Update RotateProcessor{TPixel}.cs

src/ImageSharp/Processing/Processors/Transforms/RotateProcessor{TPixel}.cs

@@ -2,7 +2,9 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -15,6 +17,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
     internal class RotateProcessor<TPixel> : AffineTransformProcessor<TPixel>
         where TPixel : struct, IPixel<TPixel>
     {
+        private float degrees;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="RotateProcessor{TPixel}"/> class.
         /// </summary>
@@ -24,11 +28,18 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <param name="sourceRectangle">The source area to process for the current processor instance.</param>
         public RotateProcessor(Configuration configuration, RotateProcessor definition, Image<TPixel> source, Rectangle sourceRectangle)
             : base(configuration, definition, source, sourceRectangle)
+            => this.degrees = definition.Degrees;
+
+        /// <inheritdoc/>
+        protected override void OnFrameApply(ImageFrame<TPixel> source, ImageFrame<TPixel> destination)
         {
-            this.Degrees = definition.Degrees;
+            if (this.OptimizedApply(source, destination, this.Configuration))
-        }
+            {
+                return;
+            }
 
-        private float Degrees { get; }
+            base.OnFrameApply(source, destination);
+        }
 
         /// <inheritdoc/>
         protected override void AfterImageApply(Image<TPixel> destination)
@@ -39,7 +50,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                 return;
             }
 
-            if (MathF.Abs(WrapDegrees(this.Degrees)) < Constants.Epsilon)
+            if (MathF.Abs(WrapDegrees(this.degrees)) < Constants.Epsilon)
             {
                 // No need to do anything so return.
                 return;
@@ -50,17 +61,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             base.AfterImageApply(destination);
         }
 
-        /// <inheritdoc/>
-        protected override void OnFrameApply(ImageFrame<TPixel> source, ImageFrame<TPixel> destination)
-        {
-            if (this.OptimizedApply(source, destination, this.Configuration))
-            {
-                return;
-            }
-
-            base.OnFrameApply(source, destination);
-        }
-
         /// <summary>
         /// Wraps a given angle in degrees so that it falls withing the 0-360 degree range
         /// </summary>
@@ -93,7 +93,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             Configuration configuration)
         {
             // Wrap the degrees to keep within 0-360 so we can apply optimizations when possible.
-            float degrees = WrapDegrees(this.Degrees);
+            float degrees = WrapDegrees(this.degrees);
 
             if (MathF.Abs(degrees) < Constants.Epsilon)
             {
@@ -131,25 +131,10 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <param name="configuration">The configuration.</param>
         private void Rotate180(ImageFrame<TPixel> source, ImageFrame<TPixel> destination, Configuration configuration)
         {
-            int width = source.Width;
-            int height = source.Height;
-
             ParallelRowIterator.IterateRows(
                 source.Bounds(),
                 configuration,
-                rows =>
+                new Rotate180RowIntervalAction(source.Width, source.Height, source, destination));
-                    {
-                        for (int y = rows.Min; y < rows.Max; y++)
-                        {
-                            Span<TPixel> sourceRow = source.GetPixelRowSpan(y);
-                            Span<TPixel> targetRow = destination.GetPixelRowSpan(height - y - 1);
-
-                            for (int x = 0; x < width; x++)
-                            {
-                                targetRow[width - x - 1] = sourceRow[x];
-                            }
-                        }
-                    });
         }
 
         /// <summary>
@@ -160,31 +145,10 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <param name="configuration">The configuration.</param>
         private void Rotate270(ImageFrame<TPixel> source, ImageFrame<TPixel> destination, Configuration configuration)
         {
-            int width = source.Width;
-            int height = source.Height;
-            Rectangle destinationBounds = destination.Bounds();
-
             ParallelRowIterator.IterateRows(
                 source.Bounds(),
                 configuration,
-                rows =>
+                new Rotate270RowIntervalAction(destination.Bounds(), source.Width, source.Height, source, destination));
-                    {
-                        for (int y = rows.Min; y < rows.Max; y++)
-                        {
-                            Span<TPixel> sourceRow = source.GetPixelRowSpan(y);
-                            for (int x = 0; x < width; x++)
-                            {
-                                int newX = height - y - 1;
-                                newX = height - newX - 1;
-                                int newY = width - x - 1;
-
-                                if (destinationBounds.Contains(newX, newY))
-                                {
-                                    destination[newX, newY] = sourceRow[x];
-                                }
-                            }
-                        }
-                    });
         }
 
         /// <summary>
@@ -195,28 +159,131 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <param name="configuration">The configuration.</param>
         private void Rotate90(ImageFrame<TPixel> source, ImageFrame<TPixel> destination, Configuration configuration)
         {
-            int width = source.Width;
-            int height = source.Height;
-            Rectangle destinationBounds = destination.Bounds();
-
             ParallelRowIterator.IterateRows(
                 source.Bounds(),
                 configuration,
-                rows =>
+                new Rotate90RowIntervalAction(destination.Bounds(), source.Width, source.Height, source, destination));
+        }
+
+        private readonly struct Rotate180RowIntervalAction : IRowIntervalAction
+        {
+            private readonly int width;
+            private readonly int height;
+            private readonly ImageFrame<TPixel> source;
+            private readonly ImageFrame<TPixel> destination;
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public Rotate180RowIntervalAction(
+                int width,
+                int height,
+                ImageFrame<TPixel> source,
+                ImageFrame<TPixel> destination)
+            {
+                this.width = width;
+                this.height = height;
+                this.source = source;
+                this.destination = destination;
+            }
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public void Invoke(in RowInterval rows)
+            {
+                for (int y = rows.Min; y < rows.Max; y++)
+                {
+                    Span<TPixel> sourceRow = this.source.GetPixelRowSpan(y);
+                    Span<TPixel> targetRow = this.destination.GetPixelRowSpan(this.height - y - 1);
+
+                    for (int x = 0; x < this.width; x++)
+                    {
+                        targetRow[this.width - x - 1] = sourceRow[x];
+                    }
+                }
+            }
+        }
+
+        private readonly struct Rotate270RowIntervalAction : IRowIntervalAction
+        {
+            private readonly Rectangle bounds;
+            private readonly int width;
+            private readonly int height;
+            private readonly ImageFrame<TPixel> source;
+            private readonly ImageFrame<TPixel> destination;
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public Rotate270RowIntervalAction(
+                Rectangle bounds,
+                int width,
+                int height,
+                ImageFrame<TPixel> source,
+                ImageFrame<TPixel> destination)
+            {
+                this.bounds = bounds;
+                this.width = width;
+                this.height = height;
+                this.source = source;
+                this.destination = destination;
+            }
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public void Invoke(in RowInterval rows)
+            {
+                for (int y = rows.Min; y < rows.Max; y++)
+                {
+                    Span<TPixel> sourceRow = this.source.GetPixelRowSpan(y);
+                    for (int x = 0; x < this.width; x++)
+                    {
+                        int newX = this.height - y - 1;
+                        newX = this.height - newX - 1;
+                        int newY = this.width - x - 1;
+
+                        if (this.bounds.Contains(newX, newY))
+                        {
+                            this.destination[newX, newY] = sourceRow[x];
+                        }
+                    }
+                }
+            }
+        }
+
+        private readonly struct Rotate90RowIntervalAction : IRowIntervalAction
+        {
+            private readonly Rectangle bounds;
+            private readonly int width;
+            private readonly int height;
+            private readonly ImageFrame<TPixel> source;
+            private readonly ImageFrame<TPixel> destination;
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public Rotate90RowIntervalAction(
+                Rectangle bounds,
+                int width,
+                int height,
+                ImageFrame<TPixel> source,
+                ImageFrame<TPixel> destination)
+            {
+                this.bounds = bounds;
+                this.width = width;
+                this.height = height;
+                this.source = source;
+                this.destination = destination;
+            }
+
+            [MethodImpl(InliningOptions.ShortMethod)]
+            public void Invoke(in RowInterval rows)
+            {
+                for (int y = rows.Min; y < rows.Max; y++)
+                {
+                    Span<TPixel> sourceRow = this.source.GetPixelRowSpan(y);
+                    int newX = this.height - y - 1;
+                    for (int x = 0; x < this.width; x++)
                     {
-                        for (int y = rows.Min; y < rows.Max; y++)
+                        if (this.bounds.Contains(newX, x))
                         {
-                            Span<TPixel> sourceRow = source.GetPixelRowSpan(y);
+                            this.destination[newX, x] = sourceRow[x];
-                            int newX = height - y - 1;
-                            for (int x = 0; x < width; x++)
-                            {
-                                if (destinationBounds.Contains(newX, x))
-                                {
-                                    destination[newX, x] = sourceRow[x];
-                                }
-                            }
                         }
-                    });
+                    }
+                }
+            }
         }
     }
 }