Package org.apache.pdfbox.filter

Class DCTFilter

java.lang.Object

org.apache.pdfbox.filter.Filter

org.apache.pdfbox.filter.DCTFilter

final class DCTFilter
extends Filter

Decompresses data encoded using a DCT (discrete cosine transform) technique based on the JPEG standard.

Field Summary

Fields

Modifier and Type	Field	Description
private static final String	ADOBE
private static final org.apache.commons.logging.Log	LOG
private static final int	POS_TRANSFORM
private static XPathExpression	xPathExpression

Fields inherited from class org.apache.pdfbox.filter.Filter

SYSPROP_DEFLATELEVEL

Constructor Summary

Constructors

Constructor	Description
DCTFilter()

Method Summary

Modifier and Type	Method	Description
private int	clamp(float value)
DecodeResult	decode(InputStream encoded, OutputStream decoded, COSDictionary parameters, int index)	Decodes data, producing the original non-encoded data.
DecodeResult	decode(InputStream encoded, OutputStream decoded, COSDictionary parameters, int index, DecodeOptions options)	Decodes data, with optional DecodeOptions.
protected void	encode(InputStream input, OutputStream encoded, COSDictionary parameters)
private WritableRaster	fromBGRtoRGB(Raster raster)
private WritableRaster	fromYCbCrtoCMYK(Raster raster)
private WritableRaster	fromYCCKtoCMYK(Raster raster)
private Integer	getAdobeTransform(IIOMetadata metadata)
private int	getAdobeTransformByBruteForce(ImageInputStream iis)
private String	getNumChannels(ImageReader reader)

Methods inherited from class org.apache.pdfbox.filter.Filter

encode, findImageReader, getCompressionLevel, getDecodeParams

Methods inherited from class java.lang.Object

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

Field Details

LOG

private static final org.apache.commons.logging.Log LOG

POS_TRANSFORM

private static final int POS_TRANSFORM

See Also:

• Constant Field Values

ADOBE

private static final String ADOBE

See Also:

• Constant Field Values

xPathExpression

private static XPathExpression xPathExpression

Constructor Details

DCTFilter

DCTFilter()

Method Details

decode

public DecodeResult decode(InputStream encoded,
 OutputStream decoded,
 COSDictionary parameters,
 int index,
 DecodeOptions options)
                    throws IOException

Description copied from class: Filter

Decodes data, with optional DecodeOptions. Not all filters support all options, and so callers should check the options' honored flag to test if they were applied.

Overrides:

decode in class Filter

Parameters:

encoded - the encoded byte stream

decoded - the stream where decoded data will be written

parameters - the parameters used for decoding

index - the index to the filter being decoded

options - additional options for decoding

Returns:

repaired parameters dictionary, or the original parameters dictionary

Throws:

IOException - if the stream cannot be decoded

decode

public DecodeResult decode(InputStream encoded,
 OutputStream decoded,
 COSDictionary parameters,
 int index)
                    throws IOException

Description copied from class: Filter

Decodes data, producing the original non-encoded data.

Specified by:

decode in class Filter

Parameters:

encoded - the encoded byte stream

decoded - the stream where decoded data will be written

parameters - the parameters used for decoding

index - the index to the filter being decoded

Returns:

repaired parameters dictionary, or the original parameters dictionary

Throws:

IOException - if the stream cannot be decoded

getAdobeTransform

private Integer getAdobeTransform(IIOMetadata metadata)

getAdobeTransformByBruteForce

private int getAdobeTransformByBruteForce(ImageInputStream iis)
                                   throws IOException

Throws:

IOException

fromYCCKtoCMYK

private WritableRaster fromYCCKtoCMYK(Raster raster)

fromYCbCrtoCMYK

private WritableRaster fromYCbCrtoCMYK(Raster raster)

fromBGRtoRGB

private WritableRaster fromBGRtoRGB(Raster raster)

getNumChannels

private String getNumChannels(ImageReader reader)

clamp

private int clamp(float value)

encode

protected void encode(InputStream input,
 OutputStream encoded,
 COSDictionary parameters)
               throws IOException

Specified by:

encode in class Filter

Throws:

IOException