From bb7873ef66df2206df10be0f886d418e0c62fe1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Sat, 9 Aug 2025 23:00:15 +0800
Subject: [PATCH 1/6] feat:Implements subtle animations for the NavMenu in a
 non-intrusive way.

---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs     | 11 +++
 .../Controls/NavMenu/WHAnimationHelper.cs     | 78 +++++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 src/Ursa/Controls/NavMenu/WHAnimationHelper.cs

diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
index 6e78ad8..ec9ec24 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
@@ -1,11 +1,22 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Ursa.Controls;
 
 namespace Ursa.Demo.Pages;
 
 public partial class NavMenuDemo : UserControl
 {
+    private readonly WHAnimationHelper _animationHelper;
+
     public NavMenuDemo()
     {
         InitializeComponent();
+        _animationHelper = new WHAnimationHelper(menu, NavMenu.IsHorizontalCollapsedProperty);
+    }
+
+    protected override void OnLoaded(RoutedEventArgs e)
+    {
+        base.OnLoaded(e);
+        _animationHelper.Start();
     }
 }
\ No newline at end of file
diff --git a/src/Ursa/Controls/NavMenu/WHAnimationHelper.cs b/src/Ursa/Controls/NavMenu/WHAnimationHelper.cs
new file mode 100644
index 0000000..649a8d6
--- /dev/null
+++ b/src/Ursa/Controls/NavMenu/WHAnimationHelper.cs
@@ -0,0 +1,78 @@
+using Avalonia;
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.Styling;
+using Avalonia.Threading;
+using Avalonia.VisualTree;
+
+namespace Ursa.Controls;
+
+public class WHAnimationHelper(Control control, AvaloniaProperty property)
+{
+    private CancellationTokenSource? _cancellationTokenSource;
+
+    ~WHAnimationHelper()
+    {
+        _cancellationTokenSource?.Dispose();
+    }
+
+    public void Stop()
+    {
+        control.PropertyChanged -= AnimationTargetOnPropertyChanged;
+    }
+
+    public void Start()
+    {
+        control.PropertyChanged += AnimationTargetOnPropertyChanged;
+    }
+
+    private void AnimationTargetOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
+    {
+        if (sender as Control != control ||
+            e.Property != property ||
+            control.IsLoaded is false ||
+            control.IsVisible is false) return;
+        _cancellationTokenSource?.Cancel();
+        _cancellationTokenSource?.Dispose();
+        _cancellationTokenSource = new CancellationTokenSource();
+
+        var oldValue = control.DesiredSize;
+        control.UpdateLayout();
+        var newValue = control.DesiredSize;
+        newValue = newValue.WithWidth(newValue.Width + 20);
+        control.InvalidateArrange();
+        var animation = CreateAnimation(oldValue, newValue);
+        animation.RunAsync(control, _cancellationTokenSource.Token);
+    }
+
+    protected virtual Animation CreateAnimation(Size oldValue, Size newValue)
+    {
+        return new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(300),
+            Easing = new CubicEaseInOut(),
+            FillMode = FillMode.None,
+            Children =
+            {
+                new KeyFrame
+                {
+                    Cue = new Cue(0.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, oldValue.Width)
+                    }
+                },
+                new KeyFrame
+                {
+                    Cue = new Cue(1.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, newValue.Width)
+                    }
+                }
+            }
+        };
+    }
+}
\ No newline at end of file

From c801c4eec4804a5c8e585e7e94b00276687ef74f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Sun, 10 Aug 2025 00:00:30 +0800
Subject: [PATCH 2/6] misc:Refactor the WHAnimationHelper class structure to
 clearly define its responsibilities.

---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs     |  5 +-
 src/Ursa/Helpers/NavMenuAnimationHelper.cs    | 46 +++++++++++++++++++
 .../NavMenu => Helpers}/WHAnimationHelper.cs  |  3 +-
 3 files changed, 50 insertions(+), 4 deletions(-)
 create mode 100644 src/Ursa/Helpers/NavMenuAnimationHelper.cs
 rename src/Ursa/{Controls/NavMenu => Helpers}/WHAnimationHelper.cs (96%)

diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
index ec9ec24..aff3e1b 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
@@ -1,17 +1,18 @@
 using Avalonia.Controls;
 using Avalonia.Interactivity;
 using Ursa.Controls;
+using Ursa.Helpers;
 
 namespace Ursa.Demo.Pages;
 
 public partial class NavMenuDemo : UserControl
 {
-    private readonly WHAnimationHelper _animationHelper;
+    private readonly NavMenuAnimationHelper _animationHelper;
 
     public NavMenuDemo()
     {
         InitializeComponent();
-        _animationHelper = new WHAnimationHelper(menu, NavMenu.IsHorizontalCollapsedProperty);
+        _animationHelper = new NavMenuAnimationHelper(menu);
     }
 
     protected override void OnLoaded(RoutedEventArgs e)
diff --git a/src/Ursa/Helpers/NavMenuAnimationHelper.cs b/src/Ursa/Helpers/NavMenuAnimationHelper.cs
new file mode 100644
index 0000000..5848792
--- /dev/null
+++ b/src/Ursa/Helpers/NavMenuAnimationHelper.cs
@@ -0,0 +1,46 @@
+using Avalonia;
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.Styling;
+using Ursa.Controls;
+
+namespace Ursa.Helpers;
+
+public class NavMenuAnimationHelper(NavMenu control) : WHAnimationHelper(control, NavMenu.IsHorizontalCollapsedProperty)
+{
+    protected override Animation CreateAnimation(Size oldValue, Size newValue)
+    {
+        if (oldValue.Width > newValue.Width)
+        {
+            newValue = newValue.WithWidth(newValue.Width + 20);
+        }
+
+        return new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(300),
+            Easing = new CubicEaseInOut(),
+            FillMode = FillMode.None,
+            Children =
+            {
+                new KeyFrame
+                {
+                    Cue = new Cue(0.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, oldValue.Width)
+                    }
+                },
+                new KeyFrame
+                {
+                    Cue = new Cue(1.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, newValue.Width)
+                    }
+                }
+            }
+        };
+    }
+}
\ No newline at end of file
diff --git a/src/Ursa/Controls/NavMenu/WHAnimationHelper.cs b/src/Ursa/Helpers/WHAnimationHelper.cs
similarity index 96%
rename from src/Ursa/Controls/NavMenu/WHAnimationHelper.cs
rename to src/Ursa/Helpers/WHAnimationHelper.cs
index 649a8d6..d583b3c 100644
--- a/src/Ursa/Controls/NavMenu/WHAnimationHelper.cs
+++ b/src/Ursa/Helpers/WHAnimationHelper.cs
@@ -7,7 +7,7 @@ using Avalonia.Styling;
 using Avalonia.Threading;
 using Avalonia.VisualTree;
 
-namespace Ursa.Controls;
+namespace Ursa.Helpers;
 
 public class WHAnimationHelper(Control control, AvaloniaProperty property)
 {
@@ -41,7 +41,6 @@ public class WHAnimationHelper(Control control, AvaloniaProperty property)
         var oldValue = control.DesiredSize;
         control.UpdateLayout();
         var newValue = control.DesiredSize;
-        newValue = newValue.WithWidth(newValue.Width + 20);
         control.InvalidateArrange();
         var animation = CreateAnimation(oldValue, newValue);
         animation.RunAsync(control, _cancellationTokenSource.Token);

From b9e104a8b82ec3edbded1f4284c3800910045efa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Sun, 10 Aug 2025 16:37:03 +0800
Subject: [PATCH 3/6] feat:Redesign the usage pattern of WHAnimationHelper once
 more to deliver a superior axaml editing and consumption experience.

---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml     |   6 +-
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs  |  49 +++++--
 src/Ursa/Helpers/NavMenuAnimationHelper.cs |  46 -------
 src/Ursa/Helpers/WHAnimationHelper.cs      | 152 ++++++++++++++++-----
 4 files changed, 160 insertions(+), 93 deletions(-)
 delete mode 100644 src/Ursa/Helpers/NavMenuAnimationHelper.cs

diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
index 424e03a..81d75cf 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
@@ -8,6 +8,7 @@
     xmlns:u="https://irihi.tech/ursa"
     xmlns:vm="using:Ursa.Demo.ViewModels"
     xmlns:iri="https://irihi.tech/shared"
+    xmlns:views="using:Ursa.Demo.Pages"
     d:DesignHeight="450"
     d:DesignWidth="800"
     x:CompileBindings="True"
@@ -39,7 +40,10 @@
                 IsHorizontalCollapsed="{Binding #collapse.IsChecked, Mode=OneWay}"
                 ItemsSource="{Binding MenuItems}"
                 SelectedItem="{Binding SelectedMenuItem}"
-                SubMenuBinding="{Binding Children}">
+                SubMenuBinding="{Binding Children}"
+                u:WHAnimationHelper.TriggerAvaloniaProperty="{x:Static u:NavMenu.IsHorizontalCollapsedProperty}"
+                u:WHAnimationHelper.CreateAnimation="{x:Static views:NavMenuDemo.NavMenuAnimation}"
+                u:WHAnimationHelper.EnableWHAnimation="True">
                 <u:NavMenu.Styles>
                     <Style x:DataType="vm:MenuItem" Selector="u|NavMenuItem">
                         <Setter Property="IsSeparator" Value="{Binding IsSeparator}" />
diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
index aff3e1b..1dd61a4 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
@@ -1,5 +1,11 @@
-using Avalonia.Controls;
+using System;
+using Avalonia;
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.Styling;
 using Ursa.Controls;
 using Ursa.Helpers;
 
@@ -7,17 +13,42 @@ namespace Ursa.Demo.Pages;
 
 public partial class NavMenuDemo : UserControl
 {
-    private readonly NavMenuAnimationHelper _animationHelper;
-
     public NavMenuDemo()
     {
         InitializeComponent();
-        _animationHelper = new NavMenuAnimationHelper(menu);
     }
 
-    protected override void OnLoaded(RoutedEventArgs e)
-    {
-        base.OnLoaded(e);
-        _animationHelper.Start();
-    }
+    public static WHAnimationHelperCreateAnimationDelegate NavMenuAnimation { get; } =
+        (_, oldDesiredSize, newDesiredSize) =>
+        {
+            if (oldDesiredSize.Width > newDesiredSize.Width)
+                newDesiredSize = newDesiredSize.WithWidth(newDesiredSize.Width + 20);
+            return new Animation
+            {
+                Duration = TimeSpan.FromMilliseconds(300),
+                Easing = new CubicEaseInOut(),
+                FillMode = FillMode.None,
+                Children =
+                {
+                    new KeyFrame
+                    {
+                        Cue = new Cue(0.0),
+                        Setters =
+                        {
+                            new Setter(WidthProperty, oldDesiredSize.Width),
+                            new Setter(HeightProperty, oldDesiredSize.Height)
+                        }
+                    },
+                    new KeyFrame
+                    {
+                        Cue = new Cue(1.0),
+                        Setters =
+                        {
+                            new Setter(WidthProperty, newDesiredSize.Width),
+                            new Setter(HeightProperty, newDesiredSize.Height)
+                        }
+                    }
+                }
+            };
+        };
 }
\ No newline at end of file
diff --git a/src/Ursa/Helpers/NavMenuAnimationHelper.cs b/src/Ursa/Helpers/NavMenuAnimationHelper.cs
deleted file mode 100644
index 5848792..0000000
--- a/src/Ursa/Helpers/NavMenuAnimationHelper.cs
+++ /dev/null
@@ -1,46 +0,0 @@
-using Avalonia;
-using Avalonia.Animation;
-using Avalonia.Animation.Easings;
-using Avalonia.Controls;
-using Avalonia.Layout;
-using Avalonia.Styling;
-using Ursa.Controls;
-
-namespace Ursa.Helpers;
-
-public class NavMenuAnimationHelper(NavMenu control) : WHAnimationHelper(control, NavMenu.IsHorizontalCollapsedProperty)
-{
-    protected override Animation CreateAnimation(Size oldValue, Size newValue)
-    {
-        if (oldValue.Width > newValue.Width)
-        {
-            newValue = newValue.WithWidth(newValue.Width + 20);
-        }
-
-        return new Animation
-        {
-            Duration = TimeSpan.FromMilliseconds(300),
-            Easing = new CubicEaseInOut(),
-            FillMode = FillMode.None,
-            Children =
-            {
-                new KeyFrame
-                {
-                    Cue = new Cue(0.0),
-                    Setters =
-                    {
-                        new Setter(Layoutable.WidthProperty, oldValue.Width)
-                    }
-                },
-                new KeyFrame
-                {
-                    Cue = new Cue(1.0),
-                    Setters =
-                    {
-                        new Setter(Layoutable.WidthProperty, newValue.Width)
-                    }
-                }
-            }
-        };
-    }
-}
\ No newline at end of file
diff --git a/src/Ursa/Helpers/WHAnimationHelper.cs b/src/Ursa/Helpers/WHAnimationHelper.cs
index d583b3c..c39e9e4 100644
--- a/src/Ursa/Helpers/WHAnimationHelper.cs
+++ b/src/Ursa/Helpers/WHAnimationHelper.cs
@@ -2,51 +2,34 @@
 using Avalonia.Animation;
 using Avalonia.Animation.Easings;
 using Avalonia.Controls;
+using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.Styling;
-using Avalonia.Threading;
-using Avalonia.VisualTree;
 
 namespace Ursa.Helpers;
 
-public class WHAnimationHelper(Control control, AvaloniaProperty property)
+public delegate Animation WHAnimationHelperCreateAnimationDelegate(Control animationTargetControl, Size oldDesiredSize,
+    Size newDesiredSize);
+
+public class WHAnimationHelper : AvaloniaObject
 {
-    private CancellationTokenSource? _cancellationTokenSource;
+    public static readonly AttachedProperty<WHAnimationHelperCreateAnimationDelegate> CreateAnimationProperty =
+        AvaloniaProperty
+            .RegisterAttached<WHAnimationHelper, Control, WHAnimationHelperCreateAnimationDelegate>(
+                "CreateAnimation", CreateAnimationPropertyDefaultValue);
 
-    ~WHAnimationHelper()
-    {
-        _cancellationTokenSource?.Dispose();
-    }
+    internal static readonly AttachedProperty<CancellationTokenSource?> AnimationCancellationTokenSourceProperty =
+        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, CancellationTokenSource?>(
+            "AnimationCancellationTokenSource");
 
-    public void Stop()
-    {
-        control.PropertyChanged -= AnimationTargetOnPropertyChanged;
-    }
+    public static readonly AttachedProperty<AvaloniaProperty?> TriggerAvaloniaPropertyProperty =
+        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, AvaloniaProperty?>("TriggerAvaloniaProperty");
 
-    public void Start()
-    {
-        control.PropertyChanged += AnimationTargetOnPropertyChanged;
-    }
+    public static readonly AttachedProperty<bool> EnableWHAnimationProperty =
+        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, bool>("EnableWHAnimation");
 
-    private void AnimationTargetOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
-    {
-        if (sender as Control != control ||
-            e.Property != property ||
-            control.IsLoaded is false ||
-            control.IsVisible is false) return;
-        _cancellationTokenSource?.Cancel();
-        _cancellationTokenSource?.Dispose();
-        _cancellationTokenSource = new CancellationTokenSource();
-
-        var oldValue = control.DesiredSize;
-        control.UpdateLayout();
-        var newValue = control.DesiredSize;
-        control.InvalidateArrange();
-        var animation = CreateAnimation(oldValue, newValue);
-        animation.RunAsync(control, _cancellationTokenSource.Token);
-    }
-
-    protected virtual Animation CreateAnimation(Size oldValue, Size newValue)
+    private static Animation CreateAnimationPropertyDefaultValue(Control animationTargetControl, Size oldDesiredSize,
+        Size newDesiredSize)
     {
         return new Animation
         {
@@ -60,7 +43,8 @@ public class WHAnimationHelper(Control control, AvaloniaProperty property)
                     Cue = new Cue(0.0),
                     Setters =
                     {
-                        new Setter(Layoutable.WidthProperty, oldValue.Width)
+                        new Setter(Layoutable.WidthProperty, oldDesiredSize.Width),
+                        new Setter(Layoutable.HeightProperty, oldDesiredSize.Height)
                     }
                 },
                 new KeyFrame
@@ -68,10 +52,104 @@ public class WHAnimationHelper(Control control, AvaloniaProperty property)
                     Cue = new Cue(1.0),
                     Setters =
                     {
-                        new Setter(Layoutable.WidthProperty, newValue.Width)
+                        new Setter(Layoutable.WidthProperty, newDesiredSize.Width),
+                        new Setter(Layoutable.HeightProperty, newDesiredSize.Height)
                     }
                 }
             }
         };
     }
+
+
+    public static void SetCreateAnimation(Control obj, WHAnimationHelperCreateAnimationDelegate value)
+    {
+        obj.SetValue(CreateAnimationProperty, value);
+    }
+
+    public static WHAnimationHelperCreateAnimationDelegate GetCreateAnimation(Control obj)
+    {
+        return obj.GetValue(CreateAnimationProperty);
+    }
+
+    internal static void SetAnimationCancellationTokenSource(Control obj, CancellationTokenSource? value)
+    {
+        obj.SetValue(AnimationCancellationTokenSourceProperty, value);
+    }
+
+    internal static CancellationTokenSource? GetAnimationCancellationTokenSource(Control obj)
+    {
+        return obj.GetValue(AnimationCancellationTokenSourceProperty);
+    }
+
+    public static void SetTriggerAvaloniaProperty(Control obj, AvaloniaProperty? value)
+    {
+        obj.SetValue(TriggerAvaloniaPropertyProperty, value);
+    }
+
+    public static AvaloniaProperty? GetTriggerAvaloniaProperty(Control obj)
+    {
+        return obj.GetValue(TriggerAvaloniaPropertyProperty);
+    }
+
+    public static void SetEnableWHAnimation(Control obj, bool value)
+    {
+        if (value == obj.GetValue(EnableWHAnimationProperty)) return;
+        obj.SetValue(EnableWHAnimationProperty, value);
+        if (value)
+        {
+            var triggerProperty = GetTriggerAvaloniaProperty(obj);
+            if (triggerProperty == null)
+            {
+                throw new InvalidOperationException(
+                    "WHAnimationHelper requires TriggerAvaloniaProperty to be set when EnableWHAnimation is true.");
+            }
+
+            if (triggerProperty == Visual.BoundsProperty ||
+                triggerProperty == Layoutable.DesiredSizeProperty)
+            {
+                throw new InvalidOperationException(
+                    "WHAnimationHelper does not support Visual.BoundsProperty or Layoutable.DesiredSizeProperty as trigger property.");
+            }
+
+            obj.Loaded += ObjOnLoaded;
+        }
+        else
+        {
+            obj.Loaded -= ObjOnLoaded;
+            obj.PropertyChanged -= AnimationTargetOnPropertyChanged;
+        }
+
+        void ObjOnLoaded(object? sender, RoutedEventArgs e)
+        {
+            obj.PropertyChanged += AnimationTargetOnPropertyChanged;
+            obj.Loaded -= ObjOnLoaded;
+        }
+    }
+
+    public static bool GetEnableWHAnimation(Control obj)
+    {
+        return obj.GetValue(EnableWHAnimationProperty);
+    }
+
+    private static void AnimationTargetOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
+    {
+        if (sender is not Control control ||
+            GetEnableWHAnimation(control) is false ||
+            e.Property != GetTriggerAvaloniaProperty(control) ||
+            e.Property == Visual.BoundsProperty ||
+            control.IsLoaded is false ||
+            control.IsVisible is false) return;
+        var cancellationTokenSource = GetAnimationCancellationTokenSource(control);
+        cancellationTokenSource?.Cancel();
+        cancellationTokenSource?.Dispose();
+        cancellationTokenSource = new CancellationTokenSource();
+        SetAnimationCancellationTokenSource(control, cancellationTokenSource);
+
+        var oldValue = control.DesiredSize;
+        control.UpdateLayout();
+        var newValue = control.DesiredSize;
+        control.InvalidateArrange();
+        var animation = GetCreateAnimation(control)(control, oldValue, newValue);
+        animation.RunAsync(control, cancellationTokenSource.Token);
+    }
 }
\ No newline at end of file

From df23e6263cb30c560f06adc37529ad30848f910c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Mon, 18 Aug 2025 22:06:47 +0800
Subject: [PATCH 4/6] =?UTF-8?q?misc:Rename=20WHAnimationHelper=20to=20Size?=
 =?UTF-8?q?AnimationHelper=20to=20make=20its=20purpose=20immediately=20cle?=
 =?UTF-8?q?ar=20and=20eliminate=20any=20ambiguity=20caused=20by=20the=20cr?=
 =?UTF-8?q?yptic=20=E2=80=9CWH.=E2=80=9D?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml        |  6 ++---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs     |  2 +-
 ...mationHelper.cs => SizeAnimationHelper.cs} | 22 +++++++++----------
 3 files changed, 15 insertions(+), 15 deletions(-)
 rename src/Ursa/Helpers/{WHAnimationHelper.cs => SizeAnimationHelper.cs} (80%)

diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
index 81d75cf..906b6e4 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
@@ -41,9 +41,9 @@
                 ItemsSource="{Binding MenuItems}"
                 SelectedItem="{Binding SelectedMenuItem}"
                 SubMenuBinding="{Binding Children}"
-                u:WHAnimationHelper.TriggerAvaloniaProperty="{x:Static u:NavMenu.IsHorizontalCollapsedProperty}"
-                u:WHAnimationHelper.CreateAnimation="{x:Static views:NavMenuDemo.NavMenuAnimation}"
-                u:WHAnimationHelper.EnableWHAnimation="True">
+                u:SizeAnimationHelper.TriggerAvaloniaProperty="{x:Static u:NavMenu.IsHorizontalCollapsedProperty}"
+                u:SizeAnimationHelper.CreateAnimation="{x:Static views:NavMenuDemo.NavMenuAnimation}"
+                u:SizeAnimationHelper.EnableWHAnimation="True">
                 <u:NavMenu.Styles>
                     <Style x:DataType="vm:MenuItem" Selector="u|NavMenuItem">
                         <Setter Property="IsSeparator" Value="{Binding IsSeparator}" />
diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
index 1dd61a4..368187b 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
@@ -18,7 +18,7 @@ public partial class NavMenuDemo : UserControl
         InitializeComponent();
     }
 
-    public static WHAnimationHelperCreateAnimationDelegate NavMenuAnimation { get; } =
+    public static SizeAnimationHelperAnimationGeneratorDelegate NavMenuAnimation { get; } =
         (_, oldDesiredSize, newDesiredSize) =>
         {
             if (oldDesiredSize.Width > newDesiredSize.Width)
diff --git a/src/Ursa/Helpers/WHAnimationHelper.cs b/src/Ursa/Helpers/SizeAnimationHelper.cs
similarity index 80%
rename from src/Ursa/Helpers/WHAnimationHelper.cs
rename to src/Ursa/Helpers/SizeAnimationHelper.cs
index c39e9e4..6fc2a2b 100644
--- a/src/Ursa/Helpers/WHAnimationHelper.cs
+++ b/src/Ursa/Helpers/SizeAnimationHelper.cs
@@ -8,25 +8,25 @@ using Avalonia.Styling;
 
 namespace Ursa.Helpers;
 
-public delegate Animation WHAnimationHelperCreateAnimationDelegate(Control animationTargetControl, Size oldDesiredSize,
+public delegate Animation SizeAnimationHelperAnimationGeneratorDelegate(Control animationTargetControl, Size oldDesiredSize,
     Size newDesiredSize);
 
-public class WHAnimationHelper : AvaloniaObject
+public class SizeAnimationHelper : AvaloniaObject
 {
-    public static readonly AttachedProperty<WHAnimationHelperCreateAnimationDelegate> CreateAnimationProperty =
+    public static readonly AttachedProperty<SizeAnimationHelperAnimationGeneratorDelegate> CreateAnimationProperty =
         AvaloniaProperty
-            .RegisterAttached<WHAnimationHelper, Control, WHAnimationHelperCreateAnimationDelegate>(
+            .RegisterAttached<SizeAnimationHelper, Control, SizeAnimationHelperAnimationGeneratorDelegate>(
                 "CreateAnimation", CreateAnimationPropertyDefaultValue);
 
     internal static readonly AttachedProperty<CancellationTokenSource?> AnimationCancellationTokenSourceProperty =
-        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, CancellationTokenSource?>(
+        AvaloniaProperty.RegisterAttached<SizeAnimationHelper, Control, CancellationTokenSource?>(
             "AnimationCancellationTokenSource");
 
     public static readonly AttachedProperty<AvaloniaProperty?> TriggerAvaloniaPropertyProperty =
-        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, AvaloniaProperty?>("TriggerAvaloniaProperty");
+        AvaloniaProperty.RegisterAttached<SizeAnimationHelper, Control, AvaloniaProperty?>("TriggerAvaloniaProperty");
 
     public static readonly AttachedProperty<bool> EnableWHAnimationProperty =
-        AvaloniaProperty.RegisterAttached<WHAnimationHelper, Control, bool>("EnableWHAnimation");
+        AvaloniaProperty.RegisterAttached<SizeAnimationHelper, Control, bool>("EnableWHAnimation");
 
     private static Animation CreateAnimationPropertyDefaultValue(Control animationTargetControl, Size oldDesiredSize,
         Size newDesiredSize)
@@ -61,12 +61,12 @@ public class WHAnimationHelper : AvaloniaObject
     }
 
 
-    public static void SetCreateAnimation(Control obj, WHAnimationHelperCreateAnimationDelegate value)
+    public static void SetCreateAnimation(Control obj, SizeAnimationHelperAnimationGeneratorDelegate value)
     {
         obj.SetValue(CreateAnimationProperty, value);
     }
 
-    public static WHAnimationHelperCreateAnimationDelegate GetCreateAnimation(Control obj)
+    public static SizeAnimationHelperAnimationGeneratorDelegate GetCreateAnimation(Control obj)
     {
         return obj.GetValue(CreateAnimationProperty);
     }
@@ -101,14 +101,14 @@ public class WHAnimationHelper : AvaloniaObject
             if (triggerProperty == null)
             {
                 throw new InvalidOperationException(
-                    "WHAnimationHelper requires TriggerAvaloniaProperty to be set when EnableWHAnimation is true.");
+                    "SizeAnimationHelper requires TriggerAvaloniaProperty to be set when EnableWHAnimation is true.");
             }
 
             if (triggerProperty == Visual.BoundsProperty ||
                 triggerProperty == Layoutable.DesiredSizeProperty)
             {
                 throw new InvalidOperationException(
-                    "WHAnimationHelper does not support Visual.BoundsProperty or Layoutable.DesiredSizeProperty as trigger property.");
+                    "SizeAnimationHelper does not support Visual.BoundsProperty or Layoutable.DesiredSizeProperty as trigger property.");
             }
 
             obj.Loaded += ObjOnLoaded;

From 2345c8a9de06154bbd9464b611fa7bb498123d18 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Mon, 18 Aug 2025 23:09:51 +0800
Subject: [PATCH 5/6] fix:Fix the issue where
 `SizeAnimationHelper.EnableAnimation` is not properly loaded when used via
 the styling system.

---
 src/Ursa/Helpers/SizeAnimationHelper.cs | 38 +++++++++++++++++++------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/src/Ursa/Helpers/SizeAnimationHelper.cs b/src/Ursa/Helpers/SizeAnimationHelper.cs
index 6fc2a2b..d2fc74a 100644
--- a/src/Ursa/Helpers/SizeAnimationHelper.cs
+++ b/src/Ursa/Helpers/SizeAnimationHelper.cs
@@ -1,4 +1,6 @@
-using Avalonia;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices.ComTypes;
+using Avalonia;
 using Avalonia.Animation;
 using Avalonia.Animation.Easings;
 using Avalonia.Controls;
@@ -8,7 +10,8 @@ using Avalonia.Styling;
 
 namespace Ursa.Helpers;
 
-public delegate Animation SizeAnimationHelperAnimationGeneratorDelegate(Control animationTargetControl, Size oldDesiredSize,
+public delegate Animation SizeAnimationHelperAnimationGeneratorDelegate(Control animationTargetControl,
+    Size oldDesiredSize,
     Size newDesiredSize);
 
 public class SizeAnimationHelper : AvaloniaObject
@@ -28,6 +31,11 @@ public class SizeAnimationHelper : AvaloniaObject
     public static readonly AttachedProperty<bool> EnableWHAnimationProperty =
         AvaloniaProperty.RegisterAttached<SizeAnimationHelper, Control, bool>("EnableWHAnimation");
 
+    static SizeAnimationHelper()
+    {
+        EnableWHAnimationProperty.Changed.AddClassHandler<Control>(OnPropertyChanged);
+    }
+    
     private static Animation CreateAnimationPropertyDefaultValue(Control animationTargetControl, Size oldDesiredSize,
         Size newDesiredSize)
     {
@@ -93,8 +101,18 @@ public class SizeAnimationHelper : AvaloniaObject
 
     public static void SetEnableWHAnimation(Control obj, bool value)
     {
-        if (value == obj.GetValue(EnableWHAnimationProperty)) return;
         obj.SetValue(EnableWHAnimationProperty, value);
+    }
+
+    public static bool GetEnableWHAnimation(Control obj)
+    {
+        return obj.GetValue(EnableWHAnimationProperty);
+    }
+
+    private static void OnPropertyChanged(Control obj, AvaloniaPropertyChangedEventArgs change)
+    {
+        if (change.Property != EnableWHAnimationProperty) return;
+        _ = change.NewValue is bool value ? value : throw new ArgumentNullException();
         if (value)
         {
             var triggerProperty = GetTriggerAvaloniaProperty(obj);
@@ -111,7 +129,14 @@ public class SizeAnimationHelper : AvaloniaObject
                     "SizeAnimationHelper does not support Visual.BoundsProperty or Layoutable.DesiredSizeProperty as trigger property.");
             }
 
-            obj.Loaded += ObjOnLoaded;
+            if (obj.IsLoaded)
+            {
+                obj.PropertyChanged += AnimationTargetOnPropertyChanged;
+            }
+            else
+            {
+                obj.Loaded += ObjOnLoaded;
+            }
         }
         else
         {
@@ -126,11 +151,6 @@ public class SizeAnimationHelper : AvaloniaObject
         }
     }
 
-    public static bool GetEnableWHAnimation(Control obj)
-    {
-        return obj.GetValue(EnableWHAnimationProperty);
-    }
-
     private static void AnimationTargetOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
     {
         if (sender is not Control control ||

From c631c9a8711f7b7ef89ebd02df58519ed37fa3c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=9B=E5=B0=98=E7=A9=BA=E5=BF=A7?=
 <wckfxxjstdwckyxphdhqxg@outlook.com>
Date: Mon, 18 Aug 2025 23:11:02 +0800
Subject: [PATCH 6/6] feat:Add several predefined SizeAnimations.

---
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml        |   4 +-
 demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs     |  34 ------
 src/Ursa.Themes.Semi/Controls/NavMenu.axaml   |  69 +++++++-----
 src/Ursa.Themes.Semi/Index.axaml.cs           |   4 +-
 .../SizeAnimations/DefaultSizeAnimations.cs   | 105 ++++++++++++++++++
 .../SizeAnimations/NavMenuSizeAnimations.cs   |  52 +++++++++
 6 files changed, 201 insertions(+), 67 deletions(-)
 create mode 100644 src/Ursa.Themes.Semi/SizeAnimations/DefaultSizeAnimations.cs
 create mode 100644 src/Ursa.Themes.Semi/SizeAnimations/NavMenuSizeAnimations.cs

diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
index 906b6e4..52f973e 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml
@@ -41,9 +41,7 @@
                 ItemsSource="{Binding MenuItems}"
                 SelectedItem="{Binding SelectedMenuItem}"
                 SubMenuBinding="{Binding Children}"
-                u:SizeAnimationHelper.TriggerAvaloniaProperty="{x:Static u:NavMenu.IsHorizontalCollapsedProperty}"
-                u:SizeAnimationHelper.CreateAnimation="{x:Static views:NavMenuDemo.NavMenuAnimation}"
-                u:SizeAnimationHelper.EnableWHAnimation="True">
+                Classes="enable_animation">
                 <u:NavMenu.Styles>
                     <Style x:DataType="vm:MenuItem" Selector="u|NavMenuItem">
                         <Setter Property="IsSeparator" Value="{Binding IsSeparator}" />
diff --git a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
index 368187b..4b4b0c9 100644
--- a/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs
@@ -17,38 +17,4 @@ public partial class NavMenuDemo : UserControl
     {
         InitializeComponent();
     }
-
-    public static SizeAnimationHelperAnimationGeneratorDelegate NavMenuAnimation { get; } =
-        (_, oldDesiredSize, newDesiredSize) =>
-        {
-            if (oldDesiredSize.Width > newDesiredSize.Width)
-                newDesiredSize = newDesiredSize.WithWidth(newDesiredSize.Width + 20);
-            return new Animation
-            {
-                Duration = TimeSpan.FromMilliseconds(300),
-                Easing = new CubicEaseInOut(),
-                FillMode = FillMode.None,
-                Children =
-                {
-                    new KeyFrame
-                    {
-                        Cue = new Cue(0.0),
-                        Setters =
-                        {
-                            new Setter(WidthProperty, oldDesiredSize.Width),
-                            new Setter(HeightProperty, oldDesiredSize.Height)
-                        }
-                    },
-                    new KeyFrame
-                    {
-                        Cue = new Cue(1.0),
-                        Setters =
-                        {
-                            new Setter(WidthProperty, newDesiredSize.Width),
-                            new Setter(HeightProperty, newDesiredSize.Height)
-                        }
-                    }
-                }
-            };
-        };
 }
\ No newline at end of file
diff --git a/src/Ursa.Themes.Semi/Controls/NavMenu.axaml b/src/Ursa.Themes.Semi/Controls/NavMenu.axaml
index d92c3ab..accc2af 100644
--- a/src/Ursa.Themes.Semi/Controls/NavMenu.axaml
+++ b/src/Ursa.Themes.Semi/Controls/NavMenu.axaml
@@ -12,27 +12,27 @@
             <ControlTemplate TargetType="u:NavMenu">
                 <Grid RowDefinitions="Auto, *, Auto">
                     <ContentPresenter Content="{TemplateBinding Header}" />
-					<ScrollViewer
-						Grid.Row="1"
-						HorizontalAlignment="Stretch"
-						HorizontalScrollBarVisibility="Disabled"
-						AllowAutoHide="True"
-						VerticalScrollBarVisibility="Auto">
-						<ScrollViewer.Styles>
-							<Style Selector="ScrollViewer /template/ ScrollBar">
-								<Setter Property="Opacity" Value="0" />
-							</Style>
-							<Style Selector="ScrollViewer:pointerover">
-								<Style Selector="^ /template/ ScrollBar#PART_HorizontalScrollBar">
-									<Setter Property="Opacity" Value="1" />
-								</Style>
-								<Style Selector="^ /template/ ScrollBar#PART_VerticalScrollBar">
-									<Setter Property="Opacity" Value="1" />
-								</Style>
-							</Style>
-						</ScrollViewer.Styles>
-						<ItemsPresenter Name="PART_ItemsPresenter" ItemsPanel="{TemplateBinding ItemsPanel}" />
-					</ScrollViewer>
+                    <ScrollViewer
+                        Grid.Row="1"
+                        HorizontalAlignment="Stretch"
+                        HorizontalScrollBarVisibility="Disabled"
+                        AllowAutoHide="True"
+                        VerticalScrollBarVisibility="Auto">
+                        <ScrollViewer.Styles>
+                            <Style Selector="ScrollViewer /template/ ScrollBar">
+                                <Setter Property="Opacity" Value="0" />
+                            </Style>
+                            <Style Selector="ScrollViewer:pointerover">
+                                <Style Selector="^ /template/ ScrollBar#PART_HorizontalScrollBar">
+                                    <Setter Property="Opacity" Value="1" />
+                                </Style>
+                                <Style Selector="^ /template/ ScrollBar#PART_VerticalScrollBar">
+                                    <Setter Property="Opacity" Value="1" />
+                                </Style>
+                            </Style>
+                        </ScrollViewer.Styles>
+                        <ItemsPresenter Name="PART_ItemsPresenter" ItemsPanel="{TemplateBinding ItemsPanel}" />
+                    </ScrollViewer>
                     <ContentPresenter Grid.Row="2" Content="{TemplateBinding Footer}" />
                 </Grid>
             </ControlTemplate>
@@ -44,6 +44,15 @@
             <Setter Property="Width" Value="{Binding $self.CollapseWidth}" />
             <Setter Property="Grid.IsSharedSizeScope" Value="False" />
         </Style>
+        <Style Selector="^.enable_animation">
+            <Setter Property="u:SizeAnimationHelper.TriggerAvaloniaProperty"
+                    Value="{x:Static u:NavMenu.IsHorizontalCollapsedProperty}">
+            </Setter>
+            <Setter Property="u:SizeAnimationHelper.CreateAnimation"
+                    Value="{DynamicResource NavMenuWidthAnimationGenerator}">
+            </Setter>
+            <Setter Property="u:SizeAnimationHelper.EnableWHAnimation" Value="True"></Setter>
+        </Style>
     </ControlTheme>
 
     <ControlTemplate x:Key="DefaultNavMenuItemTemplate" TargetType="u:NavMenuItem">
@@ -134,13 +143,15 @@
                         <Transitions>
                             <DoubleTransition Easing="QuadraticEaseIn" Property="Height" Duration="0.25" />
                             <DoubleTransition Easing="QuadraticEaseOut" Property="Opacity" Duration="0.25" />
-                            <TransformOperationsTransition Easing="QuadraticEaseInOut" Property="RenderTransform" Duration="0.25" />
+                            <TransformOperationsTransition Easing="QuadraticEaseInOut" Property="RenderTransform"
+                                                           Duration="0.25" />
                         </Transitions>
                     </ItemsPresenter.Transitions>
                 </ItemsPresenter>
                 <LayoutTransformControl.Transitions>
                     <Transitions>
-                        <TransformOperationsTransition Easing="QuadraticEaseInOut" Property="LayoutTransform" Duration="0.15" Delay="0.1" />
+                        <TransformOperationsTransition Easing="QuadraticEaseInOut" Property="LayoutTransform"
+                                                       Duration="0.15" Delay="0.1" />
                     </Transitions>
                 </LayoutTransformControl.Transitions>
             </LayoutTransformControl>
@@ -183,12 +194,12 @@
         <Style Selector="^ /template/ ContentPresenter#PART_HeaderPresenter:pointerover">
             <Setter Property="Foreground" Value="{DynamicResource ListBoxItemPointeroverForeground}" />
         </Style>
-		<Style Selector="^:focus /template/ Border#PART_Border">
-			<Setter Property="Background" Value="{DynamicResource ListBoxItemPointeroverBackground}" />
-		</Style>
-		<Style Selector="^:focus /template/ ContentPresenter#PART_HeaderPresenter">
-			<Setter Property="Foreground" Value="{DynamicResource ListBoxItemPointeroverForeground}" />
-		</Style>
+        <Style Selector="^:focus /template/ Border#PART_Border">
+            <Setter Property="Background" Value="{DynamicResource ListBoxItemPointeroverBackground}" />
+        </Style>
+        <Style Selector="^:focus /template/ ContentPresenter#PART_HeaderPresenter">
+            <Setter Property="Foreground" Value="{DynamicResource ListBoxItemPointeroverForeground}" />
+        </Style>
         <Style Selector="^:horizontal-collapsed:first-level">
             <Setter Property="HorizontalAlignment" Value="Stretch" />
             <Style Selector="^ /template/ Border#PART_Border">
diff --git a/src/Ursa.Themes.Semi/Index.axaml.cs b/src/Ursa.Themes.Semi/Index.axaml.cs
index aad0df8..1d77618 100644
--- a/src/Ursa.Themes.Semi/Index.axaml.cs
+++ b/src/Ursa.Themes.Semi/Index.axaml.cs
@@ -26,6 +26,8 @@ public class SemiTheme : Styles
     public SemiTheme(IServiceProvider? provider = null)
     {
         AvaloniaXamlLoader.Load(provider, this);
+        Resources.MergedDictionaries.Add(new SizeAnimations.DefaultSizeAnimations());
+        Resources.MergedDictionaries.Add(new SizeAnimations.NavMenuSizeAnimations());
     }
 
     public static ThemeVariant Aquatic => new(nameof(Aquatic), ThemeVariant.Dark);
@@ -95,4 +97,4 @@ public class SemiTheme : Styles
         if (!_localeToResource.TryGetValue(culture, out var resources)) return;
         foreach (var kv in resources) element.Resources[kv.Key] = kv.Value;
     }
-}
+}
\ No newline at end of file
diff --git a/src/Ursa.Themes.Semi/SizeAnimations/DefaultSizeAnimations.cs b/src/Ursa.Themes.Semi/SizeAnimations/DefaultSizeAnimations.cs
new file mode 100644
index 0000000..2172c0c
--- /dev/null
+++ b/src/Ursa.Themes.Semi/SizeAnimations/DefaultSizeAnimations.cs
@@ -0,0 +1,105 @@
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.Styling;
+using Ursa.Helpers;
+
+namespace Ursa.Themes.Semi.SizeAnimations;
+
+public partial class DefaultSizeAnimations : ResourceDictionary
+{
+    public const string WidthAnimationGeneratorKey = "WidthAnimationGenerator";
+    public const string HeightAnimationGeneratorKey = "HeightAnimationGenerator";
+    public const string WidthHeightAnimationGeneratorKey = "WidthHeightAnimationGenerator";
+
+    public DefaultSizeAnimations()
+    {
+        Add(WidthAnimationGeneratorKey, WidthAnimationGenerator);
+        Add(HeightAnimationGeneratorKey, HeightAnimationGenerator);
+        Add(WidthHeightAnimationGeneratorKey, WidthHeightAnimationGenerator);
+    }
+
+    private readonly SizeAnimationHelperAnimationGeneratorDelegate WidthAnimationGenerator =
+        (_, oldDesiredSize, newDesiredSize) => new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(300),
+            Easing = new CubicEaseInOut(),
+            FillMode = FillMode.None,
+            Children =
+            {
+                new KeyFrame
+                {
+                    Cue = new Cue(0.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, oldDesiredSize.Width)
+                    }
+                },
+                new KeyFrame
+                {
+                    Cue = new Cue(1.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, newDesiredSize.Width)
+                    }
+                }
+            }
+        };
+
+    private readonly SizeAnimationHelperAnimationGeneratorDelegate HeightAnimationGenerator =
+        (_, oldDesiredSize, newDesiredSize) => new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(300),
+            Easing = new CubicEaseInOut(),
+            FillMode = FillMode.None,
+            Children =
+            {
+                new KeyFrame
+                {
+                    Cue = new Cue(0.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.HeightProperty, oldDesiredSize.Height)
+                    }
+                },
+                new KeyFrame
+                {
+                    Cue = new Cue(1.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.HeightProperty, newDesiredSize.Height)
+                    }
+                }
+            }
+        };
+
+    private readonly SizeAnimationHelperAnimationGeneratorDelegate WidthHeightAnimationGenerator =
+        (_, oldDesiredSize, newDesiredSize) => new Animation
+        {
+            Duration = TimeSpan.FromMilliseconds(300),
+            Easing = new CubicEaseInOut(),
+            FillMode = FillMode.None,
+            Children =
+            {
+                new KeyFrame
+                {
+                    Cue = new Cue(0.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, oldDesiredSize.Width),
+                        new Setter(Layoutable.HeightProperty, oldDesiredSize.Height)
+                    }
+                },
+                new KeyFrame
+                {
+                    Cue = new Cue(1.0),
+                    Setters =
+                    {
+                        new Setter(Layoutable.WidthProperty, newDesiredSize.Width),
+                        new Setter(Layoutable.HeightProperty, newDesiredSize.Height)
+                    }
+                }
+            }
+        };
+}
\ No newline at end of file
diff --git a/src/Ursa.Themes.Semi/SizeAnimations/NavMenuSizeAnimations.cs b/src/Ursa.Themes.Semi/SizeAnimations/NavMenuSizeAnimations.cs
new file mode 100644
index 0000000..8e06e87
--- /dev/null
+++ b/src/Ursa.Themes.Semi/SizeAnimations/NavMenuSizeAnimations.cs
@@ -0,0 +1,52 @@
+using Avalonia.Animation;
+using Avalonia.Animation.Easings;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.Styling;
+using Ursa.Helpers;
+
+namespace Ursa.Themes.Semi.SizeAnimations;
+
+public class NavMenuSizeAnimations : ResourceDictionary
+{
+    public const string NavMenuWidthAnimationGeneratorKey = "NavMenuWidthAnimationGenerator";
+
+    public NavMenuSizeAnimations()
+    {
+        Add(NavMenuWidthAnimationGeneratorKey, NavMenuWidthAnimationGenerator);
+    }
+
+    private readonly SizeAnimationHelperAnimationGeneratorDelegate NavMenuWidthAnimationGenerator =
+        (_, oldDesiredSize, newDesiredSize) =>
+        {
+            if (oldDesiredSize.Width > newDesiredSize.Width)
+                newDesiredSize = newDesiredSize.WithWidth(newDesiredSize.Width + 20);
+            return new Animation
+            {
+                Duration = TimeSpan.FromMilliseconds(300),
+                Easing = new CubicEaseInOut(),
+                FillMode = FillMode.None,
+                Children =
+                {
+                    new KeyFrame
+                    {
+                        Cue = new Cue(0.0),
+                        Setters =
+                        {
+                            new Setter(Layoutable.WidthProperty, oldDesiredSize.Width),
+                            new Setter(Layoutable.HeightProperty, oldDesiredSize.Height)
+                        }
+                    },
+                    new KeyFrame
+                    {
+                        Cue = new Cue(1.0),
+                        Setters =
+                        {
+                            new Setter(Layoutable.WidthProperty, newDesiredSize.Width),
+                            new Setter(Layoutable.HeightProperty, newDesiredSize.Height)
+                        }
+                    }
+                }
+            };
+        };
+}
\ No newline at end of file