add EasingGeometryKeyFrame

src/Shared/HandyControl_Shared/HandyControl_Shared.projitems

@@ -42,6 +42,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Interactivity\Commands\CloseWindowCommand.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Interactivity\Commands\OpenLinkCommand.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Media\Animation\DiscreteGeometryKeyFrame.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Media\Animation\EasingGeometryKeyFrame.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Media\Animation\GeometryAnimation.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Media\Animation\GeometryAnimationBase.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Media\Animation\GeometryAnimationUsingKeyFrames.cs" />

src/Shared/HandyControl_Shared/Media/Animation/EasingGeometryKeyFrame.cs

@@ -0,0 +1,70 @@
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Animation;
+using HandyControl.Expression.Drawing;
+using HandyControl.Tools;
+
+namespace HandyControl.Media.Animation
+{
+    public class EasingGeometryKeyFrame : GeometryKeyFrame
+    {
+        private double[] _baseValues;
+
+        public EasingGeometryKeyFrame()
+        {
+
+        }
+
+        public EasingGeometryKeyFrame(Geometry value) : base(value)
+        {
+
+        }
+
+        public EasingGeometryKeyFrame(Geometry value, KeyTime keyTime) : base(value, keyTime)
+        {
+
+        }
+
+        public EasingGeometryKeyFrame(Geometry value, KeyTime keyTime, IEasingFunction easingFunction) : base(value, keyTime)
+        {
+            EasingFunction = easingFunction;
+        }
+
+        protected override Freezable CreateInstanceCore() => new EasingGeometryKeyFrame();
+
+        protected override Geometry InterpolateValueCore(Geometry baseValue, double keyFrameProgress)
+        {
+            if (_baseValues == null)
+            {
+                AnimationHelper.DecomposeGeometryStr(baseValue.ToString(), out _baseValues);
+            }
+
+            var easingFunction = EasingFunction;
+            if (easingFunction != null)
+            {
+                keyFrameProgress = easingFunction.Ease(keyFrameProgress);
+            }
+
+            if (MathHelper.IsVerySmall(keyFrameProgress))
+            {
+                return baseValue;
+            }
+
+            if (MathHelper.AreClose(keyFrameProgress, 1))
+            {
+                return AnimationHelper.ComposeGeometry(Strings, Value);
+            }
+
+            return AnimationHelper.InterpolateGeometry(_baseValues, Value, keyFrameProgress, Strings);
+        }
+
+        public static readonly DependencyProperty EasingFunctionProperty = DependencyProperty.Register(
+            "EasingFunction", typeof(IEasingFunction), typeof(EasingGeometryKeyFrame), new PropertyMetadata(default(IEasingFunction)));
+
+        public IEasingFunction EasingFunction
+        {
+            get => (IEasingFunction) GetValue(EasingFunctionProperty);
+            set => SetValue(EasingFunctionProperty, value);
+        }
+    }
+}

src/Shared/HandyControl_Shared/Media/Animation/LinearGeometryKeyFrame.cs

@@ -25,7 +25,7 @@ namespace HandyControl.Media.Animation
 
         }
 
-        protected override Freezable CreateInstanceCore() => new LinearDoubleKeyFrame();
+        protected override Freezable CreateInstanceCore() => new LinearGeometryKeyFrame();
 
         protected override Geometry InterpolateValueCore(Geometry baseValue, double keyFrameProgress)
         {
@@ -44,13 +44,7 @@ namespace HandyControl.Media.Animation
                 return AnimationHelper.ComposeGeometry(Strings, Value);
             }
 
-            var accumulated = new double[Value.Length];
+            return AnimationHelper.InterpolateGeometry(_baseValues, Value, keyFrameProgress, Strings);
-            for (var i = 0; i < Value.Length; i++)
-            {
-                accumulated[i] = _baseValues[i] + (Value[i] - _baseValues[i]) * keyFrameProgress;
-            }
-
-            return AnimationHelper.ComposeGeometry(Strings, accumulated);
         }
     }
 }

src/Shared/HandyControl_Shared/Tools/Helper/AnimationHelper.cs

@@ -66,5 +66,17 @@ namespace HandyControl.Tools
 
             return Geometry.Parse(builder.ToString());
         }
+
+        internal static Geometry InterpolateGeometry(double[] from, double[] to, double progress, string[] strings)
+        {
+            var accumulated = new double[to.Length];
+            for (var i = 0; i < to.Length; i++)
+            {
+                var fromValue = from[i];
+                accumulated[i] = fromValue + (to[i] - fromValue) * progress;
+            }
+
+            return ComposeGeometry(strings, accumulated);
+        }
     }
 }