public PhysicalPixelDimensionsDataChunkRepresentation(PNG parent) : base(parent)
{
}
public BackgroundColorDataChunkRepresentation(PNG parent) : base(parent)
{
}
public TransparentColorDataChunkRepresentation(PNG parent) : base(parent)
{
}
public SuggestedPaletteDataChunkRepresentation(PNG parent) : base(parent)
{
}
public VirtualPageDataChunkRepresentation(PNG parent) : base(parent)
{
}
public HeaderChunkRepresentation(PNG parent) : base(parent)
{
}
public TimestampDataChunkRepresentation(PNG parent) : base(parent)
{
}
public ZippedTextDataChunkRepresentation(PNG parent) : base(parent)
{
}
public InternationalTextDataChunkRepresentation(PNG parent) : base(parent)
{
}
public SignificantBitsDataChunkRepresentation(PNG parent) : base(parent)
{
}
public EmbeddedICCProfileDataChunkRepresentation(PNG parent) : base(parent)
{
}
//The sRGB chunk contains:
//Rendering intent
//1 byte
//The following values are defined for rendering intent:
//0 Perceptual: for images preferring good adaptation to the output device gamut at the expense of colorimetric accuracy, such as photographs.
//1 Relative colorimetric: for images requiring colour appearance matching(relative to the output device white point), such as logos.
//2 Saturation: for images preferring preservation of saturation at the expense of hue and lightness, such as charts and graphs.
//3 Absolute colorimetric: for images requiring preservation of absolute colorimetry, such as previews of images destined for a different output device(proofs).
//It is recommended that a PNG encoder that writes the sRGB chunk also write a gAMA chunk(and optionally a cHRM chunk) for compatibility with decoders that do not use the sRGB chunk.Only the following values shall be used.
//gAMA
//Gamma 45455
//cHRM
//White point x 31270
//White point y 32900
//Red x 64000
//Red y 33000
//Green x 30000
//Green y 60000
//Blue x 15000
//Blue y 6000
//When the sRGB chunk is present, it is recommended that decoders that recognize it and are capable of colour management[ICC] ignore the gAMA and cHRM chunks and use the sRGB chunk instead.Decoders that recognize the sRGB chunk but are not capable of colour management [ICC] are recommended to ignore the gAMA and cHRM chunks, and use the values given above as if they had appeared in gAMA and cHRM chunks.
public StandardRGBDataChunkRepresentation(PNG parent) : base(parent)
{
}
public PrimaryChromaticitiesAndWhitePoint(PNG parent) : base(parent)
{
}
public GammaDataChunkRepresentation(PNG parent) : base(parent)
{
}
public ImageDataChunkRepresentation(PNG parent) : base(parent)
{
}
public HistogramDataChunkRepresentation(PNG parent) : base(parent)
{
}
public DataChunk(BinaryReader reader, PNG parent)
{
byte[] lengthBytes = reader.ReadBytes(4);
Length = (uint)lengthBytes.GetULongBE(0);
byte[] typeBytes = reader.ReadBytes(4);
ChunkTypeBytes = typeBytes;
ChunkType = Encoding.Default.GetString(typeBytes);
Data = reader.ReadBytes((int)Length);
byte[] crcBytes = reader.ReadBytes(4);
CRC = (uint)crcBytes.GetULongBE(0);
byte[] checkBytes = new byte[Data.Length + typeBytes.Length];
Array.Copy(typeBytes, 0, checkBytes, 0, typeBytes.Length);
int dst = typeBytes.Length;
Array.Copy(Data, 0, checkBytes, dst, Data.Length);
CRC crc = new CRC();
ulong crc_result = crc.crc(checkBytes, checkBytes.Length);
if (CRC == crc_result)
{
CRCPassed = true;
}
else
{
CRCPassed = false;
}
switch (ChunkType.ToLower())
{
case "bkgd": DataChunkRepresentation = new BackgroundColorDataChunkRepresentation(parent); break;
case "chrm": DataChunkRepresentation = new PrimaryChromaticitiesAndWhitePoint(parent); break;
case "gama": DataChunkRepresentation = new GammaDataChunkRepresentation(parent); break;
case "hist": DataChunkRepresentation = new HistogramDataChunkRepresentation(parent); break;
case "iccp": DataChunkRepresentation = new EmbeddedICCProfileDataChunkRepresentation(parent); break;
case "idat": DataChunkRepresentation = new ImageDataChunkRepresentation(parent); break;
case "ihdr": DataChunkRepresentation = new HeaderChunkRepresentation(parent); break;
case "itxt": DataChunkRepresentation = new InternationalTextDataChunkRepresentation(parent); break;
case "phys": DataChunkRepresentation = new PhysicalPixelDimensionsDataChunkRepresentation(parent); break;
case "plte": DataChunkRepresentation = new PaletteDataChunkRepresentation(parent); break;
case "sbit": DataChunkRepresentation = new SignificantBitsDataChunkRepresentation(parent); break;
case "splt": DataChunkRepresentation = new SuggestedPaletteDataChunkRepresentation(parent); break;
case "srgb": DataChunkRepresentation = new StandardRGBDataChunkRepresentation(parent); break;
case "text": DataChunkRepresentation = new TextDataChunkRepresentation(parent); break;
case "time": DataChunkRepresentation = new TimestampDataChunkRepresentation(parent); break;
case "vpag": DataChunkRepresentation = new VirtualPageDataChunkRepresentation(parent); break;
case "ztxt": DataChunkRepresentation = new ZippedTextDataChunkRepresentation(parent); break;
default: break;
}
if (DataChunkRepresentation != null)
{
StringBuilder sb = new StringBuilder();
var values = DataChunkRepresentation.ToProperties(Data);
foreach (var val in values)
{
sb.AppendLine(val.Key + " = " + val.Value.ToString());
}
PropertyString = sb.ToString();
}
if (!CRCPassed)
{
throw new InvalidDataException($@"CRC Failure reading data chunk of type {ChunkType} - Expected CRC {CRC}, Actual Checksum Result {crc_result}");
}
}
public DataChunkRepresentationBase(PNG parent)
{
this.Parent = parent;
}