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

using System;
using System.Numerics;

namespace SixLabors.ImageSharp.Drawing {
  /// <summary>
  /// Represents a simple path segment
  /// </summary>
  public interface ILineSegment
  {
      /// <summary>
      /// Gets the start point.
      /// </summary>
      public PointF StartPoint { get; }

      /// <summary>
      /// Gets the end point.
      /// </summary>
      /// <value>
      /// The end point.
      /// </value>
      public PointF EndPoint { get; }

      /// <summary>
      /// Gets the bounds of the linearized segment output.
      /// </summary>
      public RectangleF Bounds { get; }

      /// <summary>
      /// Returns the number of linear vertices emitted by this segment when flattened under the supplied
      /// device-space <paramref name="scale"/>.
      /// </summary>
      /// <param name="scale">The X/Y scale at which curves are flattened. Pass <see cref="Vector2.One"/> for local-space counts.</param>
      /// <returns>The number of linear vertices this segment emits.</returns>
      public int LinearVertexCount(Vector2 scale);

      /// <summary>
      /// Writes the segment's linearized points to <paramref name="destination"/>, baked at the supplied
      /// device-space <paramref name="scale"/>.
      /// </summary>
      /// <param name="destination">The destination point span.</param>
      /// <param name="skipFirstPoint">Whether to skip the first emitted point.</param>
      /// <param name="scale">The X/Y scale at which curves are flattened. Pass <see cref="Vector2.One"/> for local-space output.</param>
      public void CopyTo(Span<PointF> destination, bool skipFirstPoint, Vector2 scale);

      /// <summary>
      /// Transforms the current LineSegment using specified matrix.
      /// </summary>
      /// <param name="matrix">The matrix.</param>
      /// <returns>A line segment with the matrix applied to it.</returns>
      public ILineSegment Transform(Matrix4x4 matrix);
  }
}