net.sourceforge.jiu.codecs.tiff

Class TIFFDecoder

Known Direct Subclasses:
TIFFDecoderDeflated, TIFFDecoderLogLuv, TIFFDecoderModifiedHuffman, TIFFDecoderPackbits, TIFFDecoderUncompressed

public abstract class TIFFDecoder
extends java.lang.Object

The abstract base class for a TIFF decoder, a class that decompresses one tile or strip of image data and understands one or more compression types. Each child class implements the decoding of a particular TIFF compression type in its decode() method.

This class does all the work of storing decompressed data (given as a byte array) in the image object. Given the many variants (sample order, color depth, color space etc.) this is a larger portion of code.

Author:
Marco Schmidt
Since:
0.7.0

Field Summary

private int
bottomRow
private int
bufferIndex
private TIFFCodec
codec
private int
currentRow
private TIFFImageFileDirectory
ifd
private int
leftColumn
private int
processedTileRows
private int
rightColumn
private byte[]
rowBuffer
private int
tileIndex
private int
topRow
private int
totalTileRows

Constructor Summary

TIFFDecoder()

Method Summary

abstract void
decode()
Decode data from input and write the decompressed pixel data to the image associated with this decoder.
int
getBytesPerRow()
Returns the number of bytes per row for the strip or tile that this decoder deals with.
TIFFCodec
getCodec()
Returns the codec from which this decoder is used.
abstract Integer[]
getCompressionTypes()
Returns an array with Integer values of all compression types supported by this decoder (see the COMPRESSION_xyz constants in TIFFConstants.
TIFFImageFileDirectory
getImageFileDirectory()
Returns the IFD for the image this decoder is supposed to uncompress (partially).
DataInput
getInput()
Returns the input stream from which this decoder is supposed to read data.
int
getTileIndex()
Returns the zero-based index of the tile or strip this decoder is supposed to be decompressing.
int
getX1()
Returns the leftmost column of the image strip / tile to be read by this decoder.
int
getX2()
Returns the rightmost column of the image strip / tile to be read by this decoder.
int
getY1()
Returns the top row of the image strip / tile to be read by this decoder.
int
getY2()
Returns the bottom row of the image strip / tile to be read by this decoder.
void
initialize()
Check if all necessary parameters have been given to this decoder and initialize several internal fields from them.
void
putBytes(byte[] data, int offset, int number)
Adds a number of bytes to the internal row buffer.
void
setCodec(TIFFCodec tiffCodec)
Specify the codec to be used with this decoder.
void
setImageFileDirectory(TIFFImageFileDirectory tiffIfd)
Specify the IFD to be used with this decoder.
void
setTileIndex(int index)
Specify the zero-based tile index for the tile or strip to be decompressed by this decoder.
private void
storeRow(byte[] data, int offset)

Field Details

bottomRow

private int bottomRow

bufferIndex

private int bufferIndex

codec

private TIFFCodec codec

currentRow

private int currentRow

ifd

private TIFFImageFileDirectory ifd

leftColumn

private int leftColumn

processedTileRows

private int processedTileRows

rightColumn

private int rightColumn

rowBuffer

private byte[] rowBuffer

tileIndex

private int tileIndex

topRow

private int topRow

totalTileRows

private int totalTileRows

Constructor Details

TIFFDecoder

public TIFFDecoder()

Method Details

decode

public abstract void decode()
            throws InvalidFileStructureException,
                   IOException
Decode data from input and write the decompressed pixel data to the image associated with this decoder. Child classes must override this method to implement the decoding for a particular compression type.

getBytesPerRow

public int getBytesPerRow()
Returns the number of bytes per row for the strip or tile that this decoder deals with. So with a tiled TIFF and an image width of 500 and a tile width of 100, for an eight bit grayscale image this would return 100 (not 500).
Returns:
number of bytes per row

getCodec

public TIFFCodec getCodec()
Returns the codec from which this decoder is used.
Returns:
TIFFCodec object using this decoder

getCompressionTypes

public abstract Integer[] getCompressionTypes()
Returns an array with Integer values of all compression types supported by this decoder (see the COMPRESSION_xyz constants in TIFFConstants. Normally, this is only one value, but some compression types got assigned more than one constant (e.g. deflated). Also, a decoder could be capable of dealing with more than one type of compression if the compression types are similar enough to justify that. However, typically a decoder can only deal with one type of compression.
Returns:
array with Integer objects of all TIFF compression constants supported by this decoder

getImageFileDirectory

public TIFFImageFileDirectory getImageFileDirectory()
Returns the IFD for the image this decoder is supposed to uncompress (partially).
Returns:
IFD object

getInput

public DataInput getInput()
Returns the input stream from which this decoder is supposed to read data.

getTileIndex

public int getTileIndex()
Returns the zero-based index of the tile or strip this decoder is supposed to be decompressing.
Returns:
tile index

getX1

public int getX1()
Returns the leftmost column of the image strip / tile to be read by this decoder.

getX2

public int getX2()
Returns the rightmost column of the image strip / tile to be read by this decoder.

getY1

public int getY1()
Returns the top row of the image strip / tile to be read by this decoder.

getY2

public int getY2()
Returns the bottom row of the image strip / tile to be read by this decoder.

initialize

public void initialize()
            throws IOException,
                   MissingParameterException
Check if all necessary parameters have been given to this decoder and initialize several internal fields from them. Required parameters are a TIFFCodec object, a TIFFImageFileDirectory object and a tile index.

putBytes

public void putBytes(byte[] data,
                     int offset,
                     int number)
Adds a number of bytes to the internal row buffer. If the row buffer gets full (a complete line is available) that data will be copied to the image. Note that more than one line, exactly one line or only part of a line can be stored in the number bytes in data.
Parameters:
data - byte array with image data that has been decoded
offset - int index into data where the first byte to be stored is situated
number - int number of bytes to be stored

setCodec

public void setCodec(TIFFCodec tiffCodec)
Specify the codec to be used with this decoder. This is a mandatory parameter - without it, initialize() will throw an exception.
Parameters:
tiffCodec - TIFFCodec object to be used by this decoder
See Also:
getCodec()

setImageFileDirectory

public void setImageFileDirectory(TIFFImageFileDirectory tiffIfd)
Specify the IFD to be used with this decoder. This is a mandatory parameter - without it, initialize() will throw an exception.
Parameters:
tiffIfd - object to be used by this decoder

setTileIndex

public void setTileIndex(int index)
Parameters:
index - zero-based tile / strip index

storeRow

private void storeRow(byte[] data,
                      int offset)