pooling YCbCrImage contents

src/ImageSharp/Formats/Jpg/Components/Decoder/JpegPixelArea.cs

@@ -25,7 +25,7 @@ namespace ImageSharp.Formats.Jpg
             int size = width * height;
             //var pixels = ArrayPool<byte>.Shared.Rent(size);
             //Array.Clear(pixels, 0, size);
-            var pixels = ArrayPoolManager<byte>.RentCleanArray(size);
+            var pixels = CleanPooler<byte>.RentCleanArray(size);
             return new JpegPixelArea(pixels, width, 0);
         }
 
@@ -39,7 +39,7 @@ namespace ImageSharp.Formats.Jpg
         public void ReturnPooled()
         {
             if (this.Pixels == null) return;
-            ArrayPoolManager<byte>.ReturnArray(this.Pixels);
+            CleanPooler<byte>.ReturnArray(this.Pixels);
             this.Pixels = null;
         }
 
@@ -59,27 +59,7 @@ namespace ImageSharp.Formats.Jpg
         /// Gets or sets the offset
         /// </summary>
         public int Offset { get; private set; }
-
-        /// <summary>
-        /// Gets an image made up of a subset of the originals pixels.
-        /// </summary>
-        /// <param name="x">The x-coordinate of the image.</param>
-        /// <param name="y">The y-coordinate of the image.</param>
-        /// <param name="width">The width.</param>
-        /// <param name="height">The height.</param>
-        /// <returns>
-        /// The <see cref="JpegPixelArea"/>.
-        /// </returns>
-        public JpegPixelArea Subimage(int x, int y, int width, int height)
-        {
-            return new JpegPixelArea
-            {
-                Stride = width,
-                Pixels = this.Pixels,
-                Offset = (y * this.Stride) + x
-            };
-        }
-
+       
         /// <summary>
         /// Get the subarea that belongs to the given block indices
         /// </summary>

src/ImageSharp/Formats/Jpg/Components/Decoder/YCbCrImage.cs

@@ -5,12 +5,13 @@
 
 namespace ImageSharp.Formats.Jpg
 {
+    using System;
     using System.Buffers;
 
     /// <summary>
     /// Represents an image made up of three color components (luminance, blue chroma, red chroma)
     /// </summary>
-    internal class YCbCrImage
+    internal class YCbCrImage : IDisposable
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="YCbCrImage"/> class.
@@ -18,14 +19,16 @@ namespace ImageSharp.Formats.Jpg
         /// <param name="width">The width.</param>
         /// <param name="height">The height.</param>
         /// <param name="ratio">The ratio.</param>
-        public YCbCrImage(int width, int height, YCbCrSubsampleRatio ratio)
+        public YCbCrImage(int width, int height, YCbCrSubsampleRatio ratio, int yOffset, int cOffset)
         {
             int cw, ch;
             YCbCrSize(width, height, ratio, out cw, out ch);
-            this.YPixels = new byte[width * height];
-            this.CbPixels = new byte[cw * ch];
-            this.CrPixels = new byte[cw * ch];
+            this.YPixels = CleanPooler<byte>.RentCleanArray(width * height);
+            this.CbPixels = CleanPooler<byte>.RentCleanArray(cw * ch);
+            this.CrPixels = CleanPooler<byte>.RentCleanArray(cw * ch);
             this.Ratio = ratio;
+            this.YOffset = yOffset;
+            this.COffset = cOffset;
             this.YStride = width;
             this.CStride = cw;
             this.X = 0;
@@ -41,8 +44,10 @@ namespace ImageSharp.Formats.Jpg
         /// <summary>
         /// Prevents a default instance of the <see cref="YCbCrImage"/> class from being created.
         /// </summary>
-        private YCbCrImage()
+        private YCbCrImage(int yOffset, int cOffset)
         {
+            this.YOffset = yOffset;
+            this.COffset = cOffset;
         }
         
         /// <summary>
@@ -84,38 +89,38 @@ namespace ImageSharp.Formats.Jpg
         /// <summary>
         /// Gets or sets the luminance components channel.
         /// </summary>
-        public byte[] YPixels { get; private set; }
+        public byte[] YPixels { get; }
 
         /// <summary>
         /// Gets or sets the blue chroma components channel.
         /// </summary>
-        public byte[] CbPixels { get; private set; }
+        public byte[] CbPixels { get; }
 
         /// <summary>
         /// Gets or sets the red chroma components channel.
         /// </summary>
-        public byte[] CrPixels { get; private set; }
+        public byte[] CrPixels { get; }
 
         /// <summary>
         /// Gets or sets the Y slice index delta between vertically adjacent pixels.
         /// </summary>
-        public int YStride { get; private set; }
+        public int YStride { get; }
 
         /// <summary>
         /// Gets or sets the red and blue chroma slice index delta between vertically adjacent pixels
         /// that map to separate chroma samples.
         /// </summary>
-        public int CStride { get; private set; }
+        public int CStride { get; }
 
         /// <summary>
         /// Gets or sets the index of the first luminance element.
         /// </summary>
-        public int YOffset { get; private set; }
+        public int YOffset { get; }
 
         /// <summary>
         /// Gets or sets the index of the first element of red or blue chroma.
         /// </summary>
-        public int COffset { get; private set; }
+        public int COffset { get; }
 
         /// <summary>
         /// Gets or sets the horizontal position.
@@ -132,32 +137,6 @@ namespace ImageSharp.Formats.Jpg
         /// </summary>
         public YCbCrSubsampleRatio Ratio { get; set; }
 
-        ///// <summary>
-        ///// Gets an image made up of a subset of the originals pixels.
-        ///// </summary>
-        ///// <param name="x">The x-coordinate of the image.</param>
-        ///// <param name="y">The y-coordinate of the image.</param>
-        ///// <param name="width">The width.</param>
-        ///// <param name="height">The height.</param>
-        ///// <returns>
-        ///// The <see cref="YCbCrImage"/>.
-        ///// </returns>
-        //public YCbCrImage Subimage(int x, int y, int width, int height)
-        //{
-        //    YCbCrImage ret = new YCbCrImage
-        //    {
-        //        YPixels = this.YPixels,
-        //        CbPixels = this.CbPixels,
-        //        CrPixels = this.CrPixels,
-        //        Ratio = this.Ratio,
-        //        YStride = this.YStride,
-        //        CStride = this.CStride,
-        //        YOffset = (y * this.YStride) + x,
-        //        COffset = (y * this.CStride) + x
-        //    };
-        //    return ret;
-        //}
-        
         /// <summary>
         /// Returns the offset of the first luminance component at the given row
         /// </summary>
@@ -236,5 +215,12 @@ namespace ImageSharp.Formats.Jpg
                     break;
             }
         }
+
+        public void Dispose()
+        {
+            CleanPooler<byte>.ReturnArray(this.YPixels);
+            CleanPooler<byte>.ReturnArray(this.CrPixels);
+            CleanPooler<byte>.ReturnArray(this.CbPixels);
+        }
     }
 }

src/ImageSharp/Formats/Jpg/JpegDecoderCore.cs

@@ -472,6 +472,7 @@ namespace ImageSharp.Formats
                 this.huffmanTrees[i].Dispose();
             }
 
+            this.ycbcrImage?.Dispose();
             this.bytes.Dispose();
             this.grayImage.ReturnPooled();
             this.blackImage.ReturnPooled();
@@ -2059,8 +2060,8 @@ namespace ImageSharp.Formats
             
             if (this.componentCount == 1)
             {
-                JpegPixelArea gray = JpegPixelArea.CreatePooled(8 * mxx, 8 * myy);
-                this.grayImage = gray.Subimage(0, 0, this.imageWidth, this.imageHeight);
+                this.grayImage = JpegPixelArea.CreatePooled(8 * mxx, 8 * myy);
+                //this.grayImage = gray.Subimage(0, 0, this.imageWidth, this.imageHeight);
             }
             else
             {
@@ -2092,9 +2093,8 @@ namespace ImageSharp.Formats
                         break;
                 }
 
-                this.ycbcrImage = new YCbCrImage(8 * h0 * mxx, 8 * v0 * myy, ratio);
-                //this.ycbcrImage = ycbcr.Subimage(0, 0, this.imageWidth, this.imageHeight);
-
+                this.ycbcrImage = new YCbCrImage(8 * h0 * mxx, 8 * v0 * myy, ratio, 0, 0);
+                
                 if (this.componentCount == 4)
                 {
                     int h3 = this.componentArray[3].HorizontalFactor;

src/ImageSharp/Formats/Jpg/Utils/ArrayPoolManager.cs → src/ImageSharp/Formats/Jpg/Utils/CleanPooler.cs

@@ -2,7 +2,7 @@
 {
     using System.Buffers;
 
-    internal class ArrayPoolManager<T>
+    internal class CleanPooler<T>
     {
         private static readonly ArrayPool<T> Pool = ArrayPool<T>.Create();