org.apache.pdfbox.pdmodel.graphics.predictor

Class Average

java.lang.Object

org.apache.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm

org.apache.pdfbox.pdmodel.graphics.predictor.Average

public class Average
extends PredictorAlgorithm

We can use raw on the right hand side of the decoding formula because it is already decoded. average(i,j) = raw(i,j) + (raw(i-1,j)+raw(i,j-1)/2 decoding raw(i,j) = avarage(i,j) - (raw(i-1,j)+raw(i,j-1)/2

Version:

$Revision: 1.3 $

Author:

xylifyx@yahoo.co.uk

Constructor Summary

Constructors

Constructor and Description
Average()

Method Summary

Methods

Modifier and Type	Method and Description
void	decodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset, int destDy, int destOffset) decode line of pixel data in src from src_offset and width*bpp bytes forward, put the decoded bytes into dest.
void	encodeLine(byte[] src, byte[] dest, int srcDy, int srcOffset, int destDy, int destOffset) Not an optimal version, but close to the def.

Methods inherited from class org.apache.pdfbox.pdmodel.graphics.predictor.PredictorAlgorithm

aboveLeftPixel, abovePixel, checkBufsiz, decode, encode, getBpp, getFilter, getHeight, getWidth, leftPixel, main, setBpp, setHeight, setWidth

Methods inherited from class java.lang.Object

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

Constructor Detail

Average

public Average()

Method Detail

encodeLine

public void encodeLine(byte[] src,
              byte[] dest,
              int srcDy,
              int srcOffset,
              int destDy,
              int destOffset)

Not an optimal version, but close to the def. encode line of pixel data in src from srcOffset and width*bpp bytes forward, put the decoded bytes into dest.

Specified by:

encodeLine in class PredictorAlgorithm

Parameters:

src - raw image data

dest - encoded data

srcDy - byte offset between lines

srcOffset - beginning of line data

destDy - byte offset between lines

destOffset - beginning of line data

decodeLine

public void decodeLine(byte[] src,
              byte[] dest,
              int srcDy,
              int srcOffset,
              int destDy,
              int destOffset)

decode line of pixel data in src from src_offset and width*bpp bytes forward, put the decoded bytes into dest.

Specified by:

decodeLine in class PredictorAlgorithm

Parameters:

src - encoded image data

dest - raw data

srcDy - byte offset between lines

srcOffset - beginning of line data

destDy - byte offset between lines

destOffset - beginning of line data