Added lottie merge optimization (#453)

* Added lottie merge optimization

Author: aborziak-ms

source/Animatables/Animatable.cs

@@ -102,7 +102,7 @@ public Animatable(T initialValue, IReadOnlyList<KeyFrame<T>> keyFrames)
         public bool IsEverNot(T value) => !IsAlways(value);
 
         public Animatable<T> WithTimeOffset(double timeOffset)
-            => timeOffset != 0 || IsAnimated
+            => timeOffset != 0 && IsAnimated
                 ? new Animatable<T>(KeyFrames.Select(kf => kf.WithTimeOffset(timeOffset)))
                 : this;
 

source/Animatables/AnimatableVector2.cs

@@ -30,7 +30,7 @@ public AnimatableVector2 WithOffset(Vector2 offset)
             => Select(vector2 => vector2 + offset);
 
         public new AnimatableVector2 WithTimeOffset(double timeOffset)
-            => timeOffset != 0 || IsAnimated
+            => timeOffset != 0 && IsAnimated
                 ? new AnimatableVector2(KeyFrames.Select(kf => kf.WithTimeOffset(timeOffset)))
                 : this;
 

source/Animatables/AnimatableVector3.cs

@@ -30,7 +30,7 @@ public AnimatableVector3 WithOffset(Vector2 offset)
             => Select(vector3 => vector3 + new Vector3(offset.X, offset.Y, 0));
 
         public new AnimatableVector3 WithTimeOffset(double timeOffset)
-            => timeOffset != 0 || IsAnimated
+            => timeOffset != 0 && IsAnimated
                 ? new AnimatableVector3(KeyFrames.Select(kf => kf.WithTimeOffset(timeOffset)))
                 : this;
 

source/LottieData/Ellipse.cs

@@ -30,5 +30,10 @@ public Ellipse(
         public override ShapeContentType ContentType => ShapeContentType.Ellipse;
 
         public override ShapeType ShapeType => ShapeType.Ellipse;
+
+        public override ShapeLayerContent WithTimeOffset(double offset)
+        {
+            return new Ellipse(CopyArgs(), DrawingDirection, Position.WithTimeOffset(offset), Diameter.WithTimeOffset(offset));
+        }
     }
 }

source/LottieData/ImageLayer.cs

@@ -24,5 +24,15 @@ public ImageLayer(
 
         /// <inheritdoc/>
         public override LayerType Type => LayerType.Image;
+
+        public override Layer WithIndicesChanged(int index, int? parentIndex)
+        {
+            return new ImageLayer(GetArgsWithIndicesChanged(index, parentIndex), RefId);
+        }
+
+        public override Layer WithTimeOffset(double offset)
+        {
+            return new ImageLayer(GetArgsWithTimeOffset(offset), RefId);
+        }
     }
 }

source/LottieData/Layer.cs

@@ -62,7 +62,7 @@ private protected Layer(in LayerArgs args)
         /// <summary>
         /// Gets the list of masks appplied to the layer.
         /// </summary>
-        public IReadOnlyList<Mask> Masks { get; set; }
+        public IReadOnlyList<Mask> Masks { get; }
 
         /// <summary>
         /// Gets the frame at which this <see cref="Layer"/> becomes invisible. <see cref="OutPoint"/>.
@@ -123,6 +123,46 @@ public ref struct LayerArgs
             public MatteType LayerMatteType { get; set; }
         }
 
+        public LayerArgs CopyArgs()
+        {
+            return new LayerArgs
+            {
+                Name = Name,
+                Index = Index,
+                Parent = Parent,
+                IsHidden = IsHidden,
+                Transform = Transform,
+                TimeStretch = TimeStretch,
+                StartFrame = InPoint,
+                InFrame = InPoint,
+                OutFrame = OutPoint,
+                BlendMode = BlendMode,
+                Is3d = Is3d,
+                AutoOrient = AutoOrient,
+                LayerMatteType = LayerMatteType,
+                Effects = Effects,
+                Masks = Masks,
+            };
+        }
+
+        protected LayerArgs GetArgsWithIndicesChanged(int index, int? parentIndex)
+        {
+            var args = CopyArgs();
+            args.Index = index;
+            args.Parent = parentIndex;
+            return args;
+        }
+
+        protected LayerArgs GetArgsWithTimeOffset(double shiftValue)
+        {
+            var args = CopyArgs();
+            args.Transform = (Transform)args.Transform.WithTimeOffset(shiftValue);
+            args.StartFrame += shiftValue;
+            args.InFrame += shiftValue;
+            args.OutFrame += shiftValue;
+            return args;
+        }
+
         public enum LayerType
         {
             PreComp,
@@ -139,5 +179,20 @@ public enum MatteType
             Add,
             Invert,
         }
+
+        /// <summary>
+        /// Make a copy of the layer and change its index and parent index.
+        /// </summary>
+        /// <param name="index">Index to be set.</param>
+        /// <param name="parentIndex">Parent index to be set.</param>
+        /// <returns>Layer copy with changed indices.</returns>
+        public abstract Layer WithIndicesChanged(int index, int? parentIndex);
+
+        /// <summary>
+        /// Make a copy of the layer and offset all frames by some value.
+        /// </summary>
+        /// <param name="offset">Offset value.</param>
+        /// <returns>Layer copy with offsetted frames.</returns>
+        public abstract Layer WithTimeOffset(double offset);
     }
 }

source/LottieData/LayerCollection.cs

@@ -97,5 +97,10 @@ public LayerCollection(IEnumerable<Layer> layers)
             // Not found.
             return null;
         }
+
+        public LayerCollection WithTimeOffset(double offset)
+        {
+            return new LayerCollection(_layers.Select(layer => layer.WithTimeOffset(offset)));
+        }
     }
 }

source/LottieData/LinearGradientFill.cs

@@ -36,5 +36,16 @@ public LinearGradientFill(
 
         /// <inheritdoc/>
         public override ShapeContentType ContentType => ShapeContentType.LinearGradientFill;
+
+        public override ShapeLayerContent WithTimeOffset(double offset)
+        {
+            return new LinearGradientFill(
+                CopyArgs(),
+                FillType,
+                Opacity.WithTimeOffset(offset),
+                StartPoint.WithTimeOffset(offset),
+                EndPoint.WithTimeOffset(offset),
+                GradientStops.WithTimeOffset(offset));
+        }
     }
 }

source/LottieData/LinearGradientStroke.cs

@@ -38,5 +38,20 @@ public LinearGradientStroke(
         public override ShapeContentType ContentType => ShapeContentType.LinearGradientStroke;
 
         public override ShapeStrokeKind StrokeKind => ShapeStrokeKind.LinearGradient;
+
+        public override ShapeLayerContent WithTimeOffset(double offset)
+        {
+            return new LinearGradientStroke(
+                CopyArgs(),
+                Opacity.WithTimeOffset(offset),
+                StrokeWidth.WithTimeOffset(offset),
+                CapType,
+                JoinType,
+                MiterLimit,
+                StartPoint.WithTimeOffset(offset),
+                EndPoint.WithTimeOffset(offset),
+                GradientStops.WithTimeOffset(offset)
+                );
+        }
     }
 }

source/LottieData/LottieData.projitems

@@ -35,8 +35,15 @@
     <Compile Include="$(MSBuildThisFileDirectory)Mask.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)MergePaths.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)NullLayer.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\LayerGroup.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\LayersGraph.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\MergeHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Optimization\GradientStopOptimizer.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\LayersIndexMapper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\LottieMergeOptimizer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Optimization\Optimizer.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\TimeRange.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Optimization\Experimental\MergeResult.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Path.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Polystar.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)PreCompLayer.cs" />