From b9ff1b23c3e09acb9161116907cb37a4756e19e9 Mon Sep 17 00:00:00 2001
From: Benedikt Schroeder <benedikt.schroeder@outlook.de>
Date: Fri, 9 Oct 2020 18:39:09 +0200
Subject: [PATCH] Make sure we don't crash when RTL text is wrapped

---
 .../Media/TextFormatting/TextFormatterImpl.cs          | 10 +++++++++-
 src/Skia/Avalonia.Skia/TextShaperImpl.cs               |  3 ++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs b/src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs
index 4a7282af27..394dae8253 100644
--- a/src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs
+++ b/src/Avalonia.Visuals/Media/TextFormatting/TextFormatterImpl.cs
@@ -126,7 +126,15 @@ namespace Avalonia.Media.TextFormatting
 
             var lastCluster = glyphRun.GlyphClusters[glyphCount];
 
-            count = lastCluster - firstCluster;
+            if (glyphRun.IsLeftToRight)
+            {
+                count = lastCluster - firstCluster;
+            }
+            else
+            {
+                count = firstCluster - lastCluster;
+            }
+           
 
             return count > 0;
         }
diff --git a/src/Skia/Avalonia.Skia/TextShaperImpl.cs b/src/Skia/Avalonia.Skia/TextShaperImpl.cs
index 61075171fe..31724bfee9 100644
--- a/src/Skia/Avalonia.Skia/TextShaperImpl.cs
+++ b/src/Skia/Avalonia.Skia/TextShaperImpl.cs
@@ -64,7 +64,8 @@ namespace Avalonia.Skia
                     new ReadOnlySlice<double>(glyphAdvances),
                     new ReadOnlySlice<Vector>(glyphOffsets),
                     text,
-                    new ReadOnlySlice<ushort>(clusters));
+                    new ReadOnlySlice<ushort>(clusters),
+                    buffer.Direction == Direction.LeftToRight ? 0 : 1);
             }
         }