Added two GetAndSetRadii methods.

Added documentaiton.

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -365,15 +365,7 @@ namespace Avalonia.Skia
             SKRoundRect skRoundRect = null;
             if (needRoundRect)
             {
-                skRoundRect = SKRoundRectCache.Shared.Get();
+                skRoundRect = SKRoundRectCache.Shared.GetAndSetRadii(rc, rect);
-                skRoundRect.SetRectRadii(rc,
-                    new[]
-                    {
-                        rect.RadiiTopLeft.ToSKPoint(),
-                        rect.RadiiTopRight.ToSKPoint(),
-                        rect.RadiiBottomRight.ToSKPoint(),
-                        rect.RadiiBottomLeft.ToSKPoint(),
-                    });
             }
 
             foreach (var boxShadow in boxShadows)
@@ -389,8 +381,7 @@ namespace Avalonia.Skia
                         Canvas.Save();
                         if (isRounded)
                         {
-                            var shadowRect = SKRoundRectCache.Shared.Get();
+                            var shadowRect = SKRoundRectCache.Shared.GetAndSetRadii(skRoundRect!.Rect, skRoundRect.Radii);
-                            shadowRect.SetRectRadii(skRoundRect!.Rect, skRoundRect.Radii);
                             if (spread != 0)
                                 shadowRect.Inflate(spread, spread);
                             Canvas.ClipRoundRect(skRoundRect,
@@ -446,8 +437,7 @@ namespace Avalonia.Skia
                         var outerRect = AreaCastingShadowInHole(rc, (float)boxShadow.Blur, spread, offsetX, offsetY);
 
                         Canvas.Save();
-                        var shadowRect = SKRoundRectCache.Shared.Get();
+                        var shadowRect = SKRoundRectCache.Shared.GetAndSetRadii(skRoundRect!.Rect, skRoundRect.Radii);
-                        shadowRect.SetRectRadii(skRoundRect!.Rect, skRoundRect.Radii);
                         if (spread != 0)
                             shadowRect.Deflate(spread, spread);
                         Canvas.ClipRoundRect(skRoundRect,

src/Skia/Avalonia.Skia/SKRoundRectCache.cs

@@ -1,13 +1,73 @@
-using System.Collections.Concurrent;
+using System.Buffers;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
 using SkiaSharp;
 
 namespace Avalonia.Skia
 {
     /// <summary>
-    /// Cache for SKPaints.
+    /// Cache for SKRoundRectCache.
     /// </summary>
     internal class SKRoundRectCache : SKCacheBase<SKRoundRect, SKRoundRectCache>
     {
+        /// <summary>
+        /// Cache for points to use for setting the radii.
+        /// </summary>
+        private readonly ConcurrentBag<SKPoint[]> _radiiCache = new();
+
+        /// <summary>
+        /// Gets a cached SKRoundRect and sets it with the passed rectangle and Radii.
+        /// </summary>
+        /// <param name="rectangle">Rectangle size to set the cached rectangle to.</param>
+        /// <param name="roundedRect">Rounded rectangle to copy the radii from.</param>
+        /// <returns>Configured rounded rectangle</returns>
+        public SKRoundRect GetAndSetRadii(in SKRect rectangle, in RoundedRect roundedRect)
+        {
+            if (!Cache.TryTake(out var item))
+            {
+                item = new SKRoundRect();
+            }
+            
+            // Try and acquire a cached point array.
+            if (!_radiiCache.TryTake(out var skArray))
+            {
+                skArray = new SKPoint[4];
+            }
+
+            skArray[0].X = (float)roundedRect.RadiiTopLeft.X;
+            skArray[0].Y = (float)roundedRect.RadiiTopLeft.Y;
+            skArray[1].X = (float)roundedRect.RadiiTopRight.X;
+            skArray[1].Y = (float)roundedRect.RadiiTopRight.Y;
+            skArray[2].X = (float)roundedRect.RadiiBottomRight.X;
+            skArray[2].Y = (float)roundedRect.RadiiBottomRight.Y;
+            skArray[3].X = (float)roundedRect.RadiiBottomLeft.X;
+            skArray[3].Y = (float)roundedRect.RadiiBottomLeft.Y;
+
+            item.SetRectRadii(rectangle, skArray);
+
+            // Add the array back to the cache.
+            _radiiCache.Add(skArray);
+
+            return item;
+        }
+
+        /// <summary>
+        /// Gets a cached SKRoundRect and sets it with the passed rectangle and Radii.
+        /// </summary>
+        /// <param name="rectangle">Rectangle size to set the cached rectangle to.</param>
+        /// <param name="radii">point array of radii.</param>
+        /// <returns>Configured rounded rectangle</returns>
+        public SKRoundRect GetAndSetRadii(in SKRect rectangle, in SKPoint[] radii)
+        {
+            if (!Cache.TryTake(out var item))
+            {
+                item = new SKRoundRect();
+            }
+
+            item.SetRectRadii(rectangle, radii);
+
+            return item;
+        }
         /// <summary>
         /// Returns a SKPaint and resets it for reuse later.
         /// </summary>
@@ -22,5 +82,17 @@ namespace Avalonia.Skia
             rect.SetEmpty();
             Cache.Add(rect);
         }
+
+        /// <summary>
+        /// Clears and disposes all cached items.
+        /// </summary>
+        public new void Clear()
+        {
+            base.Clear();
+
+            // Clear out the cache of SKPoint arrays.
+            _radiiCache.Clear();
+        }
+
     }
 }