comment cleanup & BlockQuad

src/ImageSharp/Formats/Jpg/Components/BlockQuad.cs

@@ -0,0 +1,18 @@
+// <copyright file="BlockQuad.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+namespace ImageSharp.Formats.Jpg.Components
+{
+    /// <summary>
+    /// Poor man's stackalloc: Contains a value-type <see cref="float"/> buffer sized for 4 <see cref="Block8x8F"/> instances.
+    /// Useful for decoder/encoder operations allocating a block for each Jpeg component.
+    /// </summary>
+    internal unsafe struct BlockQuad
+    {
+        /// <summary>
+        /// The value-type <see cref="float"/> buffer sized for 4 <see cref="Block8x8F"/> instances.
+        /// </summary>
+        public fixed float Data[4 * Block8x8F.ScalarCount];
+    }
+}

src/ImageSharp/Formats/Jpg/JpegEncoderCore.cs

@@ -11,6 +11,7 @@ namespace ImageSharp.Formats
     using System.Runtime.CompilerServices;
 
     using ImageSharp.Formats.Jpg;
+    using ImageSharp.Formats.Jpg.Components;
 
     /// <summary>
     /// Image encoder for writing an image to a stream as a jpeg.
@@ -150,21 +151,11 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Encode writes the image to the jpeg baseline format with the given options.
         /// </summary>
-        /// <typeparam name="TColor">
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// The pixel format.
+        /// <param name="image">The image to write from.</param>
-        /// </typeparam>
+        /// <param name="stream">The stream to write to.</param>
-        /// <param name="image">
+        /// <param name="quality">The quality.</param>
-        /// The image to write from.
+        /// <param name="sample">The subsampling mode.</param>
-        /// </param>
-        /// <param name="stream">
-        /// The stream to write to.
-        /// </param>
-        /// <param name="quality">
-        /// The quality.
-        /// </param>
-        /// <param name="sample">
-        /// The subsampling mode.
-        /// </param>
         public void Encode<TColor>(Image<TColor> image, Stream stream, int quality, JpegSubsample sample)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
@@ -258,30 +249,14 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Converts the 8x8 region of the image whose top-left corner is x,y to its YCbCr values.
         /// </summary>
-        /// <typeparam name="TColor">
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// The pixel format.
+        /// <param name="pixels">The pixel accessor.</param>
-        /// </typeparam>
+        /// <param name="x">The x-position within the image.</param>
-        /// <param name="pixels">
+        /// <param name="y">The y-position within the image.</param>
-        /// The pixel accessor.
+        /// <param name="yBlock">The luminance block.</param>
-        /// </param>
+        /// <param name="cbBlock">The red chroma block.</param>
-        /// <param name="x">
+        /// <param name="crBlock">The blue chroma block.</param>
-        /// The x-position within the image.
+        /// <param name="rgbBytes">Temporal <see cref="PixelArea{TColor}"/> provided by the caller</param>
-        /// </param>
-        /// <param name="y">
-        /// The y-position within the image.
-        /// </param>
-        /// <param name="yBlock">
-        /// The luminance block.
-        /// </param>
-        /// <param name="cbBlock">
-        /// The red chroma block.
-        /// </param>
-        /// <param name="crBlock">
-        /// The blue chroma block.
-        /// </param>
-        /// <param name="rgbBytes">
-        /// Temporal <see cref="PixelArea{TColor}"/> provided by the caller
-        /// </param>
         private static void ToYCbCr<TColor>(
             PixelAccessor<TColor> pixels,
             int x,
@@ -332,12 +307,8 @@ namespace ImageSharp.Formats
         /// </example>
         /// .
         /// </summary>
-        /// <param name="bits">
+        /// <param name="bits">The packed bits.</param>
-        /// The packed bits.
+        /// <param name="count">The number of bits</param>
-        /// </param>
-        /// <param name="count">
-        /// The number of bits
-        /// </param>
         private void Emit(uint bits, uint count)
         {
             count += this.bitCount;
@@ -375,12 +346,8 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Emits the given value with the given Huffman encoder.
         /// </summary>
-        /// <param name="index">
+        /// <param name="index">The index of the Huffman encoder</param>
-        /// The index of the Huffman encoder
+        /// <param name="value">The value to encode.</param>
-        /// </param>
-        /// <param name="value">
-        /// The value to encode.
-        /// </param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void EmitHuff(HuffIndex index, int value)
         {
@@ -391,15 +358,9 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Emits a run of runLength copies of value encoded with the given Huffman encoder.
         /// </summary>
-        /// <param name="index">
+        /// <param name="index">The index of the Huffman encoder</param>
-        /// The index of the Huffman encoder
+        /// <param name="runLength">The number of copies to encode.</param>
-        /// </param>
+        /// <param name="value">The value to encode.</param>
-        /// <param name="runLength">
-        /// The number of copies to encode.
-        /// </param>
-        /// <param name="value">
-        /// The value to encode.
-        /// </param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void EmitHuffRLE(HuffIndex index, int runLength, int value)
         {
@@ -431,12 +392,8 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Encodes the image with no subsampling.
         /// </summary>
-        /// <typeparam name="TColor">
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// The pixel format.
+        /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// </typeparam>
-        /// <param name="pixels">
-        /// The pixel accessor providing access to the image pixels.
-        /// </param>
         private void Encode444<TColor>(PixelAccessor<TColor> pixels)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
@@ -496,12 +453,8 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the application header containing the JFIF identifier plus extra data.
         /// </summary>
-        /// <param name="horizontalResolution">
+        /// <param name="horizontalResolution">The resolution of the image in the x- direction.</param>
-        /// The resolution of the image in the x- direction.
+        /// <param name="verticalResolution">The resolution of the image in the y- direction.</param>
-        /// </param>
-        /// <param name="verticalResolution">
-        /// The resolution of the image in the y- direction.
-        /// </param>
         private void WriteApplicationHeader(short horizontalResolution, short verticalResolution)
         {
             // Write the start of image marker. Markers are always prefixed with with 0xff.
@@ -542,27 +495,13 @@ namespace ImageSharp.Formats
         /// returning the post-quantized DC value of the DCT-transformed block.
         /// The block is in natural (not zig-zag) order.
         /// </summary>
-        /// <param name="index">
+        /// <param name="index">The quantization table index.</param>
-        /// The quantization table index.
+        /// <param name="prevDC">The previous DC value.</param>
-        /// </param>
+        /// <param name="src">Source block</param>
-        /// <param name="prevDC">
+        /// <param name="tempDest">Temporal block to be used as FDCT Destination</param>
-        /// The previous DC value.
+        /// <param name="temp2">Temporal block 2</param>
-        /// </param>
+        /// <param name="quant">Quantization table</param>
-        /// <param name="src">
+        /// <param name="unzigPtr">The 8x8 Unzig block ptr</param>
-        /// Source block
-        /// </param>
-        /// <param name="tempDest">
-        /// Temporal block to be used as FDCT Destination
-        /// </param>
-        /// <param name="temp2">
-        /// Temporal block 2
-        /// </param>
-        /// <param name="quant">
-        /// Quantization table
-        /// </param>
-        /// <param name="unzigPtr">
-        /// The 8x8 Unzig block ptr
-        /// </param>
         /// <returns>
         /// The <see cref="int"/>
         /// </returns>
@@ -622,9 +561,7 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the Define Huffman Table marker and tables.
         /// </summary>
-        /// <param name="componentCount">
+        /// <param name="componentCount">The number of components to write.</param>
-        /// The number of components to write.
-        /// </param>
         private void WriteDefineHuffmanTables(int componentCount)
         {
             // Table identifiers.
@@ -695,9 +632,7 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the EXIF profile.
         /// </summary>
-        /// <param name="exifProfile">
+        /// <param name="exifProfile">The exif profile.</param>
-        /// The exif profile.
-        /// </param>
         /// <exception cref="ImageFormatException">
         /// Thrown if the EXIF profile size exceeds the limit
         /// </exception>
@@ -729,12 +664,8 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the metadata profiles to the image.
         /// </summary>
-        /// <param name="image">
+        /// <param name="image">The image.</param>
-        /// The image.
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// </param>
-        /// <typeparam name="TColor">
-        /// The pixel format.
-        /// </typeparam>
         private void WriteProfiles<TColor>(Image<TColor> image)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
@@ -744,15 +675,9 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the Start Of Frame (Baseline) marker
         /// </summary>
-        /// <param name="width">
+        /// <param name="width">The width of the image</param>
-        /// The width of the image
+        /// <param name="height">The height of the image</param>
-        /// </param>
+        /// <param name="componentCount">The number of components in a pixel</param>
-        /// <param name="height">
-        /// The height of the image
-        /// </param>
-        /// <param name="componentCount">
-        /// The number of components in a pixel
-        /// </param>
         private void WriteStartOfFrame(int width, int height, int componentCount)
         {
             // "default" to 4:2:0
@@ -806,12 +731,8 @@ namespace ImageSharp.Formats
         /// <summary>
         /// Writes the StartOfScan marker.
         /// </summary>
-        /// <typeparam name="TColor">
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// The pixel format.
+        /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// </typeparam>
-        /// <param name="pixels">
-        /// The pixel accessor providing access to the image pixels.
-        /// </param>
         private void WriteStartOfScan<TColor>(PixelAccessor<TColor> pixels)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
@@ -833,28 +754,12 @@ namespace ImageSharp.Formats
             this.Emit(0x7f, 7);
         }
 
-#pragma warning disable SA1201 // MethodShouldNotFollowAStruct
-
-        /// <summary>
-        ///     Poor man's stackalloc for Encode420.
-        ///     This struct belongs to Encode420. Much easeier to understand code if they are close to each other. Why should I
-        ///     move it Up? :P
-        /// </summary>
-        private struct BlockQuad
-        {
-            public fixed float Data[4 * Block8x8F.ScalarCount];
-        }
-
         /// <summary>
         /// Encodes the image with subsampling. The Cb and Cr components are each subsampled
         /// at a factor of 2 both horizontally and vertically.
         /// </summary>
-        /// <typeparam name="TColor">
+        /// <typeparam name="TColor">The pixel format.</typeparam>
-        /// The pixel format.
+        /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// </typeparam>
-        /// <param name="pixels">
-        /// The pixel accessor providing access to the image pixels.
-        /// </param>
         private void Encode420<TColor>(PixelAccessor<TColor> pixels)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
@@ -923,17 +828,11 @@ namespace ImageSharp.Formats
             }
         }
 
-#pragma warning restore SA1201
-
         /// <summary>
         /// Writes the header for a marker with the given length.
         /// </summary>
-        /// <param name="marker">
+        /// <param name="marker">The marker to write.</param>
-        /// The marker to write.
+        /// <param name="length">The marker length.</param>
-        /// </param>
-        /// <param name="length">
-        /// The marker length.
-        /// </param>
         private void WriteMarkerHeader(byte marker, int length)
         {
             // Markers are always prefixed with with 0xff.