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

using SixLabors.ImageSharp.Processing;

namespace SixLabors.ImageSharp.Drawing.Processing {
  /// <summary>
  /// Represents the per-frame painting callback executed by <see cref="PaintExtensions.Paint(IImageProcessingContext, CanvasAction)"/>.
  /// </summary>
  /// <param name="canvas">The drawing canvas for the current image frame.</param>
  public delegate void CanvasAction(DrawingCanvas canvas);

  /// <summary>
  /// Adds image-processing extensions that paint each frame through <see cref="DrawingCanvas"/>.
  /// </summary>
  public static class PaintExtensions
  {
      /// <summary>
      /// Paints each image frame using drawing options from the current context.
      /// </summary>
      /// <param name="source">The image processing context to paint.</param>
      /// <param name="action">The per-frame painting callback.</param>
      /// <returns>The <see cref="IImageProcessingContext"/> so additional processing operations can be chained.</returns>
      public static IImageProcessingContext Paint(
          this IImageProcessingContext source,
          CanvasAction action)
          => source.Paint(source.GetDrawingOptions(), action);

      /// <summary>
      /// Paints each image frame using the supplied drawing options.
      /// </summary>
      /// <param name="source">The image processing context to paint.</param>
      /// <param name="options">The drawing options applied when creating each frame canvas.</param>
      /// <param name="action">The per-frame painting callback.</param>
      /// <returns>The <see cref="IImageProcessingContext"/> so additional processing operations can be chained.</returns>
      public static IImageProcessingContext Paint(
          this IImageProcessingContext source,
          DrawingOptions options,
          CanvasAction action)
      {
          Guard.NotNull(options, nameof(options));
          Guard.NotNull(action, nameof(action));

          return source.ApplyProcessor(new PaintProcessor(options, action));
      }
  }
}