Merge branch 'master' into typefaceSeperation

Author: Gillibald

src/Avalonia.Base/Media/FontManager.cs

@@ -163,7 +163,7 @@ public bool TryGetGlyphTypeface(Typeface typeface, [NotNullWhen(true)] out IGlyp
             }
 
             //Nothing was found so use the default
-            return TryGetGlyphTypeface(new Typeface(FontFamily.DefaultFontFamilyName, typeface.Style, typeface.Weight, typeface.Stretch), out glyphTypeface);
+            return TryGetGlyphTypeface(new Typeface(DefaultFontFamily, typeface.Style, typeface.Weight, typeface.Stretch), out glyphTypeface);
 
             FontFamily GetMappedFontFamily(FontFamily fontFamily)
             {
@@ -385,6 +385,12 @@ private string GetDefaultFontFamilyName(FontManagerOptions? options)
                     "Default font family name can't be null or empty.");
             }
 
+            if (defaultFontFamilyName == FontFamily.DefaultFontFamilyName)
+            {
+                throw new InvalidOperationException(
+                    $"'{FontFamily.DefaultFontFamilyName}' is a placeholder and cannot be used as the default font family name. Provide a concrete font family name via {nameof(FontManagerOptions)} or the platform implementation.");
+            }
+
             return defaultFontFamilyName;
         }
 

src/Avalonia.Base/Media/GlyphRun.cs

@@ -711,9 +711,13 @@ private GlyphRunMetrics CreateGlyphRunMetrics()
                 }
             }
 
+            var ascent = GlyphTypeface.Metrics.Ascent * Scale;
+            var lineGap = GlyphTypeface.Metrics.LineGap * Scale;
+            var baseline = -ascent + lineGap * 0.5;
+
             return new GlyphRunMetrics
             {
-                Baseline = -GlyphTypeface.Metrics.Ascent * Scale,
+                Baseline = baseline,
                 Width = width,
                 WidthIncludingTrailingWhitespace = widthIncludingTrailingWhitespace,
                 Height = height,

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

@@ -36,7 +36,7 @@ public override int Length
 
         public TextMetrics TextMetrics { get; }
 
-        public override double Baseline => -TextMetrics.Ascent;
+        public override double Baseline => -TextMetrics.Ascent + TextMetrics.LineGap * 0.5;
 
         public override Size Size => GlyphRun.Bounds.Size;
 

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

@@ -814,7 +814,7 @@ bool TryMergeWithLastBounds(TextBounds currentBounds, TextBounds lastBounds)
             }
         }
 
-        private CharacterHit GetPreviousCharacterHit(CharacterHit characterHit, bool useGraphemeBoundaries)
+        private CharacterHit GetPreviousCharacterHit(CharacterHit characterHit, bool isBackspaceDelete)
         {
             if (_textRuns.Length == 0 || _indexedTextRuns is null)
             {
@@ -833,8 +833,6 @@ private CharacterHit GetPreviousCharacterHit(CharacterHit characterHit, bool use
                 return new CharacterHit(FirstTextSourceIndex);
             }
 
-            var currentCharacterHit = characterHit;
-
             var currentRun = GetRunAtCharacterIndex(characterIndex, LogicalDirection.Backward, out var currentPosition);
 
             var previousCharacterHit = characterHit;
@@ -843,46 +841,38 @@ private CharacterHit GetPreviousCharacterHit(CharacterHit characterHit, bool use
             {
                 case ShapedTextRun shapedRun:
                     {
-                        var offset = Math.Max(0, currentPosition - shapedRun.GlyphRun.Metrics.FirstCluster);
+                        //Determine the start of the first hit in local positions.
+                        var runOffset = Math.Max(0, characterIndex - currentPosition);
 
-                        if (offset > 0)
-                        {
-                            currentCharacterHit = new CharacterHit(Math.Max(0, characterHit.FirstCharacterIndex - offset), characterHit.TrailingLength);
-                        }
+                        var firstCluster = shapedRun.GlyphRun.Metrics.FirstCluster;
 
-                        previousCharacterHit = shapedRun.GlyphRun.GetPreviousCaretCharacterHit(currentCharacterHit);
+                        //Current position is a text source index and first cluster is relative to the GlyphRun's buffer.
+                        var textSourceOffset = currentPosition - firstCluster;
 
-                        if (useGraphemeBoundaries)
+                        if (isBackspaceDelete)
                         {
-                            var textPosition = Math.Max(0, previousCharacterHit.FirstCharacterIndex - shapedRun.GlyphRun.Metrics.FirstCluster);
-
-                            var text = shapedRun.GlyphRun.Characters.Slice(textPosition);
-
-                            var graphemeEnumerator = new GraphemeEnumerator(text.Span);
-
                             var length = 0;
 
-                            var clusterLength = Math.Max(0, currentCharacterHit.FirstCharacterIndex + currentCharacterHit.TrailingLength -
-                                previousCharacterHit.FirstCharacterIndex - previousCharacterHit.TrailingLength);
-
-                            while (graphemeEnumerator.MoveNext(out var grapheme))
+                            while (Codepoint.ReadAt(shapedRun.GlyphRun.Characters.Span, length, out var count) != Codepoint.ReplacementCodepoint)
                             {
-                                if (length + grapheme.Length < clusterLength)
+                                if (length + count >= runOffset)
                                 {
-                                    length += grapheme.Length;
-
-                                    continue;
+                                    break;
                                 }
 
-                                previousCharacterHit = new CharacterHit(previousCharacterHit.FirstCharacterIndex + length);
-
-                                break;
+                                length += count;
                             }
-                        }
 
-                        if (offset > 0)
+                            previousCharacterHit = new CharacterHit(characterIndex - runOffset + length);
+                        }
+                        else
                         {
-                            previousCharacterHit = new CharacterHit(previousCharacterHit.FirstCharacterIndex + offset, previousCharacterHit.TrailingLength);
+                            previousCharacterHit = shapedRun.GlyphRun.GetPreviousCaretCharacterHit(new CharacterHit(firstCluster + runOffset));
+
+                            if(textSourceOffset > 0)
+                            {
+                                previousCharacterHit = new CharacterHit(textSourceOffset + previousCharacterHit.FirstCharacterIndex, previousCharacterHit.TrailingLength);
+                            }
                         }
 
                         break;
@@ -1326,8 +1316,6 @@ private TextLineMetrics CreateLineMetrics()
                 }
             }
 
-            var height = descent - ascent + lineGap;
-
             var inkBounds = new Rect();
 
             for (var index = 0; index < _textRuns.Length; index++)
@@ -1363,6 +1351,28 @@ private TextLineMetrics CreateLineMetrics()
                 }
             }
 
+            var halfLineGap = lineGap * 0.5;
+            var naturalHeight = descent - ascent + lineGap;
+            var baseline = -ascent + halfLineGap;
+            var height = naturalHeight;
+
+            if (!double.IsNaN(lineHeight) && !MathUtilities.IsZero(lineHeight))
+            {
+                if (lineHeight <= naturalHeight)
+                {
+                    //Clamp to the specified line height
+                    height = lineHeight;
+                    baseline = -ascent;
+                }
+                else
+                {
+                    // Center the text vertically within the specified line height
+                    height = lineHeight;
+                    var extra = lineHeight - (descent - ascent);
+                    baseline = -ascent + extra / 2;
+                }
+            }
+
             height += lineSpacing;
 
             var width = widthIncludingWhitespace;
@@ -1395,24 +1405,14 @@ private TextLineMetrics CreateLineMetrics()
             }
 
             var extent = inkBounds.Height;
-            //The width of overhanging pixels at the bottom
-            var overhangAfter = inkBounds.Bottom - 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 hasOverflowed = width > _paragraphWidth;
 
-            if (!double.IsNaN(lineHeight) && !MathUtilities.IsZero(lineHeight))
-            {
-                //Center the line
-                var offset = (height - lineHeight) / 2;
-
-                ascent += offset;
-
-                height = lineHeight;
-            }
-
             var start = GetParagraphOffsetX(width, widthIncludingWhitespace);
 
             _inkBounds = inkBounds.Translate(new Vector(start, 0));
@@ -1426,7 +1426,7 @@ private TextLineMetrics CreateLineMetrics()
                 Extent = extent,
                 NewlineLength = newLineLength,
                 Start = start,
-                TextBaseline = -ascent,
+                TextBaseline = baseline,
                 TrailingWhitespaceLength = trailingWhitespaceLength,
                 Width = width,
                 WidthIncludingTrailingWhitespace = widthIncludingWhitespace,

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

@@ -19,6 +19,8 @@ public TextMetrics(IGlyphTypeface glyphTypeface, double fontRenderingEmSize)
 
             LineGap = fontMetrics.LineGap * scale;
 
+            Baseline = -Ascent + LineGap * 0.5;
+
             LineHeight = Descent - Ascent + LineGap;
 
             UnderlineThickness = fontMetrics.UnderlineThickness * scale;
@@ -35,6 +37,11 @@ public TextMetrics(IGlyphTypeface glyphTypeface, double fontRenderingEmSize)
         /// </summary>
         public double FontRenderingEmSize { get; }
 
+        /// <summary>
+        /// Gets the distance from the top to the baseline of the line of text.
+        /// </summary>
+        public double Baseline { get; }
+
         /// <summary>
         /// Gets the recommended distance above the baseline.
         /// </summary>

src/Avalonia.Themes.Fluent/Controls/CheckBox.xaml

@@ -13,6 +13,7 @@
   </Design.PreviewWith>
 
   <StreamGeometry x:Key="CheckMarkPathData">M5.5 10.586 1.707 6.793A1 1 0 0 0 .293 8.207l4.5 4.5a1 1 0 0 0 1.414 0l11-11A1 1 0 0 0 15.793.293L5.5 10.586Z</StreamGeometry>
+  <x:Double x:Key="CheckBoxMinHeight">32</x:Double> 
 
   <ControlTheme x:Key="{x:Type CheckBox}" TargetType="CheckBox">
     <Setter Property="Padding" Value="8,0,0,0" />
@@ -21,7 +22,7 @@
     <Setter Property="HorizontalContentAlignment" Value="Left" />
     <Setter Property="VerticalContentAlignment" Value="Center" />
     <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
-    <Setter Property="MinHeight" Value="32" />
+    <Setter Property="MinHeight" Value="{DynamicResource CheckBoxMinHeight}" />
     <Setter Property="Foreground" Value="{DynamicResource CheckBoxForegroundUnchecked}" />
     <Setter Property="Background" Value="{DynamicResource CheckBoxBackgroundUnchecked}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CheckBoxBorderBrushUnchecked}" />
@@ -35,7 +36,7 @@
                   BorderThickness="{TemplateBinding BorderThickness}"
                   CornerRadius="{TemplateBinding CornerRadius}" />
 
-          <Grid VerticalAlignment="Top" Height="32">
+          <Grid VerticalAlignment="Top" Height="{DynamicResource CheckBoxMinHeight}">
             <Border x:Name="NormalRectangle"
                     BorderBrush="{DynamicResource CheckBoxCheckBackgroundStrokeUnchecked}"
                     Background="{DynamicResource CheckBoxCheckBackgroundFillUnchecked}"

src/Avalonia.Themes.Fluent/Controls/RadioButton.xaml

@@ -11,6 +11,8 @@
     </Border>
   </Design.PreviewWith>
 
+  <x:Double x:Key="RadioButtonMinHeight">32</x:Double>
+  
   <ControlTheme x:Key="{x:Type RadioButton}" TargetType="RadioButton">
     <Setter Property="Background" Value="{DynamicResource RadioButtonBackground}" />
     <Setter Property="Foreground" Value="{DynamicResource RadioButtonForeground}" />
@@ -30,7 +32,7 @@
             BorderThickness="{TemplateBinding BorderThickness}"
             CornerRadius="{TemplateBinding CornerRadius}">
           <Grid ColumnDefinitions="20,*">
-            <Grid Height="32" VerticalAlignment="Top">
+            <Grid Height="{DynamicResource RadioButtonMinHeight}" VerticalAlignment="Top">
 
               <Ellipse
                   Name="OuterEllipse"

src/Avalonia.Themes.Fluent/DensityStyles/Compact.xaml

@@ -21,4 +21,6 @@
   <x:Double x:Key="TabItemMinHeight">28</x:Double>
   <Thickness x:Key="TabItemHeaderMargin">6, 0</Thickness>
   <Thickness x:Key="ButtonPadding">6,4</Thickness>
+  <x:Double x:Key="CheckBoxMinHeight">24</x:Double>
+  <x:Double x:Key="RadioButtonMinHeight">24</x:Double>
 </ResourceDictionary>

tests/Avalonia.Skia.UnitTests/Fonts/Inter-Regular.LineGap800.ttf

@@ -379,6 +379,25 @@ public void Should_Get_Distance_From_CharacterHit_Within_Cluster()
             }
         }
 
+        [Fact]
+        public void Should_Add_Half_LineGap_To_Baseline()
+        {
+            using (Start())
+            {
+                var typeface = new Typeface("resm:Avalonia.Skia.UnitTests.Fonts?assembly=Avalonia.Skia.UnitTests#Inter");
+                var options = new TextShaperOptions(typeface.GlyphTypeface, 14);
+                var shapedBuffer = TextShaper.Current.ShapeText("F", options);
+
+                var textMetrics = new TextMetrics(shapedBuffer.GlyphTypeface, 14);
+
+                var glyphRun = CreateGlyphRun(shapedBuffer);
+
+                var expectedBaseline = -textMetrics.Ascent + textMetrics.LineGap / 2;
+
+                Assert.Equal(expectedBaseline, glyphRun.Metrics.Baseline);
+            }
+        }
+
         private static List<Rect> BuildRects(GlyphRun glyphRun)
         {
             var height = glyphRun.Bounds.Height;