Package org.apache.commons.imaging.formats.jpeg.decoder

Class JpegDecoder

java.lang.Object

org.apache.commons.imaging.common.BinaryFileParser

org.apache.commons.imaging.formats.jpeg.decoder.JpegDecoder

All Implemented Interfaces:

JpegUtils.Visitor

public class JpegDecoder
extends BinaryFileParser
implements JpegUtils.Visitor

Field Summary

Fields

Modifier and Type	Field	Description
private static int[]	BAND_MASK_ARGB
private static int[]	BAND_MASK_RGB
private float[]	block
private int[]	blockInt
private DhtSegment.HuffmanTable[]	huffmanACTables
private DhtSegment.HuffmanTable[]	huffmanDCTables
private java.awt.image.BufferedImage	image
private ImagingException	imageReadException
private java.io.IOException	ioException
private DqtSegment.QuantizationTable[]	quantizationTables
private float[][]	scaledQuantizationTables
private SofnSegment	sofnSegment
private SosSegment	sosSegment
private boolean	useTiffRgb
private int[]	zz

Constructor Summary

Constructors

Constructor	Description
JpegDecoder()	Constructs a new instance with the default, big-endian, byte order.

Method Summary

Modifier and Type	Method	Description
private Block[]	allocateMcuMemory()
boolean	beginSos()
java.awt.image.BufferedImage	decode(ByteSource byteSource)
private int	decode(JpegInputStream is, DhtSegment.HuffmanTable huffmanTable)
private int	extend(int v, int t)
private static int	fastRound(float x)
(package private) static java.util.List<java.lang.Integer>	getIntervalStartPositions(int[] scanPayload)	Returns the positions of where each interval in the provided array starts.
private void	readMcu(JpegInputStream is, int[] preds, Block[] mcu)
private int	receive(int ssss, JpegInputStream is)
private void	rescaleMcu(Block[] dataUnits, int hSize, int vSize, Block[] ret)
void	setTiffRgb()	Sets the decoder to treat incoming data as using the RGB color model.
(package private) static JpegInputStream[]	splitByRstMarkers(int[] scanPayload)	Returns an array of JpegInputStream where each field contains the JpegInputStream for one interval.
boolean	visitSegment(int marker, byte[] markerBytes, int segmentLength, byte[] segmentLengthBytes, byte[] segmentData)
void	visitSos(int marker, byte[] markerBytes, byte[] imageData)

Methods inherited from class org.apache.commons.imaging.common.BinaryFileParser

debugNumber, debugNumber, getByteOrder, setByteOrder

Methods inherited from class java.lang.Object

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

Field Detail

BAND_MASK_ARGB

private static final int[] BAND_MASK_ARGB

BAND_MASK_RGB

private static final int[] BAND_MASK_RGB

quantizationTables

private final DqtSegment.QuantizationTable[] quantizationTables

huffmanDCTables

private final DhtSegment.HuffmanTable[] huffmanDCTables

huffmanACTables

private final DhtSegment.HuffmanTable[] huffmanACTables

sofnSegment

private SofnSegment sofnSegment

sosSegment

private SosSegment sosSegment

scaledQuantizationTables

private final float[][] scaledQuantizationTables

image

private java.awt.image.BufferedImage image

imageReadException

private ImagingException imageReadException

ioException

private java.io.IOException ioException

zz

private final int[] zz

blockInt

private final int[] blockInt

block

private final float[] block

useTiffRgb

private boolean useTiffRgb

Constructor Detail

JpegDecoder

public JpegDecoder()

Constructs a new instance with the default, big-endian, byte order.

Method Detail

fastRound

private static int fastRound(float x)

getIntervalStartPositions

static java.util.List<java.lang.Integer> getIntervalStartPositions(int[] scanPayload)

Returns the positions of where each interval in the provided array starts. The number of start positions is also the count of intervals while the number of restart markers found is equal to the number of start positions minus one (because restart markers are between intervals).

Parameters:

scanPayload - array to examine

Returns:

the start positions

splitByRstMarkers

static JpegInputStream[] splitByRstMarkers(int[] scanPayload)

Returns an array of JpegInputStream where each field contains the JpegInputStream for one interval.

Parameters:

scanPayload - array to read intervals from

Returns:

JpegInputStreams for all intervals, at least one stream is always provided

allocateMcuMemory

private Block[] allocateMcuMemory()
                           throws ImagingException

Throws:

ImagingException

beginSos

public boolean beginSos()

Specified by:

beginSos in interface JpegUtils.Visitor

decode

public java.awt.image.BufferedImage decode(ByteSource byteSource)
                                    throws java.io.IOException,
                                           ImagingException

Throws:

java.io.IOException

ImagingException

decode

private int decode(JpegInputStream is,
                   DhtSegment.HuffmanTable huffmanTable)
            throws ImagingException

Throws:

ImagingException

extend

private int extend(int v,
                   int t)

readMcu

private void readMcu(JpegInputStream is,
                     int[] preds,
                     Block[] mcu)
              throws ImagingException

Throws:

ImagingException

receive

private int receive(int ssss,
                    JpegInputStream is)
             throws ImagingException

Throws:

ImagingException

rescaleMcu

private void rescaleMcu(Block[] dataUnits,
                        int hSize,
                        int vSize,
                        Block[] ret)

setTiffRgb

public void setTiffRgb()

Sets the decoder to treat incoming data as using the RGB color model. This extension to the JPEG specification is intended to support TIFF files that use JPEG compression.

visitSegment

public boolean visitSegment(int marker,
                            byte[] markerBytes,
                            int segmentLength,
                            byte[] segmentLengthBytes,
                            byte[] segmentData)
                     throws ImagingException,
                            java.io.IOException

Specified by:

visitSegment in interface JpegUtils.Visitor

Throws:

ImagingException

java.io.IOException

visitSos

public void visitSos(int marker,
                     byte[] markerBytes,
                     byte[] imageData)

Specified by:

visitSos in interface JpegUtils.Visitor