private static Size DecodeTiffLE(BinaryReader binaryReader)
{
if (binaryReader.ReadByte() != 0)
{
return(Size.Empty);
}
int idfStart = ByteHelper.ReadInt32LE(binaryReader);
binaryReader.BaseStream.Seek(idfStart, SeekOrigin.Begin);
int numberOfIDF = ByteHelper.ReadInt16LE(binaryReader);
int width = -1;
int height = -1;
for (int i = 0; i < numberOfIDF; i++)
{
short field = ByteHelper.ReadInt16LE(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.ReadInt32LE(binaryReader);
break;
case 257: // image length
binaryReader.ReadBytes(6);
height = ByteHelper.ReadInt32LE(binaryReader);
break;
}
if (width != -1 && height != -1)
{
return(new Size(width, height));
}
}
return(Size.Empty);
}
/// <summary>
/// Gets the dimensions of an image.
/// </summary>
/// <param name="path">The path of the image to get the dimensions of.</param>
/// <returns>The dimensions of the specified image.</returns>
/// <exception cref="ArgumentException">The image was of an unrecognised format.</exception>
public static Size GetDimensions(BinaryReader binaryReader)
{
byte[] magicBytes = new byte[MAX_MAGIC_BYTE_LENGTH];
for (int i = 0; i < MAX_MAGIC_BYTE_LENGTH; i += 1)
{
magicBytes[i] = binaryReader.ReadByte();
foreach (KeyValuePair <byte[], Func <BinaryReader, Size> > kvPair in Image_Format_Decoders)
{
if (ByteHelper.StartsWith(magicBytes, kvPair.Key))
{
return(kvPair.Value(binaryReader));
}
}
}
return(Size.Empty);
}
/// <summary>
/// Checks if param 2 starts with param 1.
/// </summary>
/// <returns>True if param 2 starts with param 1.</returns>
public static bool StartsWith(this byte[] thisBytes, byte[] thatBytes)
{
return(ByteHelper.StartsWith(thatBytes, thisBytes));
}
