Fix TextLayout.OverhandLeading calculation (#13287)

* Fix overhand leading calculation

* Fix test on Mac

* Fix tests

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

@@ -1328,7 +1328,9 @@ namespace Avalonia.Media.TextFormatting
             }
 
             var start = GetParagraphOffsetX(width, widthIncludingWhitespace);
-            var overhangLeading = Math.Max(0, bounds.Left - start);
+            //The width of overhanging pixels at the origin
+            var overhangLeading = Math.Max(0, start - bounds.Left);
+            //The width of overhanging pixels at the end
             var overhangTrailing = Math.Max(0, bounds.Width - widthIncludingWhitespace);
             var hasOverflowed = width > _paragraphWidth;
 

src/Skia/Avalonia.Skia/GlyphRunImpl.cs

@@ -70,11 +70,6 @@ namespace Avalonia.Skia
                 var gBounds = glyphBounds[i];
                 var advance = glyphInfos[i].GlyphAdvance;
 
-                if(gBounds.Width == 0)
-                {
-                    gBounds = new SKRect(0, 0, (float)advance, 1);
-                }
-
                 runBounds = runBounds.Union(new Rect(currentX + gBounds.Left, baselineOrigin.Y + gBounds.Top, gBounds.Width, gBounds.Height));
 
                 currentX += advance;

tests/Avalonia.Skia.UnitTests/Media/GlyphRunTests.cs

@@ -176,18 +176,18 @@ namespace Avalonia.Skia.UnitTests.Media
         }
 
         [Fact]
-        public void GlyphRun_With_Leading_Space_Has_Correct_InBounds()
+        public void GlyphRun_With_Leading_Space_Has_Correct_InkBounds()
         {
             using (Start())
             {
                 var typeface = new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Inter");
                 var options = new TextShaperOptions(typeface.GlyphTypeface, 14);
-                var shapedBuffer = TextShaper.Current.ShapeText(" ", options);
+                var shapedBuffer = TextShaper.Current.ShapeText(" I", options);
 
                 var glyphRun1 = CreateGlyphRun(shapedBuffer);
                 var bounds = glyphRun1.InkBounds;
 
-                Assert.Equal(shapedBuffer[0].GlyphAdvance, bounds.Width);
+                Assert.True(bounds.Left > 0);
             }
         }
 

tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLineTests.cs

@@ -1259,6 +1259,29 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
             }
         }
 
+       
+
+        [Fact]
+        public void Should_GetPreviousCharacterHit_Non_Trailing()
+        {
+            var text = "123.45.67.•";
+
+            using (Start())
+            {
+                var defaultProperties = new GenericTextRunProperties(Typeface.Default);
+                var textSource = new SingleBufferTextSource(text, defaultProperties, true);
+
+                var formatter = new TextFormatterImpl();
+
+                var textLine =
+                    formatter.FormatLine(textSource, 0, double.PositiveInfinity,
+                        new GenericTextParagraphProperties(FlowDirection.LeftToRight, TextAlignment.Left,
+                        true, true, defaultProperties, TextWrapping.NoWrap, 0, 0, 0));
+
+                var characterHit = textLine.GetPreviousCaretCharacterHit(new CharacterHit(10, 1));
+            }
+        }
+
         private class FixedRunsTextSource : ITextSource
         {
             private readonly IReadOnlyList<TextRun> _textRuns;