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

namespace SixLabors.ImageSharp.Drawing {
  /// <summary>
  /// Describes a single contour within a <see cref="LinearGeometry"/>.
  /// </summary>
  /// <remarks>
  /// A contour identifies a contiguous point run in <see cref="LinearGeometry.Points"/> and the corresponding range in
  /// the derived segment stream exposed by <see cref="LinearGeometry.GetSegments"/>.
  /// </remarks>
  public readonly struct LinearContour
  {
      /// <summary>
      /// Gets the zero-based index of the first point belonging to this contour in <see cref="LinearGeometry.Points"/>.
      /// </summary>
      public required int PointStart { get; init; }

      /// <summary>
      /// Gets the number of stored points belonging to this contour.
      /// </summary>
      public required int PointCount { get; init; }

      /// <summary>
      /// Gets the zero-based index of the first derived segment belonging to this contour.
      /// </summary>
      public required int SegmentStart { get; init; }

      /// <summary>
      /// Gets the number of derived segments belonging to this contour.
      /// </summary>
      public required int SegmentCount { get; init; }

      /// <summary>
      /// Gets a value indicating whether the contour is closed.
      /// </summary>
      /// <remarks>
      /// When <see langword="true"/>, the final derived segment for the contour joins the last stored point back to
      /// the first stored point. Closed contours do not duplicate the first point at the end of their stored point run.
      /// </remarks>
      public required bool IsClosed { get; init; }
  }
}