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

using System.Numerics;
using SixLabors.Fonts.Rendering;

namespace SixLabors.Fonts {
  /// <summary>
  /// Represents a font-specific glyph at the point size used for layout and rendering.
  /// </summary>
  public readonly struct Glyph
  {
      private readonly float pointSize;

      internal Glyph(FontGlyphMetrics glyphMetrics, float pointSize)
      {
          this.GlyphMetrics = glyphMetrics;
          this.pointSize = pointSize;
      }

      /// <summary>
      /// Gets the font metrics for this glyph.
      /// </summary>
      public FontGlyphMetrics GlyphMetrics { get; }

      /// <summary>
      /// Calculates the rendered glyph bounds for the specified layout mode and origin.
      /// </summary>
      /// <param name="mode">The glyph layout mode to measure with.</param>
      /// <param name="glyphOrigin">The glyph origin to calculate the bounds from.</param>
      /// <param name="dpi">The DPI to measure the glyph at.</param>
      /// <returns>The rendered glyph bounds.</returns>
      public FontRectangle BoundingBox(GlyphLayoutMode mode, Vector2 glyphOrigin, float dpi)
          => this.GlyphMetrics.GetBoundingBox(mode, glyphOrigin, this.pointSize * dpi);

      /// <summary>
      /// Renders the glyph to the render surface.
      /// </summary>
      /// <param name="surface">The target render surface.</param>
      /// <param name="graphemeIndex">The index of the grapheme this glyph is part of.</param>
      /// <param name="glyphOrigin">The origin used to render the glyph outline.</param>
      /// <param name="decorationOrigin">The origin used to render text decorations.</param>
      /// <param name="mode">The glyph layout mode to render using.</param>
      /// <param name="options">The options to render using.</param>
      internal void RenderTo(
          IGlyphRenderer surface,
          int graphemeIndex,
          Vector2 glyphOrigin,
          Vector2 decorationOrigin,
          GlyphLayoutMode mode,
          TextOptions options)
          => this.GlyphMetrics.RenderTo(surface, graphemeIndex, glyphOrigin, decorationOrigin, mode, options);
  }
}