Merge remote-tracking branch 'origin/release/6.0' into release/6.0

controlgallery/AtomUIGallery/ShowCases/DataDisplay/DateViewer/Views/DateViewerShowCase.axaml

@@ -47,7 +47,7 @@
             <gallery:ShowCasePanel Name="ExamplesContent"
                                    IsScrollEnabled="False"
                                    IsDeferredLoadingEnabled="True"
-                                   InitialDeferredLoadItemCount="4"
+                                   InitialDeferredLoadItemCount="1"
                                    DeferredLoadBatchSize="2"
                                    MaxColumns="1"
                                    ContentMargin="28,10,28,28">

docs/modules/toolkits-gallery-base/showcase-controls.md

@@ -143,6 +143,7 @@ public class ShowCasePanel : TemplatedControl
 - 新挂载、恢复可见或不再占满整行的 item 在首次重新进入普通布局时放入当前最短列。
 - 有效列数变化时清除旧列假设，并按当前最短列重新建立全部归属。
 - `ShowCaseItemSpan.Full` 或 `IsOccupyEntireRow=true` 占满整行，不进入普通列归属。
+- 测量与实际排列宽度不同时，按排列宽度重新测量子项，并在输入测量宽度不变的后续布局中沿用该宽度，避免分数缩放下重复失效；输入宽度变化或脱离视觉树时清除该记录。
 - 不做虚拟化，只负责已挂载 children 的测量和排列。
 
 该面板保持简单，不引入 ItemsControl、ItemsSource 或数据模板。ShowCase 页面是文档式页面，不是无限列表。

src/AtomUI.Toolkits.GalleryBase/Controls/ShowCaseMasonryPanel.cs

@@ -23,6 +23,8 @@ public class ShowCaseMasonryPanel : Panel
     private double _measuredEffectiveWidth;
     private int _measuredChildCount;
     private bool _hasMeasuredLayout;
+    private double _previousAvailableWidth = double.NaN;
+    private double? _arrangedEffectiveWidth;
     private readonly Dictionary<Control, int> _stableColumns = new(ReferenceEqualityComparer.Instance);
     private int _stableColumnCount;
     private bool _hasStableAssignments;
@@ -62,7 +64,16 @@ public class ShowCaseMasonryPanel : Panel
 
     protected override Size MeasureOverride(Size availableSize)
     {
-        var layout = CalculateLayout(availableSize.Width, true);
+        if (_previousAvailableWidth != availableSize.Width)
+        {
+            _arrangedEffectiveWidth = null;
+        }
+        _previousAvailableWidth = availableSize.Width;
+        // Ancestor layout rounding can give us a different final width even when the
+        // measure constraint is unchanged. Reuse that width on the follow-up measure
+        // so arrange-time child measurement does not invalidate us on every pass.
+        var effectiveWidth = _arrangedEffectiveWidth ?? ResolveAvailableWidth(availableSize.Width);
+        var layout = CalculateLayout(effectiveWidth, true);
         _measuredLayout = layout;
         _measuredEffectiveWidth = layout.Width;
         _measuredChildCount = Children.Count;
@@ -74,6 +85,7 @@ public class ShowCaseMasonryPanel : Panel
     protected override Size ArrangeOverride(Size finalSize)
     {
         var effectiveWidth = ResolveAvailableWidth(finalSize.Width);
+        _arrangedEffectiveWidth = effectiveWidth;
         var canReuseMeasuredLayout = _hasMeasuredLayout &&
                                       _measuredChildCount == Children.Count &&
                                       AreClose(_measuredEffectiveWidth, effectiveWidth);
@@ -101,6 +113,8 @@ public class ShowCaseMasonryPanel : Panel
     {
         _hasMeasuredLayout = false;
         _measuredLayout = null;
+        _previousAvailableWidth = double.NaN;
+        _arrangedEffectiveWidth = null;
         ClearStableAssignments();
         base.OnDetachedFromVisualTree(e);
     }