fix(wasm): Invalidate TextBlock measure cache when a font successfull…

…y loaded

src/Uno.UI/UI/Xaml/Controls/TextBlock/TextBlock.wasm.cs

@@ -17,7 +17,6 @@ partial class TextBlock : FrameworkElement
 	{
 		private const int MaxMeasureCache = 50;
 
-		private static TextBlockMeasureCache _cache = new TextBlockMeasureCache();
 		private bool _fontStyleChanged;
 		private bool _fontWeightChanged;
 		private bool _textChanged;
@@ -102,7 +101,7 @@ protected override Size MeasureOverride(Size availableSize)
 
 			if (UseInlinesFastPath)
 			{
-				if (_cache.FindMeasuredSize(this, availableSize) is Size desiredSize)
+				if (TextBlockMeasureCache.Instance.FindMeasuredSize(this, availableSize) is Size desiredSize)
 				{
 					UnoMetrics.TextBlock.MeasureCacheHits++;
 					return desiredSize;
@@ -112,7 +111,7 @@ protected override Size MeasureOverride(Size availableSize)
 					UnoMetrics.TextBlock.MeasureCacheMisses++;
 					desiredSize = MeasureView(availableSize);
 
-					_cache.CacheMeasure(this, availableSize, desiredSize);
+					TextBlockMeasureCache.Instance.CacheMeasure(this, availableSize, desiredSize);
 
 					return desiredSize;
 				}

src/Uno.UI/UI/Xaml/Controls/TextBlock/TextBlockMeasureCache.MeasureEntry.cs

@@ -3,6 +3,7 @@
 using Windows.Foundation;
 using Uno;
 using CachedSize = Uno.CachedTuple<double, double>;
+using Windows.UI.Xaml.Media;
 
 namespace Windows.UI.Xaml.Controls
 {

src/Uno.UI/UI/Xaml/Controls/TextBlock/TextBlockMeasureCache.MeasureKey.cs

@@ -89,6 +89,8 @@ public override bool Equals(object obj)
 			private readonly int _characterSpacing;
 			private readonly TextDecorations _textDecorations;
 
+			public FontFamily FontFamily => _fontFamily;
+
 			internal bool IsWrapping => _textWrapping != TextWrapping.NoWrap;
 			internal bool IsClipping => _textTrimming != TextTrimming.None;
 		}

src/Uno.UI/UI/Xaml/Controls/TextBlock/TextBlockMeasureCache.cs

@@ -8,6 +8,7 @@
 using Uno.Extensions;
 using Uno.UI;
 using Uno.Foundation.Logging;
+using Windows.UI.Xaml.Media;
 
 namespace Windows.UI.Xaml.Controls
 {
@@ -23,6 +24,8 @@ internal partial class TextBlockMeasureCache
 
 		private readonly Dictionary<MeasureKey, MeasureEntry> _entries = new Dictionary<MeasureKey, MeasureEntry>(new MeasureKey.Comparer());
 		private readonly LinkedList<MeasureKey> _queue = new LinkedList<MeasureKey>();
+
+		public static readonly TextBlockMeasureCache Instance = new TextBlockMeasureCache();
 
 		/// <summary>
 		/// Finds a cached measure for the provided <see cref="TextBlock"/> characteristics
@@ -98,6 +101,29 @@ public void CacheMeasure(TextBlock source, Size availableSize, Size measuredSize
 			entry.CacheMeasure(availableSize, measuredSize);
 		}
 
+		/// <summary>
+		/// 
+		/// </summary>
+		/// <param name="fontFamily"></param>
+		internal void Clear(FontFamily fontFamily)
+		{
+			List<MeasureKey> keysToRemove = new();
+
+			foreach(var item in _queue)
+			{
+				if (item.FontFamily.CssFontName == fontFamily.CssFontName)
+				{
+					keysToRemove.Add(item);
+				}
+			}
+
+			foreach(var keyToRemove in keysToRemove)
+			{
+				_queue.Remove(keyToRemove);
+				_entries.Remove(keyToRemove);
+			}
+		}
+
 		private void Scavenge()
 		{
 			while (_queue.Count >= MaxMeasureKeyEntries)

src/Uno.UI/UI/Xaml/FontFamilyLoader.wasm.cs

@@ -72,6 +72,8 @@ internal static void NotifyFontLoaded(string cssFontName)
 
 			if (loader._waitingList is { Count: > 0 })
 			{
+				Controls.TextBlockMeasureCache.Instance.Clear(loader._fontFamily);
+
 				foreach (var waiting in loader._waitingList)
 				{
 					if (waiting.IsAlive && waiting.Target is UIElement ue)