Merge pull request #1734 from SixLabors/bp/tiffjpegcompression

Adds support for Tiff's with jpeg compression

Author: JimBobSquarePants

src/ImageSharp/Formats/Jpeg/Components/Decoder/HuffmanScanDecoder.cs

@@ -38,10 +38,14 @@ internal class HuffmanScanDecoder
         /// </summary>
         private int restartInterval;
 
-        // How many mcu's are left to do.
+        /// <summary>
+        /// How many mcu's are left to do.
+        /// </summary>
         private int todo;
 
-        // The End-Of-Block countdown for ending the sequence prematurely when the remaining coefficients are zero.
+        /// <summary>
+        /// The End-Of-Block countdown for ending the sequence prematurely when the remaining coefficients are zero.
+        /// </summary>
         private int eobrun;
 
         /// <summary>
@@ -54,14 +58,16 @@ internal class HuffmanScanDecoder
         /// </summary>
         private readonly HuffmanTable[] acHuffmanTables;
 
-        // The unzig data.
+        /// <summary>
+        /// The unzig data.
+        /// </summary>
         private ZigZag dctZigZag;
 
         private HuffmanScanBuffer scanBuffer;
 
         private readonly SpectralConverter spectralConverter;
 
-        private CancellationToken cancellationToken;
+        private readonly CancellationToken cancellationToken;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="HuffmanScanDecoder"/> class.

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
+using SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder.ColorConverters;
+
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 {
     /// <summary>
@@ -30,5 +32,13 @@ internal abstract class SpectralConverter
         /// Actual stride height depends on the subsampling factor of the given component.
         /// </remarks>
         public abstract void ConvertStrideBaseline();
+
+        /// <summary>
+        /// Gets the color converter.
+        /// </summary>
+        /// <param name="frame">The jpeg frame with the color space to convert to.</param>
+        /// <param name="jpegData">The raw JPEG data.</param>
+        /// <returns>The color converter.</returns>
+        public virtual JpegColorConverter GetColorConverter(JpegFrame frame, IRawJpegData jpegData) => JpegColorConverter.GetConverter(jpegData.ColorSpace, frame.Precision);
     }
 }

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter{TPixel}.cs

@@ -11,12 +11,12 @@
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 {
-    internal sealed class SpectralConverter<TPixel> : SpectralConverter, IDisposable
+    internal class SpectralConverter<TPixel> : SpectralConverter, IDisposable
         where TPixel : unmanaged, IPixel<TPixel>
     {
         private readonly Configuration configuration;
 
-        private CancellationToken cancellationToken;
+        private readonly CancellationToken cancellationToken;
 
         private JpegComponentPostProcessor[] componentProcessors;
 
@@ -59,6 +59,7 @@ public Buffer2D<TPixel> PixelBuffer
             }
         }
 
+        /// <inheritdoc/>
         public override void InjectFrameData(JpegFrame frame, IRawJpegData jpegData)
         {
             MemoryAllocator allocator = this.configuration.MemoryAllocator;
@@ -85,9 +86,10 @@ public override void InjectFrameData(JpegFrame frame, IRawJpegData jpegData)
             this.rgbaBuffer = allocator.Allocate<Vector4>(frame.PixelWidth);
 
             // color converter from Rgba32 to TPixel
-            this.colorConverter = JpegColorConverter.GetConverter(jpegData.ColorSpace, frame.Precision);
+            this.colorConverter = this.GetColorConverter(frame, jpegData);
         }
 
+        /// <inheritdoc/>
         public override void ConvertStrideBaseline()
         {
             // Convert next pixel stride using single spectral `stride'

src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs

@@ -41,7 +41,7 @@ internal class HuffmanScanEncoder
         private int emitLen = 0;
 
         /// <summary>
-        /// Emmited bits 'micro buffer' before being transfered to the <see cref="emitBuffer"/>.
+        /// Emitted bits 'micro buffer' before being transferred to the <see cref="emitBuffer"/>.
         /// </summary>
         private int accumulatedBits;
 
@@ -58,18 +58,15 @@ internal class HuffmanScanEncoder
         /// </summary>
         private readonly Stream target;
 
-        public HuffmanScanEncoder(Stream outputStream)
-        {
-            this.target = outputStream;
-        }
+        public HuffmanScanEncoder(Stream outputStream) => this.target = outputStream;
 
         /// <summary>
         /// Encodes the image with no subsampling.
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee</param>
-        /// <param name="chrominanceQuantTable">Chrominance quantization table provided by the callee</param>
+        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee.</param>
+        /// <param name="chrominanceQuantTable">Chrominance quantization table provided by the callee.</param>
         /// <param name="cancellationToken">The token to monitor for cancellation.</param>
         public void Encode444<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuantTable, ref Block8x8F chrominanceQuantTable, CancellationToken cancellationToken)
             where TPixel : unmanaged, IPixel<TPixel>
@@ -128,8 +125,8 @@ public void Encode444<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuant
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee</param>
-        /// <param name="chrominanceQuantTable">Chrominance quantization table provided by the callee</param>
+        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee.</param>
+        /// <param name="chrominanceQuantTable">Chrominance quantization table provided by the callee.</param>
         /// <param name="cancellationToken">The token to monitor for cancellation.</param>
         public void Encode420<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuantTable, ref Block8x8F chrominanceQuantTable, CancellationToken cancellationToken)
             where TPixel : unmanaged, IPixel<TPixel>
@@ -196,7 +193,7 @@ public void Encode420<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuant
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
-        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee</param>
+        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee.</param>
         /// <param name="cancellationToken">The token to monitor for cancellation.</param>
         public void EncodeGrayscale<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuantTable, CancellationToken cancellationToken)
             where TPixel : unmanaged, IPixel<TPixel>
@@ -234,6 +231,64 @@ public void EncodeGrayscale<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanc
             this.FlushInternalBuffer();
         }
 
+        /// <summary>
+        /// Encodes the image with no subsampling and keeps the pixel data as Rgb24.
+        /// </summary>
+        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <param name="pixels">The pixel accessor providing access to the image pixels.</param>
+        /// <param name="luminanceQuantTable">Luminance quantization table provided by the callee.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation.</param>
+        public void EncodeRgb<TPixel>(Image<TPixel> pixels, ref Block8x8F luminanceQuantTable, CancellationToken cancellationToken)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            this.huffmanTables = HuffmanLut.TheHuffmanLut;
+
+            var unzig = ZigZag.CreateUnzigTable();
+
+            // ReSharper disable once InconsistentNaming
+            int prevDCR = 0, prevDCG = 0, prevDCB = 0;
+
+            ImageFrame<TPixel> frame = pixels.Frames.RootFrame;
+            Buffer2D<TPixel> pixelBuffer = frame.PixelBuffer;
+            RowOctet<TPixel> currentRows = default;
+
+            var pixelConverter = new RgbForwardConverter<TPixel>(frame);
+
+            for (int y = 0; y < pixels.Height; y += 8)
+            {
+                cancellationToken.ThrowIfCancellationRequested();
+                currentRows.Update(pixelBuffer, y);
+
+                for (int x = 0; x < pixels.Width; x += 8)
+                {
+                    pixelConverter.Convert(x, y, ref currentRows);
+
+                    prevDCR = this.WriteBlock(
+                        QuantIndex.Luminance,
+                        prevDCR,
+                        ref pixelConverter.R,
+                        ref luminanceQuantTable,
+                        ref unzig);
+
+                    prevDCG = this.WriteBlock(
+                        QuantIndex.Luminance,
+                        prevDCG,
+                        ref pixelConverter.G,
+                        ref luminanceQuantTable,
+                        ref unzig);
+
+                    prevDCB = this.WriteBlock(
+                        QuantIndex.Luminance,
+                        prevDCB,
+                        ref pixelConverter.B,
+                        ref luminanceQuantTable,
+                        ref unzig);
+                }
+            }
+
+            this.FlushInternalBuffer();
+        }
+
         /// <summary>
         /// Writes a block of pixel data using the given quantization table,
         /// returning the post-quantized DC value of the DCT-transformed block.
@@ -437,7 +492,7 @@ internal static int GetHuffmanEncodingLength(uint value)
             DebugGuard.IsTrue(value <= (1 << 16), "Huffman encoder is supposed to encode a value of 16bit size max");
 #if SUPPORTS_BITOPERATIONS
             // This should have been implemented as (BitOperations.Log2(value) + 1) as in non-intrinsic implementation
-            // But internal log2 is implementated like this: (31 - (int)Lzcnt.LeadingZeroCount(value))
+            // But internal log2 is implemented like this: (31 - (int)Lzcnt.LeadingZeroCount(value))
 
             // BitOperations.Log2 implementation also checks if input value is zero for the convention 0->0
             // Lzcnt would return 32 for input value of 0 - no need to check that with branching
@@ -449,7 +504,7 @@ internal static int GetHuffmanEncodingLength(uint value)
             // if 0 - return 0 in this case
             // else - return log2(value) + 1
             //
-            // Hack based on input value constaint:
+            // Hack based on input value constraint:
             // We know that input values are guaranteed to be maximum 16 bit large for huffman encoding
             // We can safely shift input value for one bit -> log2(value << 1)
             // Because of the 16 bit value constraint it won't overflow

src/ImageSharp/Formats/Jpeg/Components/Encoder/QuantIndex.cs

@@ -1,21 +1,21 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
 {
     /// <summary>
-    ///     Enumerates the quantization tables
+    /// Enumerates the quantization tables.
     /// </summary>
     internal enum QuantIndex
     {
         /// <summary>
-        ///     The luminance quantization table index
+        /// The luminance quantization table index.
         /// </summary>
         Luminance = 0,
 
         /// <summary>
-        ///     The chrominance quantization table index
+        /// The chrominance quantization table index.
         /// </summary>
         Chrominance = 1,
     }
-}
+}

src/ImageSharp/Formats/Jpeg/Components/Encoder/RgbForwardConverter{TPixel}.cs

@@ -0,0 +1,114 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
+{
+    /// <summary>
+    /// On-stack worker struct to convert TPixel -> Rgb24 of 8x8 pixel blocks.
+    /// </summary>
+    /// <typeparam name="TPixel">The pixel type to work on.</typeparam>
+    internal ref struct RgbForwardConverter<TPixel>
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        /// <summary>
+        /// Number of pixels processed per single <see cref="Convert(int, int, ref RowOctet{TPixel})"/> call
+        /// </summary>
+        private const int PixelsPerSample = 8 * 8;
+
+        /// <summary>
+        /// Total byte size of processed pixels converted from TPixel to <see cref="Rgb24"/>
+        /// </summary>
+        private const int RgbSpanByteSize = PixelsPerSample * 3;
+
+        /// <summary>
+        /// <see cref="Size"/> of sampling area from given frame pixel buffer.
+        /// </summary>
+        private static readonly Size SampleSize = new Size(8, 8);
+
+        /// <summary>
+        /// The Red component.
+        /// </summary>
+        public Block8x8F R;
+
+        /// <summary>
+        /// The Green component.
+        /// </summary>
+        public Block8x8F G;
+
+        /// <summary>
+        /// The Blue component.
+        /// </summary>
+        public Block8x8F B;
+
+        /// <summary>
+        /// Temporal 64-byte span to hold unconverted TPixel data.
+        /// </summary>
+        private readonly Span<TPixel> pixelSpan;
+
+        /// <summary>
+        /// Temporal 64-byte span to hold converted Rgb24 data.
+        /// </summary>
+        private readonly Span<Rgb24> rgbSpan;
+
+        /// <summary>
+        /// Sampled pixel buffer size.
+        /// </summary>
+        private readonly Size samplingAreaSize;
+
+        /// <summary>
+        /// <see cref="Configuration"/> for internal operations.
+        /// </summary>
+        private readonly Configuration config;
+
+        public RgbForwardConverter(ImageFrame<TPixel> frame)
+        {
+            this.R = default;
+            this.G = default;
+            this.B = default;
+
+            // temporal pixel buffers
+            this.pixelSpan = new TPixel[PixelsPerSample].AsSpan();
+            this.rgbSpan = MemoryMarshal.Cast<byte, Rgb24>(new byte[RgbSpanByteSize + RgbToYCbCrConverterVectorized.AvxCompatibilityPadding].AsSpan());
+
+            // frame data
+            this.samplingAreaSize = new Size(frame.Width, frame.Height);
+            this.config = frame.GetConfiguration();
+        }
+
+        /// <summary>
+        /// Converts a 8x8 image area inside 'pixels' at position (x, y) to Rgb24.
+        /// </summary>
+        public void Convert(int x, int y, ref RowOctet<TPixel> currentRows)
+        {
+            YCbCrForwardConverter<TPixel>.LoadAndStretchEdges(currentRows, this.pixelSpan, new Point(x, y), SampleSize, this.samplingAreaSize);
+
+            PixelOperations<TPixel>.Instance.ToRgb24(this.config, this.pixelSpan, this.rgbSpan);
+
+            ref Block8x8F redBlock = ref this.R;
+            ref Block8x8F greenBlock = ref this.G;
+            ref Block8x8F blueBlock = ref this.B;
+
+            CopyToBlock(this.rgbSpan, ref redBlock, ref greenBlock, ref blueBlock);
+        }
+
+        private static void CopyToBlock(Span<Rgb24> rgbSpan, ref Block8x8F redBlock, ref Block8x8F greenBlock, ref Block8x8F blueBlock)
+        {
+            ref Rgb24 rgbStart = ref MemoryMarshal.GetReference(rgbSpan);
+
+            for (int i = 0; i < Block8x8F.Size; i++)
+            {
+                Rgb24 c = Unsafe.Add(ref rgbStart, i);
+
+                redBlock[i] = c.R;
+                greenBlock[i] = c.G;
+                blueBlock[i] = c.B;
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Jpeg/Components/Encoder/YCbCrForwardConverter420{TPixel}.cs

@@ -58,22 +58,22 @@ internal ref struct YCbCrForwardConverter420<TPixel>
         /// <summary>
         /// Temporal 16x8 block to hold TPixel data
         /// </summary>
-        private Span<TPixel> pixelSpan;
+        private readonly Span<TPixel> pixelSpan;
 
         /// <summary>
         /// Temporal RGB block
         /// </summary>
-        private Span<Rgb24> rgbSpan;
+        private readonly Span<Rgb24> rgbSpan;
 
         /// <summary>
         /// Sampled pixel buffer size
         /// </summary>
-        private Size samplingAreaSize;
+        private readonly Size samplingAreaSize;
 
         /// <summary>
         /// <see cref="Configuration"/> for internal operations
         /// </summary>
-        private Configuration config;
+        private readonly Configuration config;
 
         public YCbCrForwardConverter420(ImageFrame<TPixel> frame)
         {