(
+            string name,
+            bool isEnabled,
+            Animatable<double> blurriness,
+            Animatable<Enum<BlurDimension>> blurDimensions,
+            Animatable<bool> repeatEdgePixels)
+            : base(
+                  name,
+                  isEnabled)
+        {
+            Blurriness = blurriness;
+            BlurDimensions = blurDimensions;
+            RepeatEdgePixels = repeatEdgePixels;
+        }
+
+        /// <summary>
+        /// The intensity of the blur.
+        /// </summary>
+        public Animatable<double> Blurriness { get; }
+
+        /// <summary>
+        /// Whether the blur is horizontal, vertical, or both.
+        /// </summary>
+        public Animatable<Enum<BlurDimension>> BlurDimensions { get; }
+
+        /// <summary>
+        /// Whether or not the blur repeats the pixels at the edge.
+        /// </summary>
+        public Animatable<bool> RepeatEdgePixels { get; }
+
+        public override EffectType Type => EffectType.GaussianBlur;
+    }
+}

source/LottieData/LottieData.projitems

@@ -13,6 +13,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)AssetCollection.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)BezierSegment.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)BlendMode.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)BlurDimension.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Char.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Color.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ColorGradientStop.cs" />
@@ -24,9 +25,11 @@
     <Compile Include="$(MSBuildThisFileDirectory)Effect.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Ellipse.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)EmbeddedImageAsset.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Enum.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ExtensionMethods.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ExternalImageAsset.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Font.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)GaussianBlurEffect.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)GradientStop.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)HoldEasing.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)IAnimatableValue.cs" />

source/LottieData/Serialization/LottieCompositionYamlSerializer.cs

@@ -344,10 +344,14 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
         YamlObject FromEffect(Effect effect, YamlMap superclassContent)
         {
             superclassContent.Add(nameof(effect.Type), effect.Type.ToString());
+            superclassContent.Add(nameof(effect.IsEnabled), effect.IsEnabled);
             return effect.Type switch
             {
                 Effect.EffectType.DropShadow => FromDropShadowEffect((DropShadowEffect)effect, superclassContent),
-                _ => throw Unreachable,
+                Effect.EffectType.GaussianBlur => FromGaussianBlurEffect((GaussianBlurEffect)effect, superclassContent),
+
+                // Handle all unknown effect types.
+                _ => superclassContent,
             };
         }
 
@@ -363,6 +367,15 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
             return result;
         }
 
+        YamlObject FromGaussianBlurEffect(GaussianBlurEffect effect, YamlMap superclassContent)
+        {
+            var result = superclassContent;
+            result.Add(nameof(effect.BlurDimensions), FromAnimatable(effect.BlurDimensions));
+            result.Add(nameof(effect.Blurriness), FromAnimatable(effect.Blurriness));
+            result.Add(nameof(effect.RepeatEdgePixels), FromAnimatable(effect.RepeatEdgePixels));
+            return result;
+        }
+
         YamlObject FromMask(Mask mask)
             => new YamlMap
             {
@@ -468,6 +481,9 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
 
         YamlObject FromAnimatable(Animatable<double> animatable) => FromAnimatable(animatable, Scalar);
 
+        YamlObject FromAnimatable<T>(Animatable<Enum<T>> animatable)
+            where T : struct, IComparable => FromAnimatable(animatable, Scalar);
+
         YamlObject FromAnimatable(Animatable<Opacity> animatable) => FromAnimatable(animatable, Scalar);
 
         YamlObject FromAnimatable(Animatable<Rotation> animatable) => FromAnimatable(animatable, Scalar);
@@ -676,6 +692,9 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
 
         YamlScalar Scalar(Enum type) => Scalar(type, type.ToString());
 
+        YamlObject Scalar<T>(Enum<T> value)
+            where T : struct, IComparable => Scalar(value, value.ToString()!);
+
         YamlScalar Scalar(Mask.MaskMode type) => Scalar(type, type.ToString());
 
         YamlScalar Scalar(Opacity value) => Scalar(value, $"{value.Percent}%");

source/LottieReader/Serialization/Animatables.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Text.Json;
 
@@ -17,6 +16,9 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
         static readonly Sequence<GradientStop> s_defaultGradientStops =
             new Sequence<GradientStop>(new ColorGradientStop(0, Color.Black));
 
+        static readonly Animatable<Enum<BlurDimension>> s_animatableBlurDimensionHorizontalAndVertical =
+            CreateNonAnimatedAnimatable((Enum<BlurDimension>)BlurDimension.HorizontalAndVertical);
+
         static readonly Animatable<Color> s_animatableColorBlack = CreateNonAnimatedAnimatable(Color.Black);
         static readonly Animatable<double> s_animatableDoubleZero = CreateNonAnimatedAnimatable(0.0);
         static readonly Animatable<bool> s_animatableFalse = CreateNonAnimatedAnimatable(false);
@@ -28,6 +30,15 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
         static readonly AnimatableVector3 s_animatableVector3Zero = new AnimatableVector3(Vector3.Zero, null);
         static readonly AnimatableVector3 s_animatableVector3OneHundred = new AnimatableVector3(new Vector3(100, 100, 100), null);
 
+        static readonly AnimatableParser<Enum<BlurDimension>> s_animatableBlurDimensionParser =
+            CreateAnimatableParser((in LottieJsonElement element) => element.AsInt32() switch
+            {
+                1 => (Enum<BlurDimension>)BlurDimension.HorizontalAndVertical,
+                2 => (Enum<BlurDimension>)BlurDimension.Horizontal,
+                3 => (Enum<BlurDimension>)BlurDimension.Vertical,
+                _ => throw ReaderException("Unexpected blur dimension value."),
+            });
+
         // Parses boolean values as 0 or non-0 integers.
         static readonly AnimatableParser<bool> s_animatableBoolParser =
             CreateAnimatableParser((in LottieJsonElement element) => (element.AsInt32() ?? 0) != 0);
@@ -69,6 +80,11 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
                 ? s_animatableFalse
                 : ReadAnimatable(s_animatableBoolParser, obj.Value);
 
+        Animatable<Enum<BlurDimension>> ReadAnimatableBlurDimension(in LottieJsonObjectElement? obj)
+            => obj is null
+                ? s_animatableBlurDimensionHorizontalAndVertical
+                : ReadAnimatable(s_animatableBlurDimensionParser, obj.Value);
+
         Animatable<Color> ReadAnimatableColor(in LottieJsonObjectElement? obj)
             => obj is null
                 ? s_animatableColorBlack

source/LottieReader/Serialization/Effects.cs

@@ -38,29 +38,32 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
 
         Effect? ReadEffect(in LottieJsonObjectElement obj, string layerName)
         {
-            var effectType = obj.DoublePropertyOrNull("ty") ?? throw ReaderException("Invalid effect");
+            var effectType = obj.DoublePropertyOrNull("ty") ?? throw ReaderException("Invalid effect.");
+            var effectName = obj.StringPropertyOrNull("nm") ?? string.Empty;
+            var isEnabled = obj.BoolPropertyOrNull("en") ?? true;
 
             switch (effectType)
             {
-                // DropShadows are type 25. This is the only type we currently support.
                 case 25:
-                    return ReadDropShadowEffect(obj);
+                    return ReadDropShadowEffect(obj, effectName, isEnabled);
+
+                case 29:
+                    return ReadGaussianBlurEffect(obj, effectName, isEnabled);
 
                 default:
                     obj.IgnorePropertyThatIsNotYetSupported(
-                        "nm",   // name.
                         "mn",   // match name.
-                        "en",   // enabled.
                         "np",   // unknown.
                         "ix",   // index.
                         "ef");  // effect parameters.
 
                     _issues.LayerEffectsIsNotSupported(layerName, effectType.ToString());
-                    return null;
+                    return new Effect.Unknown(effectType, effectName, isEnabled);
             }
         }
 
-        DropShadowEffect ReadDropShadowEffect(in LottieJsonObjectElement obj)
+        // Layer effect type 29.
+        GaussianBlurEffect ReadGaussianBlurEffect(in LottieJsonObjectElement obj, string effectName, bool isEnabled)
         {
             // Index.
             obj.IgnorePropertyIntentionally("ix");
@@ -71,9 +74,67 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
             // Unknown.
             obj.IgnorePropertyIntentionally("np");
 
-            var effectName = obj.StringPropertyOrNull("nm") ?? string.Empty;
+            var parameters = obj.ArrayPropertyOrNull("ef") ?? throw ParseFailure();
 
-            var isEnabled = obj.BoolPropertyOrNull("en") ?? true;
+            Animatable<double>? blurriness = null;
+            Animatable<Enum<BlurDimension>>? blurDimensions = null;
+            Animatable<bool>? repeatEdgePixels = null;
+
+            for (var i = 0; i < parameters.Count; i++)
+            {
+                var p = parameters[i].AsObject() ?? throw ParseFailure();
+
+                var value = p.ObjectPropertyOrNull("v") ?? throw ParseFailure();
+
+                switch (i)
+                {
+                    case 0:
+                        // Blurriness - float 0..50
+                        blurriness = ReadAnimatableFloat(value) ?? throw ParseFailure();
+                        break;
+
+                    case 1:
+                        blurDimensions = ReadAnimatableBlurDimension(value) ?? throw ParseFailure();
+                        break;
+
+                    case 2:
+                        repeatEdgePixels = ReadAnimatableBool(value) ?? throw ParseFailure();
+                        break;
+
+                    default:
+                        throw ParseFailure();
+                }
+            }
+
+            // Ensure all parameter values were provided.
+            if (blurriness is null ||
+                blurDimensions is null ||
+                repeatEdgePixels is null)
+            {
+                throw ParseFailure();
+            }
+
+            return new GaussianBlurEffect(
+                effectName,
+                isEnabled,
+                blurriness: blurriness,
+                blurDimensions: blurDimensions,
+                repeatEdgePixels: repeatEdgePixels);
+
+            static Exception ParseFailure() => ReaderException("Invalid Gaussian blur effect.");
+        }
+
+        // Layer effect type 25.
+        DropShadowEffect ReadDropShadowEffect(in LottieJsonObjectElement obj, string effectName, bool isEnabled)
+        {
+            // Index.
+            obj.IgnorePropertyIntentionally("ix");
+
+            // Match name.
+            obj.IgnorePropertyIntentionally("mn");
+
+            // Unknown.
+            obj.IgnorePropertyIntentionally("np");
 
             var parameters = obj.ArrayPropertyOrNull("ef") ?? throw ParseFailure();
 
@@ -112,7 +173,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
                         break;
 
                     default:
-                        throw ReaderException("Invalid drop shadow effect");
+                        throw ParseFailure();
                 }
             }
 
@@ -137,7 +198,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
                 opacity: opacity,
                 softness: softness);
 
-            static Exception ParseFailure() => ReaderException("Invalid drop shadow effect");
+            static Exception ParseFailure() => ReaderException("Invalid drop shadow effect.");
         }
     }
 }

source/LottieReader/Serialization/ParsingIssues.cs

@@ -43,7 +43,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Lottie.LottieData.Serialization
 
         internal void IllustratorLayers() => Report("LP0007", "Illustrator layers.");
 
-        internal void LayerEffectsIsNotSupported(string layer, string type) => Report("LP0008", $"{layer} has an unsupported layer effects, type = {type}.");
+        internal void LayerEffectsIsNotSupported(string layer, string type) => Report("LP0008", $"{layer} has an unsupported layer effect, type = {type}.");
 
         // LP0009 has been deprecated.
         // Was: Mattes.