feat: fix various badge layout issues.

demo/Ursa.Demo/Pages/BadgeDemo.axaml

@@ -5,6 +5,9 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:u="https://irihi.tech/ursa"
+    xmlns:viewModels="clr-namespace:Ursa.Demo.ViewModels"
+    xmlns:common="clr-namespace:Ursa.Common;assembly=Ursa"
+    x:DataType="viewModels:BadgeDemoViewModel"
     d:DesignHeight="850"
     d:DesignWidth="850"
     mc:Ignorable="d">
@@ -19,6 +22,15 @@
                     <Setter Property="Margin" Value="10" />
                 </Style>
             </StackPanel.Styles>
+            
+            <Border Theme="{DynamicResource CardBorder}">
+                <StackPanel>
+                    <u:EnumSelector Name="position" EnumType="{x:Type common:CornerPosition}"/>
+                    <u:Badge CornerPosition="{Binding #position.Value}" Header="{Binding Text}">
+                        <Button Content="Test" Command="{Binding ChangeTextCommand}"/>
+                    </u:Badge>
+                </StackPanel>
+            </Border>
 
             <StackPanel Orientation="Horizontal">
                 <u:Badge Header="5">

demo/Ursa.Demo/Pages/BadgeDemo.axaml.cs

@@ -9,9 +9,4 @@ public partial class BadgeDemo : UserControl
     {
         InitializeComponent();
     }
-
-    private void InitializeComponent()
-    {
-        AvaloniaXamlLoader.Load(this);
-    }
 }

demo/Ursa.Demo/ViewModels/BadgeDemoViewModel.cs

@@ -1,6 +1,28 @@
+using System;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
 namespace Ursa.Demo.ViewModels;
 
-public class BadgeDemoViewModel: ViewModelBase
+public partial class BadgeDemoViewModel: ViewModelBase
 {
-    
+    [ObservableProperty] private string? _text = null;
+
+    public BadgeDemoViewModel()
+    {
+        
+    }
+
+    [RelayCommand]
+    public void ChangeText()
+    {
+        if (Text == null)
+        {
+            Text = DateTime.Now.ToShortDateString();
+        }
+        else
+        {
+            Text = null;
+        }
+    }
 }

src/Ursa/Controls/Badge/Badge.cs

@@ -66,6 +66,7 @@ public class Badge : HeaderedContentControl
     static Badge()
     {
         HeaderProperty.Changed.AddClassHandler<Badge>((badge, _) => badge.UpdateBadgePosition());
+        CornerPositionProperty.Changed.AddClassHandler<Badge>((badge, _) => badge.UpdateBadgePosition());
         DotProperty.Changed.AddClassHandler<Badge>((badge, _) => badge.UpdateBadgePosition());
     }
 
@@ -83,8 +84,9 @@ public class Badge : HeaderedContentControl
 
     protected override Size ArrangeOverride(Size finalSize)
     {
+        var size = base.ArrangeOverride(finalSize);
         UpdateBadgePosition();
-        return base.ArrangeOverride(finalSize);
+        return size;
     }
 
     private void UpdateBadgePosition()