Add support for decompressing huffman encoded tiffs

src/ImageSharp/Formats/Tiff/Compression/T4BitReader.cs

@@ -61,6 +61,8 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
         /// </summary>
         private bool isStartOfRow;
 
+        private readonly bool isModifiedHuffmanRle;
+
         private readonly int dataLength;
 
         private const int MinCodeLength = 2;
@@ -223,11 +225,13 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
         /// <param name="input">The compressed input stream.</param>
         /// <param name="bytesToRead">The number of bytes to read from the stream.</param>
         /// <param name="allocator">The memory allocator.</param>
-        public T4BitReader(Stream input, int bytesToRead, MemoryAllocator allocator)
+        /// <param name="isModifiedHuffman">Indicates, if its the modified huffman code variation.</param>
+        public T4BitReader(Stream input, int bytesToRead, MemoryAllocator allocator, bool isModifiedHuffman = false)
         {
             this.Data = allocator.Allocate<byte>(bytesToRead);
             this.ReadImageDataFromStream(input, bytesToRead, allocator);
 
+            this.isModifiedHuffmanRle = isModifiedHuffman;
             this.dataLength = bytesToRead;
             this.bitsRead = 0;
             this.value = 0;
@@ -302,7 +306,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
 
             this.Reset();
 
-            if (this.isFirstScanLine)
+            if (this.isFirstScanLine && !this.isModifiedHuffmanRle)
             {
                 // We expect an EOL before the first data.
                 this.value = this.ReadValue(12);
@@ -372,9 +376,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
 
                 if (this.IsEndOfScanLine)
                 {
-                    // Each new row starts with a white run.
+                    this.StartNewRow();
-                    this.isWhiteRun = true;
-                    this.isStartOfRow = true;
                 }
             }
             while (!this.IsEndOfScanLine);
@@ -382,6 +384,25 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
             this.isFirstScanLine = false;
         }
 
+        public void StartNewRow()
+        {
+            // Each new row starts with a white run.
+            this.isWhiteRun = true;
+            this.isStartOfRow = true;
+            this.terminationCodeFound = false;
+
+            if (this.isModifiedHuffmanRle)
+            {
+                int pad = 8 - (this.bitsRead % 8);
+                if (pad != 8)
+                {
+                    // Skip padding bits, move to next byte.
+                    this.position++;
+                    this.bitsRead = 0;
+                }
+            }
+        }
+
         /// <inheritdoc/>
         public void Dispose()
         {
@@ -601,6 +622,14 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
 
                 case 12:
                 {
+                    if (this.isModifiedHuffmanRle)
+                    {
+                        if (this.value == 1)
+                        {
+                            return true;
+                        }
+                    }
+
                     return WhiteLen12MakeupCodes.ContainsKey(this.value);
                 }
             }
@@ -619,6 +648,14 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
 
                 case 11:
                 {
+                    if (this.isModifiedHuffmanRle)
+                    {
+                        if (this.value == 0)
+                        {
+                            return true;
+                        }
+                    }
+
                     return BlackLen11MakeupCodes.ContainsKey(this.value);
                 }
 

src/ImageSharp/Formats/Tiff/Compression/T4TiffCompression.cs

@@ -17,8 +17,9 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
         /// </summary>
         /// <param name="allocator">The memory allocator.</param>
         /// <param name="photometricInterpretation">The photometric interpretation.</param>
-        public T4TiffCompression(MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation)
+        /// <param name="width">The image width.</param>
-            : base(allocator, photometricInterpretation)
+        public T4TiffCompression(MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation, int width)
+            : base(allocator, photometricInterpretation, width)
         {
         }
 
@@ -63,7 +64,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
             }
         }
 
-        private void WriteBits(Span<byte> buffer, int pos, uint count, int value)
+        protected void WriteBits(Span<byte> buffer, int pos, uint count, int value)
         {
             int bitPos = pos % 8;
             int bufferPos = pos / 8;
@@ -83,7 +84,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression
             }
         }
 
-        private void WriteBit(Span<byte> buffer, int bufferPos, int bitPos, int value)
+        protected void WriteBit(Span<byte> buffer, int bufferPos, int bitPos, int value)
         {
             buffer[bufferPos] |= (byte)(value << (7 - bitPos));
         }

src/ImageSharp/Formats/Tiff/Compression/TiffBaseCompression.cs

@@ -16,18 +16,23 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
         private TiffPhotometricInterpretation photometricInterpretation;
 
+        private int width;
+
         public TiffBaseCompression(MemoryAllocator allocator) => this.allocator = allocator;
 
-        public TiffBaseCompression(MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation)
+        public TiffBaseCompression(MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation, int width)
         {
             this.allocator = allocator;
             this.photometricInterpretation = photometricInterpretation;
+            this.width = width;
         }
 
         protected MemoryAllocator Allocator => this.allocator;
 
         protected TiffPhotometricInterpretation PhotometricInterpretation => this.photometricInterpretation;
 
+        protected int Width => this.width;
+
         /// <summary>
         /// Decompresses image data into the supplied buffer.
         /// </summary>

src/ImageSharp/Formats/Tiff/Compression/TiffCompressionFactory.cs

@@ -8,7 +8,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 {
     internal static class TiffCompressionFactory
     {
-        public static TiffBaseCompression Create(TiffCompressionType compressionType, MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation)
+        public static TiffBaseCompression Create(TiffCompressionType compressionType, MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation, int width)
         {
             switch (compressionType)
             {
@@ -21,7 +21,9 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                 case TiffCompressionType.Lzw:
                     return new LzwTiffCompression(allocator);
                 case TiffCompressionType.T4:
-                    return new T4TiffCompression(allocator, photometricInterpretation);
+                    return new T4TiffCompression(allocator, photometricInterpretation, width);
+                case TiffCompressionType.HuffmanRle:
+                    return new TiffModifiedHuffmanCompression(allocator, photometricInterpretation, width);
                 default:
                     throw TiffThrowHelper.NotSupportedCompression(nameof(compressionType));
             }

src/ImageSharp/Formats/Tiff/Compression/TiffCompressionType.cs

@@ -32,5 +32,10 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         /// Image data is compressed using T4-encoding: CCITT T.4.
         /// </summary>
         T4 = 4,
+
+        /// <summary>
+        /// Image data is compressed using modified huffman compression.
+        /// </summary>
+        HuffmanRle = 5,
     }
 }

src/ImageSharp/Formats/Tiff/Compression/TiffModifiedHuffmanCompression.cs

@@ -0,0 +1,72 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.IO;
+using SixLabors.ImageSharp.Memory;
+
+namespace SixLabors.ImageSharp.Formats.Tiff.Compression
+{
+    /// <summary>
+    /// Class to handle cases where TIFF image data is compressed using Modified Huffman Compression.
+    /// </summary>
+    internal class TiffModifiedHuffmanCompression : T4TiffCompression
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TiffModifiedHuffmanCompression" /> class.
+        /// </summary>
+        /// <param name="allocator">The memory allocator.</param>
+        /// <param name="photometricInterpretation">The photometric interpretation.</param>
+        /// <param name="width">The image width.</param>
+        public TiffModifiedHuffmanCompression(MemoryAllocator allocator, TiffPhotometricInterpretation photometricInterpretation, int width)
+            : base(allocator, photometricInterpretation, width)
+        {
+        }
+
+        /// <inheritdoc/>
+        public override void Decompress(Stream stream, int byteCount, Span<byte> buffer)
+        {
+            bool isWhiteZero = this.PhotometricInterpretation == TiffPhotometricInterpretation.WhiteIsZero;
+            int whiteValue = isWhiteZero ? 0 : 1;
+            int blackValue = isWhiteZero ? 1 : 0;
+
+            using var bitReader = new T4BitReader(stream, byteCount, this.Allocator, isModifiedHuffman: true);
+
+            uint bitsWritten = 0;
+            uint pixelsWritten = 0;
+            while (bitReader.HasMoreData)
+            {
+                bitReader.ReadNextRun();
+
+                if (bitReader.RunLength > 0)
+                {
+                    if (bitReader.IsWhiteRun)
+                    {
+                        this.WriteBits(buffer, (int)bitsWritten, bitReader.RunLength, whiteValue);
+                        bitsWritten += bitReader.RunLength;
+                        pixelsWritten += bitReader.RunLength;
+                    }
+                    else
+                    {
+                        this.WriteBits(buffer, (int)bitsWritten, bitReader.RunLength, blackValue);
+                        bitsWritten += bitReader.RunLength;
+                        pixelsWritten += bitReader.RunLength;
+                    }
+                }
+
+                if (pixelsWritten % this.Width == 0)
+                {
+                    bitReader.StartNewRow();
+
+                    // Write padding bytes, if necessary.
+                    uint pad = 8 - (bitsWritten % 8);
+                    if (pad != 8)
+                    {
+                        this.WriteBits(buffer, (int)bitsWritten, pad, 0);
+                        bitsWritten += pad;
+                    }
+                }
+            }
+        }
+    }
+}

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -210,11 +210,11 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
             if (this.PlanarConfiguration == TiffPlanarConfiguration.Planar)
             {
-                this.DecodeStripsPlanar(frame, rowsPerStrip, stripOffsets, stripByteCounts);
+                this.DecodeStripsPlanar(frame, rowsPerStrip, stripOffsets, stripByteCounts, width);
             }
             else
             {
-                this.DecodeStripsChunky(frame, rowsPerStrip, stripOffsets, stripByteCounts);
+                this.DecodeStripsChunky(frame, rowsPerStrip, stripOffsets, stripByteCounts, width);
             }
 
             return frame;
@@ -258,7 +258,8 @@ namespace SixLabors.ImageSharp.Formats.Tiff
         /// <param name="rowsPerStrip">The number of rows per strip of data.</param>
         /// <param name="stripOffsets">An array of byte offsets to each strip in the image.</param>
         /// <param name="stripByteCounts">An array of the size of each strip (in bytes).</param>
-        private void DecodeStripsPlanar<TPixel>(ImageFrame<TPixel> frame, int rowsPerStrip, uint[] stripOffsets, uint[] stripByteCounts)
+        /// <param name="width">The image width.</param>
+        private void DecodeStripsPlanar<TPixel>(ImageFrame<TPixel> frame, int rowsPerStrip, uint[] stripOffsets, uint[] stripByteCounts, int width)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             int stripsPerPixel = this.BitsPerSample.Length;
@@ -276,7 +277,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                     stripBuffers[stripIndex] = this.memoryAllocator.AllocateManagedByteBuffer(uncompressedStripSize);
                 }
 
-                TiffBaseCompression decompressor = TiffCompressionFactory.Create(this.CompressionType, this.memoryAllocator, this.PhotometricInterpretation);
+                TiffBaseCompression decompressor = TiffCompressionFactory.Create(this.CompressionType, this.memoryAllocator, this.PhotometricInterpretation, width);
 
                 RgbPlanarTiffColor<TPixel> colorDecoder = TiffColorDecoderFactory<TPixel>.CreatePlanar(this.ColorType, this.BitsPerSample, this.ColorMap);
 
@@ -304,7 +305,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
             }
         }
 
-        private void DecodeStripsChunky<TPixel>(ImageFrame<TPixel> frame, int rowsPerStrip, uint[] stripOffsets, uint[] stripByteCounts)
+        private void DecodeStripsChunky<TPixel>(ImageFrame<TPixel> frame, int rowsPerStrip, uint[] stripOffsets, uint[] stripByteCounts, int width)
            where TPixel : unmanaged, IPixel<TPixel>
         {
             int uncompressedStripSize = this.CalculateStripBufferSize(frame.Width, rowsPerStrip);
@@ -313,7 +314,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff
 
             Buffer2D<TPixel> pixels = frame.PixelBuffer;
 
-            TiffBaseCompression decompressor = TiffCompressionFactory.Create(this.CompressionType, this.memoryAllocator, this.PhotometricInterpretation);
+            TiffBaseCompression decompressor = TiffCompressionFactory.Create(this.CompressionType, this.memoryAllocator, this.PhotometricInterpretation, width);
 
             TiffBaseColorDecoder<TPixel> colorDecoder = TiffColorDecoderFactory<TPixel>.Create(this.ColorType, this.BitsPerSample, this.ColorMap);
 

src/ImageSharp/Formats/Tiff/TiffDecoderHelpers.cs

@@ -352,6 +352,12 @@ namespace SixLabors.ImageSharp.Formats.Tiff
                     break;
                 }
 
+                case TiffCompression.Ccitt1D:
+                {
+                    options.CompressionType = TiffCompressionType.HuffmanRle;
+                    break;
+                }
+
                 default:
                 {
                     TiffThrowHelper.ThrowNotSupported("The specified TIFF compression format is not supported: " + compression);

tests/ImageSharp.Tests/TestImages.cs

@@ -512,6 +512,7 @@ namespace SixLabors.ImageSharp.Tests
             public const string Calliphora_RgbPackbits = "Tiff/Calliphora_rgb_packbits.tiff";
             public const string Calliphora_RgbUncompressed = "Tiff/Calliphora_rgb_uncompressed.tiff";
             public const string Calliphora_Fax3Compressed = "Tiff/Calliphora_ccitt_fax3.tif";
+            public const string Calliphora_HuffmanCompressed = "Tiff/Calliphora_huffman_rle.tif";
 
             public const string CcittFax3AllTermCodes = "Tiff/ccitt_fax3_all_terminating_codes.tif";
             public const string CcittFax3AllMakupCodes = "Tiff/ccitt_fax3_all_makeupcodes_codes.tif";
@@ -545,7 +546,7 @@ namespace SixLabors.ImageSharp.Tests
 
             public const string SampleMetadata = "Tiff/metadata_sample.tiff";
 
-            public static readonly string[] All = { Calliphora_GrayscaleUncompressed, Calliphora_PaletteUncompressed, /*Calliphora_RgbDeflate_Predictor, Calliphora_RgbLzwe_Predictor, */ Calliphora_RgbPackbits, Calliphora_RgbUncompressed, Calliphora_Fax3Compressed, CcittFax3AllTermCodes, CcittFax3AllMakupCodes, GrayscaleDeflateMultistrip, GrayscaleUncompressed, PaletteDeflateMultistrip, PaletteUncompressed, /*RgbDeflate_Predictor,*/ RgbDeflateMultistrip, /*RgbJpeg,*/ /*RgbLzw_Predictor, RgbLzwMultistrip_Predictor,*/ RgbLzw_NoPredictor_Multistrip, RgbLzw_NoPredictor_Multistrip_Motorola, RgbLzw_NoPredictor_Singlestrip_Motorola, RgbPackbits, RgbPackbitsMultistrip, RgbUncompressed, /* MultiframeLzw_Predictor, MultiFrameDifferentVariants, SampleMetadata,*/ SmallRgbDeflate, SmallRgbLzw, };
+            public static readonly string[] All = { Calliphora_GrayscaleUncompressed, Calliphora_PaletteUncompressed, /*Calliphora_RgbDeflate_Predictor, Calliphora_RgbLzwe_Predictor, */ Calliphora_RgbPackbits, Calliphora_RgbUncompressed, Calliphora_HuffmanCompressed, Calliphora_Fax3Compressed, CcittFax3AllTermCodes, CcittFax3AllMakupCodes, GrayscaleDeflateMultistrip, GrayscaleUncompressed, PaletteDeflateMultistrip, PaletteUncompressed, /*RgbDeflate_Predictor,*/ RgbDeflateMultistrip, /*RgbJpeg,*/ /*RgbLzw_Predictor, RgbLzwMultistrip_Predictor,*/ RgbLzw_NoPredictor_Multistrip, RgbLzw_NoPredictor_Multistrip_Motorola, RgbLzw_NoPredictor_Singlestrip_Motorola, RgbPackbits, RgbPackbitsMultistrip, RgbUncompressed, /* MultiframeLzw_Predictor, MultiFrameDifferentVariants, SampleMetadata,*/ SmallRgbDeflate, SmallRgbLzw, };
 
             public static readonly string[] Multiframes = { MultiframeDeflateWithPreview /*MultiframeLzw_Predictor, MultiFrameDifferentSize, MultiframeDifferentSizeTiled, MultiFrameDifferentVariants,*/ };
 

tests/Images/Input/Tiff/Calliphora_huffman_rle.tif

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1a4f687de9925863b1c9f32f53b6c05fb121f9d7b02ff5869113c4745433f10d
+size 124644