From 9c3bfd2e92623bc475efc2fb261169d438e76e6e Mon Sep 17 00:00:00 2001
From: Benedikt Stebner <b.stebner@outlook.de>
Date: Wed, 5 May 2021 17:04:52 +0200
Subject: [PATCH 1/2] Add failing test

---
 .../Media/TextFormatting/TextShaperTests.cs   | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextShaperTests.cs

diff --git a/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextShaperTests.cs b/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextShaperTests.cs
new file mode 100644
index 0000000000..62d2c54ffe
--- /dev/null
+++ b/tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextShaperTests.cs
@@ -0,0 +1,43 @@
+using System;
+using System.Globalization;
+using Avalonia.Media;
+using Avalonia.Media.TextFormatting;
+using Avalonia.UnitTests;
+using Xunit;
+
+namespace Avalonia.Skia.UnitTests.Media.TextFormatting
+{
+    public class TextShaperTests
+    {
+        [Fact]
+        public void Should_Form_Clusters_For_BreakPairs()
+        {
+            using (Start())
+            {
+                var text = "\n\r\n".AsMemory();
+
+                var glyphRun = TextShaper.Current.ShapeText(
+                    text,
+                    Typeface.Default,
+                    12,
+                    CultureInfo.CurrentCulture);
+                
+                Assert.Equal(glyphRun.Characters.Length, text.Length);
+                Assert.Equal(glyphRun.GlyphClusters.Length, text.Length);
+                Assert.Equal(0, glyphRun.GlyphClusters[0]);
+                Assert.Equal(1, glyphRun.GlyphClusters[1]);
+                Assert.Equal(1, glyphRun.GlyphClusters[2]);
+            }
+        }
+        
+        private static IDisposable Start()
+        {
+            var disposable = UnitTestApplication.Start(TestServices.MockPlatformRenderInterface
+                .With(renderInterface: new PlatformRenderInterface(null),
+                    textShaperImpl: new TextShaperImpl(),
+                    fontManagerImpl: new CustomFontManagerImpl()));
+
+            return disposable;
+        }
+    }
+}

From a301d0beeb71e59ab20ac42c48794ab04411221a Mon Sep 17 00:00:00 2001
From: Benedikt Stebner <b.stebner@outlook.de>
Date: Wed, 5 May 2021 17:05:54 +0200
Subject: [PATCH 2/2] Fix cluster builder for break pairs

---
 src/Skia/Avalonia.Skia/TextShaperImpl.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Skia/Avalonia.Skia/TextShaperImpl.cs b/src/Skia/Avalonia.Skia/TextShaperImpl.cs
index 31724bfee9..5cf72e2ce8 100644
--- a/src/Skia/Avalonia.Skia/TextShaperImpl.cs
+++ b/src/Skia/Avalonia.Skia/TextShaperImpl.cs
@@ -87,7 +87,7 @@ namespace Avalonia.Skia
                     {
                         var nextCodepoint = Codepoint.ReadAt(text, i + 1, out _);
 
-                        if (nextCodepoint == '\r' && codepoint == '\n' || nextCodepoint == '\n' && codepoint == '\r')
+                        if (nextCodepoint == '\n' && codepoint == '\r')
                         {
                             count++;