Support text runs.

samples/DrawWithImageSharp/Program.cs

@@ -8,6 +8,7 @@
 using System.Numerics;
 using System.Text;
 using DrawWithImageSharp;
+using SixLabors.Fonts.Unicode;
 using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.Drawing;
 using SixLabors.ImageSharp.Drawing.Processing;
@@ -33,22 +34,43 @@ public static void Main(string[] args)
             FontFamily colorEmoji = fonts.Add(@"Fonts\Twemoji Mozilla.ttf");
             FontFamily font2 = fonts.Add(@"Fonts\OpenSans-Regular.ttf");
             FontFamily sunflower = fonts.Add(@"Fonts\Sunflower-Medium.ttf");
+            FontFamily bugzilla = fonts.Add(@"Fonts\me_quran_volt_newmet.ttf");
 
 #if OS_WINDOWS
             FontFamily emojiFont = SystemFonts.Get("Segoe UI Emoji");
             FontFamily uiFont = SystemFonts.Get("Segoe UI");
             FontFamily arabicFont = SystemFonts.Get("Dubai");
 
             FontFamily tahoma = SystemFonts.Get("Tahoma");
+            var textRuns = new List<TextRun>
+            {
+                new TextRun { Start = 4, End = 9, Font = uiFont.CreateFont(72, FontStyle.Bold), TextAttributes = TextAttributes.Superscript, TextDecorations = TextDecorations.Underline | TextDecorations.Strikeout | TextDecorations.Overline },
+                new TextRun { Start = 26, End = 30, Font = uiFont.CreateFont(72, FontStyle.Italic), TextAttributes = TextAttributes.Subscript, TextDecorations = TextDecorations.Strikeout | TextDecorations.Underline | TextDecorations.Overline }
+            };
+
+            RenderText(uiFont, "The quick brown fox jumps over the lazy dog", pointSize: 72, textRuns: textRuns);
+
+            string arabic = "بِسْمِ ٱللَّهِ ٱلرَّحْمَٟنِ ٱلرَّحِيمِ";
+            textRuns = new List<TextRun>
+            {
+                new TextRun { Start = 0, End = CodePoint.GetCodePointCount(arabic), TextDecorations = TextDecorations.Underline }
+            };
+
+            RenderText(uiFont, arabic, pointSize: 72, textRuns: textRuns);
+
+            textRuns = new List<TextRun>
+            {
+                new TextRun { Start = 0, End = CodePoint.GetCodePointCount(arabic), TextDecorations = TextDecorations.Underline }
+            };
+            RenderText(bugzilla, arabic, pointSize: 72, textRuns: textRuns);
+
             RenderText(font2, "\uFB01", pointSize: 11.25F);
             RenderText(fontWoff2, "\uFB01", pointSize: 11.25F);
             RenderText(tahoma, "p", pointSize: 11.25F);
             RenderText(tahoma, "Lorem ipsum dolor sit amet", pointSize: 11.25F);
             RenderText(uiFont, "Soft\u00ADHyphen", pointSize: 72);
-            FontFamily bugzilla = fonts.Add(@"Fonts\me_quran_volt_newmet.ttf");
 
             RenderText(uiFont, "Soft\u00ADHyphen", pointSize: 72);
-            RenderText(bugzilla, "بِسْمِ ٱللَّهِ ٱلرَّحْمَٟنِ ٱلرَّحِيمِ", pointSize: 72);
 
             RenderText(uiFont, "first\n\n\n\nl", pointSize: 20, fallbackFonts: new[] { font2 });
 
@@ -182,12 +204,18 @@ public static void RenderText(TextOptions options, string text)
             SaveImage(options, text, (int)size.Width, (int)size.Height, options.Font.Name, text + ".png");
         }
 
-        public static void RenderText(FontFamily font, string text, float pointSize = 12, IEnumerable<FontFamily> fallbackFonts = null)
+        public static void RenderText(
+            FontFamily font,
+            string text,
+            float pointSize = 12,
+            IEnumerable<FontFamily> fallbackFonts = null,
+            IEnumerable<TextRun> textRuns = null)
             => RenderText(
                 new TextOptions(new Font(font, pointSize))
                 {
-                    WrappingLength = 400,
-                    FallbackFontFamilies = fallbackFonts?.ToArray()
+                    // WrappingLength = 400,
+                    FallbackFontFamilies = fallbackFonts?.ToArray(),
+                    TextRuns = textRuns?.ToArray()
                 },
                 text);
 

src/SixLabors.Fonts/BigEndianBinaryReader.cs

@@ -112,17 +112,14 @@ public TEnum ReadInt16<TEnum>()
         public ushort ReadUFWORD() => this.ReadUInt16();
 
         /// <summary>
-        /// Reads a 32-bit signed integer from the stream.
+        /// Reads a fixed 32-bit value from the stream.
         /// 4 bytes are read.
         /// </summary>
-        /// <returns>The 32-bit integer read.</returns>
+        /// <returns>The 32-bit value read.</returns>
         public float ReadFixed()
         {
             this.ReadInternal(this.buffer, 4);
-
-            int value = BinaryPrimitives.ReadInt32BigEndian(this.buffer);
-
-            return Unsafe.As<int, float>(ref value);
+            return BinaryPrimitives.ReadInt32BigEndian(this.buffer) / 65536F;
         }
 
         /// <summary>

src/SixLabors.Fonts/FileFontMetrics.cs

@@ -70,6 +70,45 @@ internal FileFontMetrics(FontDescription description, string path, long offset)
         /// <inheritdoc/>
         public override short AdvanceHeightMax => this.metrics.Value.AdvanceHeightMax;
 
+        /// <inheritdoc/>
+        public override short SubscriptXSize => this.metrics.Value.SubscriptXSize;
+
+        /// <inheritdoc/>
+        public override short SubscriptYSize => this.metrics.Value.SubscriptYSize;
+
+        /// <inheritdoc/>
+        public override short SubscriptXOffset => this.metrics.Value.SubscriptXOffset;
+
+        /// <inheritdoc/>
+        public override short SubscriptYOffset => this.metrics.Value.SubscriptYOffset;
+
+        /// <inheritdoc/>
+        public override short SuperscriptXSize => this.metrics.Value.SuperscriptXSize;
+
+        /// <inheritdoc/>
+        public override short SuperscriptYSize => this.metrics.Value.SuperscriptYSize;
+
+        /// <inheritdoc/>
+        public override short SuperscriptXOffset => this.metrics.Value.SuperscriptXOffset;
+
+        /// <inheritdoc/>
+        public override short SuperscriptYOffset => this.metrics.Value.SuperscriptYOffset;
+
+        /// <inheritdoc/>
+        public override short StrikeoutSize => this.metrics.Value.StrikeoutSize;
+
+        /// <inheritdoc/>
+        public override short StrikeoutPosition => this.metrics.Value.StrikeoutPosition;
+
+        /// <inheritdoc/>
+        public override short UnderlinePosition => this.metrics.Value.UnderlinePosition;
+
+        /// <inheritdoc/>
+        public override short UnderlineThickness => this.metrics.Value.UnderlineThickness;
+
+        /// <inheritdoc/>
+        public override float ItalicAngle => this.metrics.Value.ItalicAngle;
+
         /// <inheritdoc/>
         internal override bool TryGetGlyphId(CodePoint codePoint, out ushort glyphId)
             => this.metrics.Value.TryGetGlyphId(codePoint, out glyphId);

src/SixLabors.Fonts/Font.cs

@@ -149,10 +149,21 @@ public bool TryGetPath([NotNullWhen(true)] out string? path)
         /// <param name="support">Options for enabling color font support during layout and rendering.</param>
         /// <returns>Returns the glyph</returns>
         public IEnumerable<Glyph> GetGlyphs(CodePoint codePoint, ColorFontSupport support)
+            => this.GetGlyphs(codePoint, TextAttributes.None, support);
+
+        /// <summary>
+        /// Gets the glyphs for the given codepoint.
+        /// </summary>
+        /// <param name="codePoint">The code point of the character.</param>
+        /// <param name="textAttributes">The text attributes to apply to the glyphs.</param>
+        /// <param name="support">Options for enabling color font support during layout and rendering.</param>
+        /// <returns>Returns the glyph</returns>
+        public IEnumerable<Glyph> GetGlyphs(CodePoint codePoint, TextAttributes textAttributes, ColorFontSupport support)
         {
+            TextRun textRun = new() { Start = 0, End = 1, Font = this, TextAttributes = textAttributes };
             foreach (GlyphMetrics metrics in this.FontMetrics.GetGlyphMetrics(codePoint, support))
             {
-                yield return new(metrics, this.Size);
+                yield return new(GlyphMetrics.CloneForRendering(metrics, textRun, codePoint), this.Size);
             }
         }
 

src/SixLabors.Fonts/FontMetrics.cs

@@ -67,6 +67,72 @@ internal FontMetrics()
         /// </summary>
         public abstract short AdvanceHeightMax { get; }
 
+        /// <summary>
+        /// Gets the recommended horizontal size in font design units for subscripts for this font.
+        /// </summary>
+        public abstract short SubscriptXSize { get; }
+
+        /// <summary>
+        /// Gets the recommended vertical size in font design units for subscripts for this font.
+        /// </summary>
+        public abstract short SubscriptYSize { get; }
+
+        /// <summary>
+        /// Gets the recommended horizontal offset in font design units for subscripts for this font.
+        /// </summary>
+        public abstract short SubscriptXOffset { get; }
+
+        /// <summary>
+        /// Gets the recommended vertical offset in font design units for subscripts for this font.
+        /// </summary>
+        public abstract short SubscriptYOffset { get; }
+
+        /// <summary>
+        /// Gets the recommended horizontal size in font design units for superscripts for this font.
+        /// </summary>
+        public abstract short SuperscriptXSize { get; }
+
+        /// <summary>
+        /// Gets the recommended vertical size in font design units for superscripts for this font.
+        /// </summary>
+        public abstract short SuperscriptYSize { get; }
+
+        /// <summary>
+        /// Gets the recommended horizontal offset in font design units for superscripts for this font.
+        /// </summary>
+        public abstract short SuperscriptXOffset { get; }
+
+        /// <summary>
+        /// Gets the recommended vertical offset in font design units for superscripts for this font.
+        /// </summary>
+        public abstract short SuperscriptYOffset { get; }
+
+        /// <summary>
+        /// Gets thickness of the strikeout stroke in font design units.
+        /// </summary>
+        public abstract short StrikeoutSize { get; }
+
+        /// <summary>
+        /// Gets the position of the top of the strikeout stroke relative to the baseline in font design units.
+        /// </summary>
+        public abstract short StrikeoutPosition { get; }
+
+        /// <summary>
+        /// Gets the suggested distance of the top of the underline from the baseline (negative values indicate below baseline).
+        /// </summary>
+        public abstract short UnderlinePosition { get; }
+
+        /// <summary>
+        /// Gets the suggested values for the underline thickness. In general, the underline thickness should match the thickness of
+        /// the underscore character (U+005F LOW LINE), and should also match the strikeout thickness, which is specified in the OS/2 table.
+        /// </summary>
+        public abstract short UnderlineThickness { get; }
+
+        /// <summary>
+        /// Gets the italic angle in counter-clockwise degrees from the vertical. Zero for upright text, negative for text that leans to the right (forward).
+        /// </summary>
+        public abstract float ItalicAngle { get; }
+
         /// <summary>
         /// Gets the specified glyph id matching the codepoint.
         /// </summary>

src/SixLabors.Fonts/GlyphLayout.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.Numerics;
-using System.Text;
 using SixLabors.Fonts.Unicode;
 
 namespace SixLabors.Fonts
@@ -15,14 +14,21 @@ internal readonly struct GlyphLayout
         internal GlyphLayout(
             Glyph glyph,
             Vector2 location,
+            float ascender,
+            float descender,
+            float linegap,
+            float lineHeight,
             float width,
             float height,
-            float lineHeight,
             bool isStartOfLine)
         {
-            this.LineHeight = lineHeight;
             this.Glyph = glyph;
+            this.CodePoint = glyph.GlyphMetrics.CodePoint;
             this.Location = location;
+            this.Ascender = ascender;
+            this.Descender = descender;
+            this.LineGap = linegap;
+            this.LineHeight = lineHeight;
             this.Width = width;
             this.Height = height;
             this.IsStartOfLine = isStartOfLine;
@@ -33,26 +39,46 @@ internal GlyphLayout(
         /// </summary>
         public Glyph Glyph { get; }
 
+        /// <summary>
+        /// Gets the codepoint represented by this glyph.
+        /// </summary>
+        public CodePoint CodePoint { get; }
+
         /// <summary>
         /// Gets the location.
         /// </summary>
         public Vector2 Location { get; }
 
         /// <summary>
-        /// Gets the width.
+        /// Gets the ascender
         /// </summary>
-        public float Width { get; }
+        public float Ascender { get; }
 
         /// <summary>
-        /// Gets the height.
+        /// Gets the ascender
         /// </summary>
-        public float Height { get; }
+        public float Descender { get; }
+
+        /// <summary>
+        /// Gets the lie gap
+        /// </summary>
+        public float LineGap { get; }
 
         /// <summary>
         /// Gets the line height of the glyph.
         /// </summary>
         public float LineHeight { get; }
 
+        /// <summary>
+        /// Gets the width.
+        /// </summary>
+        public float Width { get; }
+
+        /// <summary>
+        /// Gets the height.
+        /// </summary>
+        public float Height { get; }
+
         /// <summary>
         /// Gets a value indicating whether this glyph is the first glyph on a new line.
         /// </summary>
@@ -62,7 +88,7 @@ internal GlyphLayout(
         /// Gets a value indicating whether the glyph represents a whitespace character.
         /// </summary>
         /// <returns>The <see cref="bool"/>.</returns>
-        public bool IsWhiteSpace() => CodePoint.IsWhiteSpace(this.Glyph.GlyphMetrics.CodePoint);
+        public bool IsWhiteSpace() => CodePoint.IsWhiteSpace(this.CodePoint);
 
         internal FontRectangle BoundingBox(float dpi)
         {
@@ -79,33 +105,10 @@ internal FontRectangle BoundingBox(float dpi)
         /// <inheritdoc/>
         public override string ToString()
         {
-            var sb = new StringBuilder();
-            if (this.IsStartOfLine)
-            {
-                sb.Append('@');
-                sb.Append(' ');
-            }
-
-            if (this.IsWhiteSpace())
-            {
-                sb.Append('!');
-            }
-
-            sb.Append('\'');
-            sb.Append(this.Glyph.GlyphMetrics.CodePoint.ToDebuggerDisplay());
-
-            sb.Append('\'');
-            sb.Append(' ');
-
-            sb.Append(this.Location.X);
-            sb.Append(',');
-            sb.Append(this.Location.Y);
-            sb.Append(' ');
-            sb.Append(this.Width);
-            sb.Append('x');
-            sb.Append(this.Height);
-
-            return sb.ToString();
+            string s = this.IsStartOfLine ? "@ " : string.Empty;
+            string ws = this.IsWhiteSpace() ? "!" : string.Empty;
+            Vector2 l = this.Location;
+            return $"{s}{ws}{this.CodePoint.ToDebuggerDisplay()} {l.X},{l.Y} {this.Width}x{this.Height}";
         }
     }
 }