// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

namespace SixLabors.Fonts {
  /// <content>
  /// Visitor types for streaming laid-out glyphs through the layout pipeline.
  /// </content>
  internal static partial class TextLayout
  {
      /// <summary>
      /// Receives laid-out glyphs streamed from the layout pipeline.
      /// Implementations are value types so the generic dispatch is specialized by the JIT and no boxing or
      /// delegate allocation is required.
      /// </summary>
      internal interface IGlyphLayoutVisitor
      {
          /// <summary>
          /// Invoked before glyphs are streamed for a laid-out line.
          /// </summary>
          /// <param name="lineIndex">The zero-based index of the line in the line-broken text box.</param>
          public void BeginLine(int lineIndex);

          /// <summary>
          /// Invoked once for each laid-out glyph in layout order.
          /// </summary>
          /// <param name="glyph">The laid-out glyph.</param>
          public void Visit(in GlyphLayout glyph);

          /// <summary>
          /// Invoked after glyphs have been streamed for a laid-out line.
          /// </summary>
          public void EndLine();
      }
  }
}