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 final float[]	block
private final int[]	blockInt
private final DhtSegment.HuffmanTable[]	huffmanACTables
private final DhtSegment.HuffmanTable[]	huffmanDCTables
private BufferedImage	image
private ImageReadException	imageReadException
private IOException	ioException
private final DqtSegment.QuantizationTable[]	quantizationTables
private final float[][]	scaledQuantizationTables
private SofnSegment	sofnSegment
private SosSegment	sosSegment
private final int[]	zz

Constructor Summary

Constructors

Constructor	Description
JpegDecoder()

Method Summary

Modifier and Type	Method	Description
private Block[]	allocateMCUMemory()
boolean	beginSOS()
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 List<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)
(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 Details

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 BufferedImage image

imageReadException

private ImageReadException imageReadException

ioException

private IOException ioException

zz

private final int[] zz

blockInt

private final int[] blockInt

block

private final float[] block

Constructor Details

JpegDecoder

public JpegDecoder()

Method Details

beginSOS

public boolean beginSOS()

Specified by:

beginSOS in interface JpegUtils.Visitor

visitSOS

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

Specified by:

visitSOS in interface JpegUtils.Visitor

visitSegment

public boolean visitSegment(int marker,
 byte[] markerBytes,
 int segmentLength,
 byte[] segmentLengthBytes,
 byte[] segmentData)
                     throws ImageReadException,
IOException

Specified by:

visitSegment in interface JpegUtils.Visitor

Throws:

ImageReadException

IOException

rescaleMCU

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

allocateMCUMemory

private Block[] allocateMCUMemory()
                           throws ImageReadException

Throws:

ImageReadException

readMCU

private void readMCU(JpegInputStream is,
 int[] preds,
 Block[] mcu)
              throws IOException,
ImageReadException

Throws:

IOException

ImageReadException

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

getIntervalStartPositions

static List<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

fastRound

private static int fastRound(float x)

extend

private int extend(int v,
 int t)

receive

private int receive(int ssss,
 JpegInputStream is)
             throws IOException,
ImageReadException

Throws:

IOException

ImageReadException

decode

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

Throws:

IOException

ImageReadException

decode

public BufferedImage decode(ByteSource byteSource)
                     throws IOException,
ImageReadException

Throws:

IOException

ImageReadException