Package org.apache.commons.imaging.common.itu_t4

Class T4AndT6Compression

java.lang.Object

org.apache.commons.imaging.common.itu_t4.T4AndT6Compression

public final class T4AndT6Compression
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BLACK
private static final HuffmanTree<Integer>	BLACK_RUN_LENGTHS
private static final HuffmanTree<T4_T6_Tables.Entry>	CONTROL_CODES
static final int	WHITE
private static final HuffmanTree<Integer>	WHITE_RUN_LENGTHS

Constructor Summary

Constructors

Modifier	Constructor	Description
private	T4AndT6Compression()

Method Summary

Modifier and Type	Method	Description
private static int	changingElementAt(int[] line, int position)
private static void	compress1DLine(BitInputStreamFlexible inputStream, BitArrayOutputStream outputStream, int[] referenceLine, int width)
static byte[]	compressModifiedHuffman(byte[] uncompressed, int width, int height)	Compressed with the "Modified Huffman" encoding of section 10 in the TIFF6 specification.
private static int	compressT(int a0, int a1, int b1, BitArrayOutputStream outputStream, int codingA0Color, int[] codingLine)
static byte[]	compressT4_1D(byte[] uncompressed, int width, int height, boolean hasFill)
static byte[]	compressT4_2D(byte[] uncompressed, int width, int height, boolean hasFill, int parameterK)
static byte[]	compressT6(byte[] uncompressed, int width, int height)
static byte[]	decompressModifiedHuffman(byte[] compressed, int width, int height)	Decompresses the "Modified Huffman" encoding of section 10 in the TIFF6 specification.
static byte[]	decompressT4_1D(byte[] compressed, int width, int height, boolean hasFill)	Decompresses T.4 1D encoded data.
static byte[]	decompressT4_2D(byte[] compressed, int width, int height, boolean hasFill)	Decompressed T.4 2D encoded data.
static byte[]	decompressT6(byte[] compressed, int width, int height)	Decompress T.6 encoded data.
private static void	fillRange(BitArrayOutputStream outputStream, int[] referenceRow, int a0, int end, int color)
private static boolean	isEOL(T4_T6_Tables.Entry entry, boolean hasFill)
private static T4_T6_Tables.Entry	lowerBound(T4_T6_Tables.Entry[] entries, int value)
private static int	nextChangingElement(int[] line, int currentColour, int start)
private static int	readTotalRunLength(BitInputStreamFlexible bitStream, int color)
private static void	writeRunLength(BitArrayOutputStream bitStream, int runLength, int color)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

WHITE_RUN_LENGTHS

private static final HuffmanTree<Integer> WHITE_RUN_LENGTHS

BLACK_RUN_LENGTHS

private static final HuffmanTree<Integer> BLACK_RUN_LENGTHS

CONTROL_CODES

private static final HuffmanTree<T4_T6_Tables.Entry> CONTROL_CODES

WHITE

public static final int WHITE

See Also:

• Constant Field Values

BLACK

public static final int BLACK

See Also:

• Constant Field Values

Constructor Details

T4AndT6Compression

private T4AndT6Compression()

Method Details

compress1DLine

private static void compress1DLine(BitInputStreamFlexible inputStream,
 BitArrayOutputStream outputStream,
 int[] referenceLine,
 int width)
                            throws ImageWriteException

Throws:

ImageWriteException

compressModifiedHuffman

public static byte[] compressModifiedHuffman(byte[] uncompressed,
 int width,
 int height)
                                      throws ImageWriteException

Compressed with the "Modified Huffman" encoding of section 10 in the TIFF6 specification. No EOLs, no RTC, rows are padded to end on a byte boundary.

Parameters:

uncompressed - uncompressed byte data

width - image width

height - image height

Returns:

the compressed data

Throws:

ImageWriteException - if it fails to write the compressed data

decompressModifiedHuffman

public static byte[] decompressModifiedHuffman(byte[] compressed,
 int width,
 int height)
                                        throws ImageReadException

Decompresses the "Modified Huffman" encoding of section 10 in the TIFF6 specification. No EOLs, no RTC, rows are padded to end on a byte boundary.

Parameters:

compressed - compressed byte data

width - image width

height - image height

Returns:

the compressed data

Throws:

ImageReadException - if it fails to read the compressed data

compressT4_1D

public static byte[] compressT4_1D(byte[] uncompressed,
 int width,
 int height,
 boolean hasFill)
                            throws ImageWriteException

Throws:

ImageWriteException

decompressT4_1D

public static byte[] decompressT4_1D(byte[] compressed,
 int width,
 int height,
 boolean hasFill)
                              throws ImageReadException

Decompresses T.4 1D encoded data. EOL at the beginning and after each row, can be preceded by fill bits to fit on a byte boundary, no RTC.

Parameters:

compressed - compressed byte data

width - image width

height - image height

hasFill - used to check the end of line

Returns:

the decompressed data

Throws:

ImageReadException - if it fails to read the compressed data

compressT

private static int compressT(int a0,
 int a1,
 int b1,
 BitArrayOutputStream outputStream,
 int codingA0Color,
 int[] codingLine)

compressT4_2D

public static byte[] compressT4_2D(byte[] uncompressed,
 int width,
 int height,
 boolean hasFill,
 int parameterK)
                            throws ImageWriteException

Throws:

ImageWriteException

decompressT4_2D

public static byte[] decompressT4_2D(byte[] compressed,
 int width,
 int height,
 boolean hasFill)
                              throws ImageReadException

Decompressed T.4 2D encoded data. EOL at the beginning and after each row, can be preceded by fill bits to fit on a byte boundary, and is succeeded by a tag bit determining whether the next line is encoded using 1D or 2D. No RTC.

Parameters:

compressed - compressed byte data

width - image width

height - image height

hasFill - used to check the end of line

Returns:

the decompressed data

Throws:

ImageReadException - if it fails to read the compressed data

compressT6

public static byte[] compressT6(byte[] uncompressed,
 int width,
 int height)
                         throws ImageWriteException

Throws:

ImageWriteException

decompressT6

public static byte[] decompressT6(byte[] compressed,
 int width,
 int height)
                           throws ImageReadException

Decompress T.6 encoded data. No EOLs, except for 2 consecutive ones at the end (the EOFB, end of fax block). No RTC. No fill bits anywhere. All data is 2D encoded.

Parameters:

compressed - compressed byte data

width - image width

height - image height

Returns:

the decompressed data

Throws:

ImageReadException - if it fails to read the compressed data

isEOL

private static boolean isEOL(T4_T6_Tables.Entry entry,
 boolean hasFill)

writeRunLength

private static void writeRunLength(BitArrayOutputStream bitStream,
 int runLength,
 int color)

lowerBound

private static T4_T6_Tables.Entry lowerBound(T4_T6_Tables.Entry[] entries,
 int value)

readTotalRunLength

private static int readTotalRunLength(BitInputStreamFlexible bitStream,
 int color)
                               throws ImageReadException

Throws:

ImageReadException

changingElementAt

private static int changingElementAt(int[] line,
 int position)

nextChangingElement

private static int nextChangingElement(int[] line,
 int currentColour,
 int start)

fillRange

private static void fillRange(BitArrayOutputStream outputStream,
 int[] referenceRow,
 int a0,
 int end,
 int color)