Add new TexBlock and Hit testing APIs

src/SixLabors.Fonts/CaretMovement.cs

@@ -0,0 +1,60 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.Fonts;
+
+/// <summary>
+/// Specifies a caret movement operation within laid-out text.
+/// </summary>
+public enum CaretMovement
+{
+    /// <summary>
+    /// Move to the previous grapheme insertion position.
+    /// </summary>
+    Previous,
+
+    /// <summary>
+    /// Move to the next grapheme insertion position.
+    /// </summary>
+    Next,
+
+    /// <summary>
+    /// Move to the previous Unicode word boundary.
+    /// </summary>
+    PreviousWord,
+
+    /// <summary>
+    /// Move to the next Unicode word boundary.
+    /// </summary>
+    NextWord,
+
+    /// <summary>
+    /// Move to the start of the current line.
+    /// </summary>
+    LineStart,
+
+    /// <summary>
+    /// Move to the end of the current line.
+    /// </summary>
+    LineEnd,
+
+    /// <summary>
+    /// Move to the start of the laid-out text.
+    /// </summary>
+    TextStart,
+
+    /// <summary>
+    /// Move to the end of the laid-out text.
+    /// </summary>
+    TextEnd,
+
+    /// <summary>
+    /// Move to the previous visual line.
+    /// </summary>
+    LineUp,
+
+    /// <summary>
+    /// Move to the next visual line.
+    /// </summary>
+    LineDown
+}

src/SixLabors.Fonts/CaretPlacement.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.Fonts;
+
+/// <summary>
+/// Specifies an absolute caret placement within a laid-out text scope.
+/// </summary>
+public enum CaretPlacement
+{
+    /// <summary>
+    /// Place the caret at the start of the laid-out text scope.
+    /// </summary>
+    Start,
+
+    /// <summary>
+    /// Place the caret at the end of the laid-out text scope.
+    /// </summary>
+    End
+}

src/SixLabors.Fonts/CaretPosition.cs

@@ -0,0 +1,91 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using System.Numerics;
+
+namespace SixLabors.Fonts;
+
+/// <summary>
+/// Represents a caret line in laid-out text.
+/// </summary>
+public readonly struct CaretPosition
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CaretPosition"/> struct.
+    /// </summary>
+    /// <param name="lineIndex">The zero-based line index.</param>
+    /// <param name="graphemeIndex">The grapheme insertion index in the original text.</param>
+    /// <param name="stringIndex">The UTF-16 index in the original text.</param>
+    /// <param name="start">The caret start point in pixel units.</param>
+    /// <param name="end">The caret end point in pixel units.</param>
+    /// <param name="hasSecondary">Whether the caret has a second visual position.</param>
+    /// <param name="secondaryStart">The secondary caret start point in pixel units.</param>
+    /// <param name="secondaryEnd">The secondary caret end point in pixel units.</param>
+    /// <param name="lineNavigationPosition">The position to preserve when moving between visual lines.</param>
+    internal CaretPosition(
+        int lineIndex,
+        int graphemeIndex,
+        int stringIndex,
+        Vector2 start,
+        Vector2 end,
+        bool hasSecondary,
+        Vector2 secondaryStart,
+        Vector2 secondaryEnd,
+        float lineNavigationPosition)
+    {
+        this.LineIndex = lineIndex;
+        this.GraphemeIndex = graphemeIndex;
+        this.StringIndex = stringIndex;
+        this.Start = start;
+        this.End = end;
+        this.HasSecondary = hasSecondary;
+        this.SecondaryStart = secondaryStart;
+        this.SecondaryEnd = secondaryEnd;
+        this.LineNavigationPosition = lineNavigationPosition;
+    }
+
+    /// <summary>
+    /// Gets the zero-based line index.
+    /// </summary>
+    public int LineIndex { get; }
+
+    /// <summary>
+    /// Gets the zero-based grapheme index in the original text.
+    /// </summary>
+    public int GraphemeIndex { get; }
+
+    /// <summary>
+    /// Gets the zero-based UTF-16 code unit index in the original text.
+    /// </summary>
+    public int StringIndex { get; }
+
+    /// <summary>
+    /// Gets the caret start point in pixel units.
+    /// </summary>
+    public Vector2 Start { get; }
+
+    /// <summary>
+    /// Gets the caret end point in pixel units.
+    /// </summary>
+    public Vector2 End { get; }
+
+    /// <summary>
+    /// Gets a value indicating whether a second visual caret position is available.
+    /// </summary>
+    public bool HasSecondary { get; }
+
+    /// <summary>
+    /// Gets the secondary caret start point in pixel units.
+    /// </summary>
+    public Vector2 SecondaryStart { get; }
+
+    /// <summary>
+    /// Gets the secondary caret end point in pixel units.
+    /// </summary>
+    public Vector2 SecondaryEnd { get; }
+
+    /// <summary>
+    /// Gets the position to preserve when moving between visual lines.
+    /// </summary>
+    internal float LineNavigationPosition { get; }
+}

src/SixLabors.Fonts/FileFontMetrics.cs

@@ -126,7 +126,7 @@ internal override bool TryGetMarkAttachmentClass(ushort glyphId, [NotNullWhen(tr
         => this.fontMetrics.Value.TryGetMarkAttachmentClass(glyphId, out markAttachmentClass);
 
     /// <inheritdoc/>
-    public override bool TryGetVariationAxes(out VariationAxis[]? variationAxes)
+    public override bool TryGetVariationAxes(out ReadOnlyMemory<VariationAxis> variationAxes)
         => this.fontMetrics.Value.TryGetVariationAxes(out variationAxes);
 
     /// <inheritdoc/>
@@ -140,11 +140,11 @@ public override bool TryGetGlyphMetrics(
         TextDecorations textDecorations,
         LayoutMode layoutMode,
         ColorFontSupport support,
-        [NotNullWhen(true)] out GlyphMetrics? metrics)
+        [NotNullWhen(true)] out FontGlyphMetrics? metrics)
           => this.fontMetrics.Value.TryGetGlyphMetrics(codePoint, textAttributes, textDecorations, layoutMode, support, out metrics);
 
     /// <inheritdoc />
-    internal override GlyphMetrics GetGlyphMetrics(
+    internal override FontGlyphMetrics GetGlyphMetrics(
         CodePoint codePoint,
         ushort glyphId,
         TextAttributes textAttributes,
@@ -154,7 +154,7 @@ internal override GlyphMetrics GetGlyphMetrics(
         => this.fontMetrics.Value.GetGlyphMetrics(codePoint, glyphId, textAttributes, textDecorations, layoutMode, support);
 
     /// <inheritdoc />
-    public override IReadOnlyList<CodePoint> GetAvailableCodePoints()
+    public override ReadOnlyMemory<CodePoint> GetAvailableCodePoints()
         => this.fontMetrics.Value.GetAvailableCodePoints();
 
     /// <inheritdoc/>
@@ -185,8 +185,8 @@ internal override ReadOnlySpan<float> GetNormalizedCoordinates()
     /// Reads a <see cref="StreamFontMetrics"/> from the specified stream.
     /// </summary>
     /// <param name="path">The file path.</param>
-    /// <returns>a <see cref="StreamFontMetrics"/>.</returns>
-    public static FileFontMetrics[] LoadFontCollection(string path)
+    /// <returns>A read-only memory region containing the font metrics.</returns>
+    public static ReadOnlyMemory<FileFontMetrics> LoadFontCollection(string path)
     {
         using FileStream fs = File.OpenRead(path);
         long startPos = fs.Position;

src/SixLabors.Fonts/Font.cs

@@ -261,7 +261,7 @@ public bool TryGetGlyph(
         [NotNullWhen(true)] out Glyph? glyph)
     {
         TextRun textRun = new() { Start = 0, End = 1, Font = this, TextAttributes = textAttributes, TextDecorations = textDecorations };
-        if (this.FontMetrics.TryGetGlyphMetrics(codePoint, textAttributes, textDecorations, layoutMode, support, out GlyphMetrics? metrics))
+        if (this.FontMetrics.TryGetGlyphMetrics(codePoint, textAttributes, textDecorations, layoutMode, support, out FontGlyphMetrics? metrics))
         {
             glyph = new(metrics.CloneForRendering(textRun), this.Size);
             return true;
@@ -357,10 +357,16 @@ private string LoadFontName()
         }
 
         // Can't find style requested so let's just try returning the default.
-        IEnumerable<FontStyle>? styles = this.Family.GetAvailableStyles();
-        FontStyle defaultStyle = styles.Contains(FontStyle.Regular)
-        ? FontStyle.Regular
-        : styles.First();
+        ReadOnlySpan<FontStyle> styles = this.Family.GetAvailableStyles().Span;
+        FontStyle defaultStyle = styles[0];
+        foreach (FontStyle style in styles)
+        {
+            if (style == FontStyle.Regular)
+            {
+                defaultStyle = FontStyle.Regular;
+                break;
+            }
+        }
 
         this.Family.TryGetMetrics(defaultStyle, out metrics);
         return metrics;

src/SixLabors.Fonts/FontCollection.cs

@@ -61,19 +61,19 @@ public FontFamily Add(Stream stream, out FontDescription description)
         => this.AddImpl(stream, CultureInfo.InvariantCulture, out description);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(string path)
+    public ReadOnlyMemory<FontFamily> AddCollection(string path)
         => this.AddCollection(path, out _);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(string path, out IEnumerable<FontDescription> descriptions)
+    public ReadOnlyMemory<FontFamily> AddCollection(string path, out ReadOnlyMemory<FontDescription> descriptions)
         => this.AddCollectionImpl(path, CultureInfo.InvariantCulture, out descriptions);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(Stream stream)
+    public ReadOnlyMemory<FontFamily> AddCollection(Stream stream)
         => this.AddCollection(stream, out _);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(Stream stream, out IEnumerable<FontDescription> descriptions)
+    public ReadOnlyMemory<FontFamily> AddCollection(Stream stream, out ReadOnlyMemory<FontDescription> descriptions)
         => this.AddCollectionImpl(stream, CultureInfo.InvariantCulture, out descriptions);
 
     /// <inheritdoc/>
@@ -101,25 +101,25 @@ public FontFamily AddWithCulture(Stream stream, CultureInfo culture, out FontDes
         => this.AddImpl(stream, culture, out description);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(string path, CultureInfo culture)
+    public ReadOnlyMemory<FontFamily> AddCollection(string path, CultureInfo culture)
         => this.AddCollection(path, culture, out _);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(
+    public ReadOnlyMemory<FontFamily> AddCollection(
         string path,
         CultureInfo culture,
-        out IEnumerable<FontDescription> descriptions)
+        out ReadOnlyMemory<FontDescription> descriptions)
         => this.AddCollectionImpl(path, culture, out descriptions);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(Stream stream, CultureInfo culture)
+    public ReadOnlyMemory<FontFamily> AddCollection(Stream stream, CultureInfo culture)
         => this.AddCollection(stream, culture, out _);
 
     /// <inheritdoc/>
-    public IEnumerable<FontFamily> AddCollection(
+    public ReadOnlyMemory<FontFamily> AddCollection(
         Stream stream,
         CultureInfo culture,
-        out IEnumerable<FontDescription> descriptions)
+        out ReadOnlyMemory<FontDescription> descriptions)
         => this.AddCollectionImpl(stream, culture, out descriptions);
 
     /// <inheritdoc/>
@@ -178,7 +178,7 @@ IEnumerable<FontMetrics> IReadOnlyFontMetricsCollection.GetAllMetrics(string nam
     }
 
     /// <inheritdoc/>
-    IEnumerable<FontStyle> IReadOnlyFontMetricsCollection.GetAllStyles(string name, CultureInfo culture)
+    ReadOnlyMemory<FontStyle> IReadOnlyFontMetricsCollection.GetAllStyles(string name, CultureInfo culture)
         => ((IReadOnlyFontMetricsCollection)this).GetAllMetrics(name, culture).Select(x => x.Description.Style).ToArray();
 
     /// <inheritdoc/>
@@ -208,47 +208,58 @@ private FontFamily AddImpl(Stream stream, CultureInfo culture, out FontDescripti
         return ((IFontMetricsCollection)this).AddMetrics(metrics, culture);
     }
 
-    private HashSet<FontFamily> AddCollectionImpl(
+    private ReadOnlyMemory<FontFamily> AddCollectionImpl(
         string path,
         CultureInfo culture,
-        out IEnumerable<FontDescription> descriptions)
+        out ReadOnlyMemory<FontDescription> descriptions)
     {
-        FileFontMetrics[] fonts = FileFontMetrics.LoadFontCollection(path);
+        ReadOnlyMemory<FileFontMetrics> fontMetrics = FileFontMetrics.LoadFontCollection(path);
+        ReadOnlySpan<FileFontMetrics> fonts = fontMetrics.Span;
 
         FontDescription[] description = new FontDescription[fonts.Length];
-        HashSet<FontFamily> families = [];
+        FontFamily[] families = new FontFamily[fonts.Length];
+        int familyCount = 0;
         for (int i = 0; i < fonts.Length; i++)
         {
             description[i] = fonts[i].Description;
             FontFamily family = ((IFontMetricsCollection)this).AddMetrics(fonts[i], culture);
-            families.Add(family);
+
+            if (!families.AsSpan(0, familyCount).Contains(family))
+            {
+                families[familyCount++] = family;
+            }
         }
 
         descriptions = description;
-        return families;
+        return new ReadOnlyMemory<FontFamily>(families, 0, familyCount);
     }
 
-    private HashSet<FontFamily> AddCollectionImpl(
+    private ReadOnlyMemory<FontFamily> AddCollectionImpl(
         Stream stream,
         CultureInfo culture,
-        out IEnumerable<FontDescription> descriptions)
+        out ReadOnlyMemory<FontDescription> descriptions)
     {
         long startPos = stream.Position;
         using BigEndianBinaryReader reader = new(stream, true);
         TtcHeader ttcHeader = TtcHeader.Read(reader);
-        List<FontDescription> result = new((int)ttcHeader.NumFonts);
-        HashSet<FontFamily> installedFamilies = [];
+        FontDescription[] result = new FontDescription[(int)ttcHeader.NumFonts];
+        FontFamily[] installedFamilies = new FontFamily[(int)ttcHeader.NumFonts];
+        int familyCount = 0;
         for (int i = 0; i < ttcHeader.NumFonts; ++i)
         {
             stream.Position = startPos + ttcHeader.OffsetTable[i];
             StreamFontMetrics instance = StreamFontMetrics.LoadFont(stream);
-            installedFamilies.Add(((IFontMetricsCollection)this).AddMetrics(instance, culture));
-            FontDescription fontDescription = instance.Description;
-            result.Add(fontDescription);
+            FontFamily family = ((IFontMetricsCollection)this).AddMetrics(instance, culture);
+            result[i] = instance.Description;
+
+            if (!installedFamilies.AsSpan(0, familyCount).Contains(family))
+            {
+                installedFamilies[familyCount++] = family;
+            }
         }
 
         descriptions = result;
-        return installedFamilies;
+        return new ReadOnlyMemory<FontFamily>(installedFamilies, 0, familyCount);
     }
 
     private FontFamily[] FamiliesByCultureImpl(CultureInfo culture)