feat: maxCount.

demo/Ursa.Demo/Pages/AvatarDemo.axaml

@@ -65,7 +65,7 @@
             <u:Avatar Classes="ExtraLarge" />
         </StackPanel>
         <StackPanel Orientation="Horizontal">
-            <u:AvatarGroup>
+            <u:AvatarGroup MaxCount="3">
                 <u:Avatar Classes="Red" Content="LL" />
                 <u:Avatar Classes="" Content="CX" />
                 <u:Avatar Classes="Amber" Content="RM" />

src/Ursa/Controls/Avatar/AvatarGroup.cs

@@ -10,14 +10,14 @@ public class AvatarGroup : ItemsControl
 
     private static readonly FuncTemplate<Panel?> DefaultPanel = new(() => new AvatarGroupPanel());
 
-    public static readonly StyledProperty<int> MaxCountProperty = AvaloniaProperty.Register<AvatarGroup, int>(
+    public static readonly StyledProperty<int?> MaxCountProperty = AvaloniaProperty.Register<AvatarGroup, int?>(
         nameof(MaxCount));
 
     public static readonly StyledProperty<OverlapFromType> OverlapFromProperty =
         AvaloniaProperty.Register<AvatarGroup, OverlapFromType>(
             nameof(OverlapFrom), defaultValue: OverlapFromType.Start);
 
-    public int MaxCount
+    public int? MaxCount
     {
         get => GetValue(MaxCountProperty);
         set => SetValue(MaxCountProperty, value);

src/Ursa/Controls/Avatar/AvatarGroupPanel.cs

@@ -11,16 +11,19 @@ public class AvatarGroupPanel : Panel
         Size size = new Size();
         availableSize = availableSize.WithWidth(double.PositiveInfinity);
         var children = Children;
-        if (children.Count > 0)
+        if (children.Count <= 0) return size;
+        children[0].Measure(availableSize);
+        Size first = children[0].DesiredSize;
+        var group = this.GetLogicalAncestors().OfType<AvatarGroup>().FirstOrDefault();
+        var count = children.Count;
+        if (group?.MaxCount is not null && group.MaxCount >= 0)
         {
-            children[0].Measure(availableSize);
+            count = group.MaxCount.Value + 1;
-            Size first = children[0].DesiredSize;
-            var width = first.Width + first.Width * (children.Count - 1) * 0.75;
-            size = size.WithWidth(width);
-            size = size.WithHeight(first.Height);
         }
 
-        size = size.WithWidth(size.Width);
+        var width = first.Width + first.Width * (count - 1) * 0.75;
+        size = size.WithWidth(width);
+        size = size.WithHeight(first.Height);
         return size;
     }
 
@@ -28,10 +31,18 @@ public class AvatarGroupPanel : Panel
     {
         Rect rect = new Rect(finalSize);
         double num = 0d;
+        var children = Children;
         var group = this.GetLogicalAncestors().OfType<AvatarGroup>().FirstOrDefault();
         var overlapFrom = group?.OverlapFrom;
-        var children = Children;
+        int? maxCount = null;
-        for (var i = 0; i < children.Count; i++)
+        var count = children.Count;
+        if (group?.MaxCount is not null && group.MaxCount >= 0)
+        {
+            maxCount = group.MaxCount;
+            count = maxCount.Value + 1;
+        }
+
+        for (var i = 0; i < count; i++)
         {
             if (overlapFrom is OverlapFromType.Start)
             {
@@ -49,6 +60,14 @@ public class AvatarGroupPanel : Panel
             children[i].Arrange(rect);
         }
 
+        if (maxCount is not null && children.Count > 0)
+        {
+            if (children[maxCount.Value] is Avatar avatar)
+            {
+                avatar.Content = $"+{children.Count - maxCount}";
+            }
+        }
+
         return finalSize;
     }
 }