private static Size DecodeJfif(BinaryReader binaryReader)
{
while (binaryReader.ReadByte() == 0xff)
{
byte marker = binaryReader.ReadByte();
short chunkLength = ByteHelper.ReadInt16BE(binaryReader);
if (marker == 0xc0 || marker == 0xc2) // c2: progressive
{
binaryReader.ReadByte();
int height = ByteHelper.ReadInt16BE(binaryReader);
int width = ByteHelper.ReadInt16BE(binaryReader);
return(new Size(width, height));
}
if (chunkLength < 0)
{
ushort uchunkLength = (ushort)chunkLength;
binaryReader.ReadBytes(uchunkLength - 2);
}
else
{
binaryReader.ReadBytes(chunkLength - 2);
}
}
return(Size.Empty);
}
private static Size DecodeTiffBE(BinaryReader binaryReader)
{
int idfStart = ByteHelper.ReadInt32BE(binaryReader);
binaryReader.BaseStream.Seek(idfStart, SeekOrigin.Begin);
int numberOfIDF = ByteHelper.ReadInt16BE(binaryReader);
int width = -1;
int height = -1;
for (int i = 0; i < numberOfIDF; i++)
{
short field = ByteHelper.ReadInt16BE(binaryReader);
switch (field)
{
// https://www.awaresystems.be/imaging/tiff/tifftags/baseline.html
default:
binaryReader.ReadBytes(10);
break;
case 256: // image width
binaryReader.ReadBytes(6);
width = ByteHelper.ReadInt32BE(binaryReader);
break;
case 257: // image length
binaryReader.ReadBytes(6);
height = ByteHelper.ReadInt32BE(binaryReader);
break;
}
if (width != -1 && height != -1)
{
return(new Size(width, height));
}
}
return(Size.Empty);
}