/// <inheritdoc/>
public Image <TPixel> Decode <TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
where TPixel : unmanaged, IPixel <TPixel>
{
this.inputStream = stream;
var reader = new DirectoryReader(stream);
IEnumerable <ExifProfile> directories = reader.Read();
this.byteOrder = reader.ByteOrder;
var frames = new List <ImageFrame <TPixel> >();
foreach (ExifProfile ifd in directories)
{
cancellationToken.ThrowIfCancellationRequested();
ImageFrame <TPixel> frame = this.DecodeFrame <TPixel>(ifd, cancellationToken);
frames.Add(frame);
}
ImageMetadata metadata = TiffDecoderMetadataCreator.Create(frames, this.ignoreMetadata, reader.ByteOrder);
// TODO: Tiff frames can have different sizes
ImageFrame <TPixel> root = frames[0];
this.Dimensions = root.Size();
foreach (ImageFrame <TPixel> frame in frames)
{
if (frame.Size() != root.Size())
{
TiffThrowHelper.ThrowNotSupported("Images with different sizes are not supported");
}
}
return(new Image <TPixel>(this.Configuration, metadata, frames));
}
/// <summary>
/// Gets the height of the image frame.
/// </summary>
/// <param name="exifProfile">The image frame exif profile.</param>
/// <returns>The image height.</returns>
private static int GetImageHeight(ExifProfile exifProfile)
{
IExifValue <Number> height = exifProfile.GetValue(ExifTag.ImageLength);
if (height == null)
{
TiffThrowHelper.ThrowImageFormatException("The TIFF image frame is missing the ImageLength");
}
return((int)height.Value);
}
/// <summary>
/// Gets the width of the image frame.
/// </summary>
/// <param name="exifProfile">The image frame exif profile.</param>
/// <returns>The image width.</returns>
private static int GetImageWidth(ExifProfile exifProfile)
{
IExifValue <Number> width = exifProfile.GetValue(ExifTag.ImageWidth);
if (width == null)
{
TiffThrowHelper.ThrowImageFormatException("The TIFF image frame is missing the ImageWidth");
}
return((int)width.Value);
}
/// <summary>
/// Gets the width of the image frame.
/// </summary>
/// <param name="exifProfile">The image frame exif profile.</param>
/// <returns>The image width.</returns>
private static int GetImageWidth(ExifProfile exifProfile)
{
IExifValue <Number> width = exifProfile.GetValue(ExifTag.ImageWidth);
if (width == null)
{
TiffThrowHelper.ThrowImageFormatException("The TIFF image frame is missing the ImageWidth");
}
DebugGuard.MustBeLessThanOrEqualTo((ulong)width.Value, (ulong)int.MaxValue, nameof(ExifTag.ImageWidth));
return((int)width.Value);
}
public static ImageMetadata Create <TPixel>(List <ImageFrame <TPixel> > frames, bool ignoreMetadata, ByteOrder byteOrder, bool isBigTiff)
where TPixel : unmanaged, IPixel <TPixel>
{
if (frames.Count < 1)
{
TiffThrowHelper.ThrowImageFormatException("Expected at least one frame.");
}
ImageMetadata imageMetaData = Create(byteOrder, isBigTiff, frames[0].Metadata.ExifProfile);
if (!ignoreMetadata)
{
for (int i = 0; i < frames.Count; i++)
{
ImageFrame <TPixel> frame = frames[i];
ImageFrameMetadata frameMetaData = frame.Metadata;
if (TryGetIptc(frameMetaData.ExifProfile.Values, out byte[] iptcBytes))
private static ByteOrder ReadByteOrder(Stream stream)
{
Span <byte> headerBytes = stackalloc byte[2];
stream.Read(headerBytes);
if (headerBytes[0] == TiffConstants.ByteOrderLittleEndian && headerBytes[1] == TiffConstants.ByteOrderLittleEndian)
{
return(ByteOrder.LittleEndian);
}
if (headerBytes[0] == TiffConstants.ByteOrderBigEndian && headerBytes[1] == TiffConstants.ByteOrderBigEndian)
{
return(ByteOrder.BigEndian);
}
throw TiffThrowHelper.ThrowInvalidHeader();
}
private static void VerifyRequiredFieldsArePresent(ExifProfile exifProfile, TiffFrameMetadata frameMetadata)
{
if (exifProfile.GetValueInternal(ExifTag.StripOffsets) is null)
{
TiffThrowHelper.ThrowImageFormatException("StripOffsets are missing and are required for decoding the TIFF image!");
}
if (exifProfile.GetValueInternal(ExifTag.StripByteCounts) is null)
{
TiffThrowHelper.ThrowImageFormatException("StripByteCounts are missing and are required for decoding the TIFF image!");
}
if (frameMetadata.BitsPerPixel == null)
{
TiffThrowHelper.ThrowNotSupported("The TIFF BitsPerSample entry is missing which is required to decode the image!");
}
}
private IEnumerable <ExifProfile> ReadIfds(bool isBigTiff)
{
var readers = new List <EntryReader>();
while (this.nextIfdOffset != 0 && this.nextIfdOffset < (ulong)this.stream.Length)
{
var reader = new EntryReader(this.stream, this.ByteOrder, this.allocator);
reader.ReadTags(isBigTiff, this.nextIfdOffset);
if (reader.BigValues.Count > 0)
{
reader.BigValues.Sort((t1, t2) => t1.Offset.CompareTo(t2.Offset));
// this means that most likely all elements are placed before next IFD
if (reader.BigValues[0].Offset < reader.NextIfdOffset)
{
reader.ReadBigValues();
}
}
this.nextIfdOffset = reader.NextIfdOffset;
readers.Add(reader);
if (readers.Count >= DirectoryMax)
{
TiffThrowHelper.ThrowImageFormatException("TIFF image contains too many directories");
}
}
var list = new List <ExifProfile>(readers.Count);
foreach (EntryReader reader in readers)
{
reader.ReadBigValues();
var profile = new ExifProfile(reader.Values, reader.InvalidTags);
list.Add(profile);
}
return(list);
}
public static ImageMetadata Create<TPixel>(List<ImageFrame<TPixel>> frames, bool ignoreMetadata, ByteOrder byteOrder)
where TPixel : unmanaged, IPixel<TPixel>
{
if (frames.Count < 1)
{
TiffThrowHelper.ThrowImageFormatException("Expected at least one frame.");
}
var imageMetaData = new ImageMetadata();
ExifProfile exifProfileRootFrame = frames[0].Metadata.ExifProfile;
SetResolution(imageMetaData, exifProfileRootFrame);
TiffMetadata tiffMetadata = imageMetaData.GetTiffMetadata();
tiffMetadata.ByteOrder = byteOrder;
if (!ignoreMetadata)
{
for (int i = 0; i < frames.Count; i++)
{
ImageFrame<TPixel> frame = frames[i];
ImageFrameMetadata frameMetaData = frame.Metadata;
if (TryGetIptc(frameMetaData.ExifProfile.Values, out byte[] iptcBytes))
/// <summary>
/// Calculates the size (in bytes) for a pixel buffer using the determined color format.
/// </summary>
/// <param name="width">The width for the desired pixel buffer.</param>
/// <param name="height">The height for the desired pixel buffer.</param>
/// <param name="plane">The index of the plane for planar image configuration (or zero for chunky).</param>
/// <returns>The size (in bytes) of the required pixel buffer.</returns>
private int CalculateStripBufferSize(int width, int height, int plane = -1)
{
DebugGuard.MustBeLessThanOrEqualTo(plane, 3, nameof(plane));
int bitsPerPixel = 0;
if (this.PlanarConfiguration == TiffPlanarConfiguration.Chunky)
{
DebugGuard.IsTrue(plane == -1, "Expected Chunky planar.");
bitsPerPixel = this.BitsPerPixel;
}
else
{
switch (plane)
{
case 0:
bitsPerPixel = this.BitsPerSample.Channel0;
break;
case 1:
bitsPerPixel = this.BitsPerSample.Channel1;
break;
case 2:
bitsPerPixel = this.BitsPerSample.Channel2;
break;
default:
TiffThrowHelper.ThrowNotSupported("More then 3 color channels are not supported");
break;
}
}
int bytesPerRow = ((width * bitsPerPixel) + 7) / 8;
return(bytesPerRow * height);
}
private static void ParseCompression(this TiffDecoderCore options, TiffCompression?compression, ExifProfile exifProfile)
{
// Default 1 (No compression) https://www.awaresystems.be/imaging/tiff/tifftags/compression.html
switch (compression ?? TiffCompression.None)
{
case TiffCompression.None:
{
options.CompressionType = TiffDecoderCompressionType.None;
break;
}
case TiffCompression.PackBits:
{
options.CompressionType = TiffDecoderCompressionType.PackBits;
break;
}
case TiffCompression.Deflate:
case TiffCompression.OldDeflate:
{
options.CompressionType = TiffDecoderCompressionType.Deflate;
break;
}
case TiffCompression.Lzw:
{
options.CompressionType = TiffDecoderCompressionType.Lzw;
break;
}
case TiffCompression.CcittGroup3Fax:
{
options.CompressionType = TiffDecoderCompressionType.T4;
options.FaxCompressionOptions = exifProfile.GetValue(ExifTag.T4Options) != null ? (FaxCompressionOptions)exifProfile.GetValue(ExifTag.T4Options).Value : FaxCompressionOptions.None;
break;
}
case TiffCompression.CcittGroup4Fax:
{
options.CompressionType = TiffDecoderCompressionType.T6;
options.FaxCompressionOptions = exifProfile.GetValue(ExifTag.T4Options) != null ? (FaxCompressionOptions)exifProfile.GetValue(ExifTag.T4Options).Value : FaxCompressionOptions.None;
break;
}
case TiffCompression.Ccitt1D:
{
options.CompressionType = TiffDecoderCompressionType.HuffmanRle;
break;
}
case TiffCompression.Jpeg:
{
options.CompressionType = TiffDecoderCompressionType.Jpeg;
break;
}
default:
{
TiffThrowHelper.ThrowNotSupported($"The specified TIFF compression format '{compression}' is not supported");
break;
}
}
}
/// <summary>
/// Determines the TIFF compression and color types, and reads any associated parameters.
/// </summary>
/// <param name="options">The options.</param>
/// <param name="exifProfile">The exif profile of the frame to decode.</param>
/// <param name="frameMetadata">The IFD entries container to read the image format information for current frame.</param>
public static void VerifyAndParse(this TiffDecoderCore options, ExifProfile exifProfile, TiffFrameMetadata frameMetadata)
{
if (exifProfile.GetValueInternal(ExifTag.TileOffsets) is not null || exifProfile.GetValueInternal(ExifTag.TileByteCounts) is not null)
{
TiffThrowHelper.ThrowNotSupported("Tiled images are not supported.");
}
if (exifProfile.GetValueInternal(ExifTag.ExtraSamples) is not null)
{
TiffThrowHelper.ThrowNotSupported("ExtraSamples is not supported.");
}
TiffFillOrder fillOrder = (TiffFillOrder?)exifProfile.GetValue(ExifTag.FillOrder)?.Value ?? TiffFillOrder.MostSignificantBitFirst;
if (fillOrder == TiffFillOrder.LeastSignificantBitFirst && frameMetadata.BitsPerPixel != TiffBitsPerPixel.Bit1)
{
TiffThrowHelper.ThrowNotSupported("The lower-order bits of the byte FillOrder is only supported in combination with 1bit per pixel bicolor tiff's.");
}
if (frameMetadata.Predictor == TiffPredictor.FloatingPoint)
{
TiffThrowHelper.ThrowNotSupported("TIFF images with FloatingPoint horizontal predictor are not supported.");
}
TiffSampleFormat[] sampleFormats = exifProfile.GetValue(ExifTag.SampleFormat)?.Value?.Select(a => (TiffSampleFormat)a).ToArray();
TiffSampleFormat? sampleFormat = null;
if (sampleFormats != null)
{
sampleFormat = sampleFormats[0];
foreach (TiffSampleFormat format in sampleFormats)
{
if (format != TiffSampleFormat.UnsignedInteger && format != TiffSampleFormat.Float)
{
TiffThrowHelper.ThrowNotSupported("ImageSharp only supports the UnsignedInteger and Float SampleFormat.");
}
}
}
ushort[] ycbcrSubSampling = exifProfile.GetValue(ExifTag.YCbCrSubsampling)?.Value;
if (ycbcrSubSampling != null && ycbcrSubSampling.Length != 2)
{
TiffThrowHelper.ThrowImageFormatException("Invalid YCbCrSubsampling, expected 2 values.");
}
if (ycbcrSubSampling != null && ycbcrSubSampling[1] > ycbcrSubSampling[0])
{
TiffThrowHelper.ThrowImageFormatException("ChromaSubsampleVert shall always be less than or equal to ChromaSubsampleHoriz.");
}
if (exifProfile.GetValue(ExifTag.StripRowCounts)?.Value != null)
{
TiffThrowHelper.ThrowNotSupported("Variable-sized strips are not supported.");
}
VerifyRequiredFieldsArePresent(exifProfile, frameMetadata);
options.PlanarConfiguration = (TiffPlanarConfiguration?)exifProfile.GetValue(ExifTag.PlanarConfiguration)?.Value ?? DefaultPlanarConfiguration;
options.Predictor = frameMetadata.Predictor ?? TiffPredictor.None;
options.PhotometricInterpretation = frameMetadata.PhotometricInterpretation ?? TiffPhotometricInterpretation.Rgb;
options.SampleFormat = sampleFormat ?? TiffSampleFormat.UnsignedInteger;
options.BitsPerPixel = frameMetadata.BitsPerPixel != null ? (int)frameMetadata.BitsPerPixel.Value : (int)TiffBitsPerPixel.Bit24;
options.BitsPerSample = frameMetadata.BitsPerSample ?? new TiffBitsPerSample(0, 0, 0);
options.ReferenceBlackAndWhite = exifProfile.GetValue(ExifTag.ReferenceBlackWhite)?.Value;
options.YcbcrCoefficients = exifProfile.GetValue(ExifTag.YCbCrCoefficients)?.Value;
options.YcbcrSubSampling = exifProfile.GetValue(ExifTag.YCbCrSubsampling)?.Value;
options.FillOrder = fillOrder;
options.JpegTables = exifProfile.GetValue(ExifTag.JPEGTables)?.Value;
options.ParseColorType(exifProfile);
options.ParseCompression(frameMetadata.Compression, exifProfile);
}
private static void ParseColorType(this TiffDecoderCore options, ExifProfile exifProfile)
{
switch (options.PhotometricInterpretation)
{
case TiffPhotometricInterpretation.WhiteIsZero:
{
if (options.BitsPerSample.Channels != 1)
{
TiffThrowHelper.ThrowNotSupported("The number of samples in the TIFF BitsPerSample entry is not supported.");
}
ushort bitsPerChannel = options.BitsPerSample.Channel0;
if (bitsPerChannel > 32)
{
TiffThrowHelper.ThrowNotSupported("Bits per sample is not supported.");
}
switch (bitsPerChannel)
{
case 32:
{
if (options.SampleFormat == TiffSampleFormat.Float)
{
options.ColorType = TiffColorType.WhiteIsZero32Float;
return;
}
options.ColorType = TiffColorType.WhiteIsZero32;
break;
}
case 24:
{
options.ColorType = TiffColorType.WhiteIsZero24;
break;
}
case 16:
{
options.ColorType = TiffColorType.WhiteIsZero16;
break;
}
case 8:
{
options.ColorType = TiffColorType.WhiteIsZero8;
break;
}
case 4:
{
options.ColorType = TiffColorType.WhiteIsZero4;
break;
}
case 1:
{
options.ColorType = TiffColorType.WhiteIsZero1;
break;
}
default:
{
options.ColorType = TiffColorType.WhiteIsZero;
break;
}
}
break;
}
case TiffPhotometricInterpretation.BlackIsZero:
{
if (options.BitsPerSample.Channels != 1)
{
TiffThrowHelper.ThrowNotSupported("The number of samples in the TIFF BitsPerSample entry is not supported.");
}
ushort bitsPerChannel = options.BitsPerSample.Channel0;
if (bitsPerChannel > 32)
{
TiffThrowHelper.ThrowNotSupported("Bits per sample is not supported.");
}
switch (bitsPerChannel)
{
case 32:
{
if (options.SampleFormat == TiffSampleFormat.Float)
{
options.ColorType = TiffColorType.BlackIsZero32Float;
return;
}
options.ColorType = TiffColorType.BlackIsZero32;
break;
}
case 24:
{
options.ColorType = TiffColorType.BlackIsZero24;
break;
}
case 16:
{
options.ColorType = TiffColorType.BlackIsZero16;
break;
}
case 8:
{
options.ColorType = TiffColorType.BlackIsZero8;
break;
}
case 4:
{
options.ColorType = TiffColorType.BlackIsZero4;
break;
}
case 1:
{
options.ColorType = TiffColorType.BlackIsZero1;
break;
}
default:
{
options.ColorType = TiffColorType.BlackIsZero;
break;
}
}
break;
}
case TiffPhotometricInterpretation.Rgb:
{
TiffBitsPerSample bitsPerSample = options.BitsPerSample;
if (bitsPerSample.Channels != 3)
{
TiffThrowHelper.ThrowNotSupported("The number of samples in the TIFF BitsPerSample entry is not supported.");
}
if (!(bitsPerSample.Channel0 == bitsPerSample.Channel1 && bitsPerSample.Channel1 == bitsPerSample.Channel2))
{
TiffThrowHelper.ThrowNotSupported("Only BitsPerSample with equal bits per channel are supported.");
}
if (options.PlanarConfiguration == TiffPlanarConfiguration.Chunky)
{
ushort bitsPerChannel = options.BitsPerSample.Channel0;
switch (bitsPerChannel)
{
case 32:
if (options.SampleFormat == TiffSampleFormat.Float)
{
options.ColorType = TiffColorType.RgbFloat323232;
return;
}
options.ColorType = TiffColorType.Rgb323232;
break;
case 24:
options.ColorType = TiffColorType.Rgb242424;
break;
case 16:
options.ColorType = TiffColorType.Rgb161616;
break;
case 14:
options.ColorType = TiffColorType.Rgb141414;
break;
case 12:
options.ColorType = TiffColorType.Rgb121212;
break;
case 10:
options.ColorType = TiffColorType.Rgb101010;
break;
case 8:
options.ColorType = TiffColorType.Rgb888;
break;
case 4:
options.ColorType = TiffColorType.Rgb444;
break;
case 2:
options.ColorType = TiffColorType.Rgb222;
break;
default:
TiffThrowHelper.ThrowNotSupported("Bits per sample is not supported.");
break;
}
}
else
{
ushort bitsPerChannel = options.BitsPerSample.Channel0;
switch (bitsPerChannel)
{
case 32:
options.ColorType = TiffColorType.Rgb323232Planar;
break;
case 24:
options.ColorType = TiffColorType.Rgb242424Planar;
break;
case 16:
options.ColorType = TiffColorType.Rgb161616Planar;
break;
default:
options.ColorType = TiffColorType.Rgb888Planar;
break;
}
}
break;
}
case TiffPhotometricInterpretation.PaletteColor:
{
options.ColorMap = exifProfile.GetValue(ExifTag.ColorMap)?.Value;
if (options.ColorMap != null)
{
if (options.BitsPerSample.Channels != 1)
{
TiffThrowHelper.ThrowNotSupported("The number of samples in the TIFF BitsPerSample entry is not supported.");
}
options.ColorType = TiffColorType.PaletteColor;
}
else
{
TiffThrowHelper.ThrowNotSupported("The TIFF ColorMap entry is missing for a palette color image.");
}
break;
}
case TiffPhotometricInterpretation.YCbCr:
{
options.ColorMap = exifProfile.GetValue(ExifTag.ColorMap)?.Value;
if (options.BitsPerSample.Channels != 3)
{
TiffThrowHelper.ThrowNotSupported("The number of samples in the TIFF BitsPerSample entry is not supported.");
}
ushort bitsPerChannel = options.BitsPerSample.Channel0;
if (bitsPerChannel != 8)
{
TiffThrowHelper.ThrowNotSupported("Only 8 bits per channel is supported for YCbCr images.");
}
options.ColorType = options.PlanarConfiguration == TiffPlanarConfiguration.Chunky ? TiffColorType.YCbCr : TiffColorType.YCbCrPlanar;
break;
}
default:
{
TiffThrowHelper.ThrowNotSupported($"The specified TIFF photometric interpretation is not supported: {options.PhotometricInterpretation}");
}
break;
}
}