Fix Skia rendering hairline width strokes when Pen thickness is 0.

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -501,7 +501,6 @@ namespace Avalonia.Skia
         {
             var paint = new SKPaint
             {
-                IsStroke = false,
                 IsAntialias = true
             };
 
@@ -558,6 +557,13 @@ namespace Avalonia.Skia
         /// <returns></returns>
         private PaintWrapper CreatePaint(Pen pen, Size targetSize)
         {
+            // In Skia 0 thickness means - use hairline rendering
+            // and for us it means - there is nothing rendered.
+            if (pen.Thickness == 0d)
+            {
+                return default;
+            }
+
             var rv = CreatePaint(pen.Brush, targetSize);
             var paint = rv.Paint;
 

tests/Avalonia.RenderTests/Shapes/RectangleTests.cs

@@ -20,6 +20,26 @@ namespace Avalonia.Direct2D1.RenderTests.Shapes
         {
         }
 
+        [Fact]
+        public async Task Rectangle_0px_Stroke()
+        {
+            Decorator target = new Decorator
+            {
+                Padding = new Thickness(8),
+                Width = 200,
+                Height = 200,
+                Child = new Rectangle
+                {
+                    Fill = Brushes.Transparent,
+                    Stroke = Brushes.Black,
+                    StrokeThickness = 0
+                }
+            };
+
+            await RenderToFile(target);
+            CompareImages();
+        }
+
         [Fact]
         public async Task Rectangle_1px_Stroke()
         {