fix bounds and justification calculations to prevent clipping

src/Avalonia.Base/Media/TextFormatting/TextLineImpl.cs

@@ -1328,7 +1328,7 @@ namespace Avalonia.Media.TextFormatting
                 }
             }
 
-            var inkBounds = new Rect();
+            Rect? inkBounds = null;
 
             for (var index = 0; index < _textRuns.Length; index++)
             {
@@ -1342,7 +1342,14 @@ namespace Avalonia.Media.TextFormatting
 
                             var runBounds = glyphRun.InkBounds.Translate(new Vector(widthIncludingWhitespace, offsetY));
 
-                            inkBounds = inkBounds.Union(runBounds);
+                            if (inkBounds == null)
+                            {
+                                inkBounds = runBounds;
+                            }
+                            else
+                            {
+                                inkBounds = inkBounds.Value.Union(runBounds);
+                            }
 
                             widthIncludingWhitespace += textRun.Size.Width;
 
@@ -1354,7 +1361,16 @@ namespace Avalonia.Media.TextFormatting
                             //Align the bounds at the common baseline
                             var offsetY = -ascent - drawableTextRun.Baseline;
 
-                            inkBounds = inkBounds.Union(new Rect(new Point(widthIncludingWhitespace, offsetY), drawableTextRun.Size));
+                            var drawableBounds = new Rect(new Point(widthIncludingWhitespace, offsetY), drawableTextRun.Size);
+                            
+                            if (inkBounds == null)
+                            {
+                                inkBounds = drawableBounds;
+                            }
+                            else
+                            {
+                                inkBounds = inkBounds.Value.Union(drawableBounds);
+                            }
 
                             widthIncludingWhitespace += drawableTextRun.Size.Width;
 
@@ -1362,6 +1378,8 @@ namespace Avalonia.Media.TextFormatting
                         }
                 }
             }
+            
+            var finalInkBounds = inkBounds ?? new Rect();
 
             var halfLineGap = lineGap * 0.5;
             var naturalHeight = descent - ascent + lineGap;
@@ -1416,18 +1434,15 @@ namespace Avalonia.Media.TextFormatting
                 }
             }
 
-            var extent = inkBounds.Height;
-            //The height of overhanging pixels at the bottom
-            var overhangAfter = inkBounds.Bottom - height + halfLineGap;
-            //The width of overhanging pixels at the natural alignment point. Positive value means we are inside.
-            var overhangLeading = inkBounds.Left;
-            //The width of overhanging pixels at the end of the natural bounds. Positive value means we are inside.
-            var overhangTrailing = widthIncludingWhitespace - inkBounds.Right;
+            var extent = finalInkBounds.Height;
+            var overhangAfter = finalInkBounds.Bottom - height + halfLineGap;
+            var overhangLeading = finalInkBounds.Left;
+            var overhangTrailing = widthIncludingWhitespace - finalInkBounds.Right;
             var hasOverflowed = width > _paragraphWidth;
 
-            var start = GetParagraphOffsetX(width, widthIncludingWhitespace);
+            var start = GetParagraphOffsetX(width, widthIncludingWhitespace, overhangTrailing);
 
-            _inkBounds = inkBounds.Translate(new Vector(start, 0));
+            _inkBounds = finalInkBounds.Translate(new Vector(start, 0));
 
             _bounds = new Rect(start, 0, widthIncludingWhitespace, height);
 
@@ -1453,9 +1468,10 @@ namespace Avalonia.Media.TextFormatting
         /// </summary>
         /// <param name="width">The line width.</param>
         /// <param name="widthIncludingTrailingWhitespace">The paragraph width including whitespace.</param>
+        /// <param name="trailingOverhang">The trailing overhang.</param>
 
         /// <returns>The paragraph offset.</returns>
-        private double GetParagraphOffsetX(double width, double widthIncludingTrailingWhitespace)
+        private double GetParagraphOffsetX(double width, double widthIncludingTrailingWhitespace, double trailingOverhang)
         {
             if (double.IsPositiveInfinity(_paragraphWidth))
             {
@@ -1501,7 +1517,8 @@ namespace Avalonia.Media.TextFormatting
 
                     return Math.Max(0, start);
                 case TextAlignment.Right:
-                    return Math.Max(0, _paragraphWidth - widthIncludingTrailingWhitespace);
+                    var overhangAdjustment = Math.Min(0, trailingOverhang);
+                    return Math.Max(0, _paragraphWidth - widthIncludingTrailingWhitespace + overhangAdjustment);
                 default:
                     return 0;
             }

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -372,6 +372,11 @@ namespace Avalonia.Controls.Presenters
 
             var top = 0d;
             var left = 0.0;
+            
+            foreach (var line in TextLayout.TextLines)
+            {
+                left = Math.Max(left, -Math.Min(0, line.OverhangLeading));
+            }
 
             var textHeight = TextLayout.Height;
 
@@ -627,8 +632,16 @@ namespace Avalonia.Controls.Presenters
 
             InvalidateArrange();
 
-            // The textWidth used here is matching that TextBlock uses to measure the text.
-            var textWidth = TextLayout.OverhangLeading + TextLayout.WidthIncludingTrailingWhitespace + TextLayout.OverhangTrailing;
+            var textWidth = TextLayout.WidthIncludingTrailingWhitespace;
+            
+            foreach (var line in TextLayout.TextLines)
+            {
+                var lineInkWidth = line.WidthIncludingTrailingWhitespace 
+                    - Math.Min(0, line.OverhangLeading) 
+                    - Math.Min(0, line.OverhangTrailing);
+                textWidth = Math.Max(textWidth, lineInkWidth);
+            }
+            
             return new Size(textWidth, TextLayout.Height);
         }
 
@@ -636,7 +649,15 @@ namespace Avalonia.Controls.Presenters
         {
             var finalWidth = finalSize.Width;
 
-            var textWidth = TextLayout.OverhangLeading + TextLayout.WidthIncludingTrailingWhitespace + TextLayout.OverhangTrailing;
+            var textWidth = TextLayout.WidthIncludingTrailingWhitespace;
+            
+            foreach (var line in TextLayout.TextLines)
+            {
+                var lineInkWidth = line.WidthIncludingTrailingWhitespace 
+                    - Math.Min(0, line.OverhangLeading) 
+                    - Math.Min(0, line.OverhangTrailing);
+                textWidth = Math.Max(textWidth, lineInkWidth);
+            }
             textWidth = Math.Ceiling(textWidth);
 
             if (finalSize.Width < textWidth)

src/Avalonia.Controls/TextBlock.cs

@@ -630,7 +630,13 @@ namespace Avalonia.Controls
 
         protected virtual void RenderTextLayout(DrawingContext context, Point origin)
         {
-            TextLayout.Draw(context, origin);
+            var maxLeadingOverhang = 0.0;
+            foreach (var line in TextLayout.TextLines)
+            {
+                maxLeadingOverhang = Math.Max(maxLeadingOverhang, -Math.Min(0, line.OverhangLeading));
+            }
+            
+            TextLayout.Draw(context, new Point(origin.X + maxLeadingOverhang, origin.Y));
         }
 
         private bool _clearTextInternal;
@@ -748,8 +754,17 @@ namespace Avalonia.Controls
             //This implicitly recreated the TextLayout with a new constraint if we previously reset it.
             var textLayout = TextLayout;
 
-            // The textWidth used here is matching that TextPresenter uses to measure the text.
-            return new Size(textLayout.WidthIncludingTrailingWhitespace, textLayout.Height).Inflate(padding);
+            var totalWidth = textLayout.WidthIncludingTrailingWhitespace;
+            
+            foreach (var line in textLayout.TextLines)
+            {
+                var lineInkWidth = line.WidthIncludingTrailingWhitespace 
+                    - Math.Min(0, line.OverhangLeading) 
+                    - Math.Min(0, line.OverhangTrailing);
+                totalWidth = Math.Max(totalWidth, lineInkWidth);
+            }
+            
+            return new Size(totalWidth, textLayout.Height).Inflate(padding);
         }
 
         protected override Size ArrangeOverride(Size finalSize)

src/Skia/Avalonia.Skia/GlyphRunImpl.cs

@@ -64,26 +64,36 @@ namespace Avalonia.Skia
             // "F" text with Inter size 14 has a 0px left bound with SubpixelAntialias but 1px with Antialias.
             using var font = CreateFont(SKFontEdging.SubpixelAntialias);
 
-            var runBounds = new Rect();
             var glyphBounds = ArrayPool<SKRect>.Shared.Rent(count);
 
             font.GetGlyphWidths(_glyphIndices, null, glyphBounds.AsSpan(0, count));
 
             currentX = 0;
+            
+            Rect? runBounds = null;
 
             for (var i = 0; i < count; i++)
             {
                 var gBounds = glyphBounds[i];
                 var advance = glyphInfos[i].GlyphAdvance;
 
-                runBounds = runBounds.Union(new Rect(currentX + gBounds.Left, gBounds.Top, gBounds.Width, gBounds.Height));
+                var glyphRect = new Rect(currentX + gBounds.Left, gBounds.Top, gBounds.Width, gBounds.Height);
+                
+                if (runBounds == null)
+                {
+                    runBounds = glyphRect;
+                }
+                else
+                {
+                    runBounds = runBounds.Value.Union(glyphRect);
+                }
 
                 currentX += advance;
             }
             ArrayPool<SKRect>.Shared.Return(glyphBounds);
 
             BaselineOrigin = baselineOrigin;
-            Bounds = runBounds.Translate(new Vector(baselineOrigin.X, baselineOrigin.Y));
+            Bounds = (runBounds ?? new Rect()).Translate(new Vector(baselineOrigin.X, baselineOrigin.Y));
         }
 
         public double FontRenderingEmSize { get; }