From e2ec8149e7880f281a13a05598ba3ffc1ecfc8e0 Mon Sep 17 00:00:00 2001
From: Benedikt Stebner <Gillibald@users.noreply.github.com>
Date: Thu, 1 Aug 2024 06:54:04 +0200
Subject: [PATCH] Do not set the baselineOrigin of ShapedTextRuns to (0,0) and
 rework the BaselineOffset calculation (#16545)

Co-authored-by: Jumar Macato <16554748+jmacato@users.noreply.github.com>
---
 .../Media/TextFormatting/ShapedTextRun.cs     |  3 +--
 .../Media/TextFormatting/TextLineImpl.cs      | 23 +++++++++++++------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/Avalonia.Base/Media/TextFormatting/ShapedTextRun.cs b/src/Avalonia.Base/Media/TextFormatting/ShapedTextRun.cs
index f01de9cc9e..05f3f84d45 100644
--- a/src/Avalonia.Base/Media/TextFormatting/ShapedTextRun.cs
+++ b/src/Avalonia.Base/Media/TextFormatting/ShapedTextRun.cs
@@ -204,8 +204,7 @@ namespace Avalonia.Media.TextFormatting
                 ShapedBuffer.FontRenderingEmSize,
                 Text,
                 ShapedBuffer,
-                biDiLevel: BidiLevel,
-                baselineOrigin: new Point());
+                biDiLevel: BidiLevel);
         }
 
         public void Dispose()
diff --git a/src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs b/src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs
index 154c98ae54..c6da172604 100644
--- a/src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs
+++ b/src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs
@@ -96,7 +96,7 @@ namespace Avalonia.Media.TextFormatting
                 {
                     case DrawableTextRun drawableTextRun:
                         {
-                            var offsetY = GetBaselineOffset(this, drawableTextRun);
+                            var offsetY = GetBaselineOffset(drawableTextRun);
 
                             drawableTextRun.Draw(drawingContext, new Point(currentX, currentY + offsetY));
 
@@ -108,29 +108,38 @@ namespace Avalonia.Media.TextFormatting
             }
         }
 
-        private static double GetBaselineOffset(TextLine textLine, DrawableTextRun textRun)
+        private double GetBaselineOffset(DrawableTextRun textRun)
         {
             var baseline = textRun.Baseline;
             var baselineAlignment = textRun.Properties?.BaselineAlignment;
 
+            var baselineOffset = -baseline;
+
             switch (baselineAlignment)
             {
                 case BaselineAlignment.Baseline:
-                    return textLine.Baseline;
+                    baselineOffset += Baseline;
+                    break;
                 case BaselineAlignment.Top:
                 case BaselineAlignment.TextTop:
-                    return textLine.Baseline - textLine.Extent + textRun.Size.Height / 2;
+                    baselineOffset += Height - Extent + textRun.Size.Height / 2;
+                    break;
                 case BaselineAlignment.Center:
-                    return textLine.Height / 2 + baseline - textRun.Size.Height / 2;
+                    baselineOffset += Height / 2 + baseline - textRun.Size.Height / 2;
+                    break;
                 case BaselineAlignment.Subscript:
                 case BaselineAlignment.Bottom:
                 case BaselineAlignment.TextBottom:
-                    return textLine.Height - textRun.Size.Height + baseline;
+                    baselineOffset += Height - textRun.Size.Height + baseline;
+                    break;
                 case BaselineAlignment.Superscript:
-                    return baseline;
+                    baselineOffset += baseline;
+                    break;
                 default:
                     throw new ArgumentOutOfRangeException(nameof(baselineAlignment), baselineAlignment, null);
             }
+
+            return baselineOffset;
         }
 
         /// <inheritdoc/>