From 6727bbe3dfeadf97af3a9c771553a4c7e3007d4b Mon Sep 17 00:00:00 2001
From: Dariusz Komosinski <darek.komosinski@gmail.com>
Date: Tue, 5 Mar 2019 18:26:53 +0100
Subject: [PATCH] Fix Skia rendering hairline width strokes when Pen thickness
 is 0.

---
 src/Skia/Avalonia.Skia/DrawingContextImpl.cs  |   8 ++++++-
 .../Shapes/RectangleTests.cs                  |  20 ++++++++++++++++++
 .../Rectangle_0px_Stroke.expected.png         | Bin 0 -> 610 bytes
 .../Rectangle_0px_Stroke.expected.png         | Bin 0 -> 610 bytes
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 tests/TestFiles/Direct2D1/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png
 create mode 100644 tests/TestFiles/Skia/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png

diff --git a/src/Skia/Avalonia.Skia/DrawingContextImpl.cs b/src/Skia/Avalonia.Skia/DrawingContextImpl.cs
index 353354da5e..10e746cbd5 100644
--- a/src/Skia/Avalonia.Skia/DrawingContextImpl.cs
+++ b/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;
 
diff --git a/tests/Avalonia.RenderTests/Shapes/RectangleTests.cs b/tests/Avalonia.RenderTests/Shapes/RectangleTests.cs
index d48765a360..6d4a840641 100644
--- a/tests/Avalonia.RenderTests/Shapes/RectangleTests.cs
+++ b/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()
         {
diff --git a/tests/TestFiles/Direct2D1/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png b/tests/TestFiles/Direct2D1/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..27aacea049120e0237d04b64879b49dcd2c345db
GIT binary patch
literal 610
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zhE&A8J+YCufkA-T@LT*ZL9gnZ2Zws+?`Ez`VVcb8qh>Jkz$jxV2EvD(&skS_v(4Lj
TKJ5oEJurB>`njxgN@xNA1oFn1

literal 0
HcmV?d00001

diff --git a/tests/TestFiles/Skia/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png b/tests/TestFiles/Skia/Shapes/Rectangle/Rectangle_0px_Stroke.expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..27aacea049120e0237d04b64879b49dcd2c345db
GIT binary patch
literal 610
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zhE&A8J+YCufkA-T@LT*ZL9gnZ2Zws+?`Ez`VVcb8qh>Jkz$jxV2EvD(&skS_v(4Lj
TKJ5oEJurB>`njxgN@xNA1oFn1

literal 0
HcmV?d00001