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

using System.Diagnostics.CodeAnalysis;
using SixLabors.ImageSharp.Memory;
using SixLabors.ImageSharp.PixelFormats;

namespace SixLabors.ImageSharp.Drawing.Processing.Backends {
  /// <summary>
  /// Canvas frame backed by a <see cref="Buffer2DRegion{T}"/>.
  /// </summary>
  /// <typeparam name="TPixel">The pixel format.</typeparam>
  public sealed class MemoryCanvasFrame<TPixel> : ICanvasFrame<TPixel>
      where TPixel : unmanaged, IPixel<TPixel>
  {
      private readonly Buffer2DRegion<TPixel> region;

      /// <summary>
      /// Initializes a new instance of the <see cref="MemoryCanvasFrame{TPixel}"/> class.
      /// </summary>
      /// <param name="region">The pixel buffer region backing this frame.</param>
      public MemoryCanvasFrame(Buffer2DRegion<TPixel> region)
      {
          Guard.NotNull(region.Buffer, nameof(region));
          this.region = region;
      }

      /// <inheritdoc />
      public Rectangle Bounds => this.region.Bounds;

      /// <inheritdoc />
      public bool TryGetCpuRegion(out Buffer2DRegion<TPixel> region)
      {
          region = this.region;
          return true;
      }

      /// <inheritdoc />
      public bool TryGetNativeSurface([NotNullWhen(true)] out NativeSurface? surface)
      {
          surface = null;
          return false;
      }
  }
}