com.sun.pdfview.decode
Class PNGPredictor

java.lang.Object
  extended by com.sun.pdfview.decode.Predictor
      extended by com.sun.pdfview.decode.PNGPredictor

public class PNGPredictor
extends Predictor

Undo prediction based on the PNG algorithm.


Field Summary
 
Fields inherited from class com.sun.pdfview.decode.Predictor
PNG, TIFF
 
Constructor Summary
PNGPredictor()
          Creates a new instance of PNGPredictor
 
Method Summary
protected  void doAverageLine(byte[] curLine, byte[] prevLine)
          Return the value of the average algorithm on the line (compare bytes to the average of the previous byte of the same color and the same byte on the previous line)
protected  void doPaethLine(byte[] curLine, byte[] prevLine)
          Return the value of the average algorithm on the line (compare bytes to the average of the previous byte of the same color and the same byte on the previous line)
protected  void doSubLine(byte[] curLine)
          Return the value of the Sub algorithm on the line (compare bytes to the previous byte of the same color on this line).
protected  void doUpLine(byte[] curLine, byte[] prevLine)
          Return the value of the up algorithm on the line (compare bytes to the same byte in the previous line)
protected  int paeth(int left, int up, int upLeft)
          The paeth algorithm
 java.nio.ByteBuffer unpredict(java.nio.ByteBuffer imageData)
          Undo data based on the png algorithm
 
Methods inherited from class com.sun.pdfview.decode.Predictor
getAlgorithm, getBitsPerComponent, getColors, getColumns, getPredictor, setBitsPerComponent, setColors, setColumns
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

PNGPredictor

public PNGPredictor()
Creates a new instance of PNGPredictor

Method Detail

unpredict

public java.nio.ByteBuffer unpredict(java.nio.ByteBuffer imageData)
                              throws java.io.IOException
Undo data based on the png algorithm

Specified by:
unpredict in class Predictor
Throws:
java.io.IOException

doSubLine

protected void doSubLine(byte[] curLine)
Return the value of the Sub algorithm on the line (compare bytes to the previous byte of the same color on this line).


doUpLine

protected void doUpLine(byte[] curLine,
                        byte[] prevLine)
Return the value of the up algorithm on the line (compare bytes to the same byte in the previous line)


doAverageLine

protected void doAverageLine(byte[] curLine,
                             byte[] prevLine)
Return the value of the average algorithm on the line (compare bytes to the average of the previous byte of the same color and the same byte on the previous line)


doPaethLine

protected void doPaethLine(byte[] curLine,
                           byte[] prevLine)
Return the value of the average algorithm on the line (compare bytes to the average of the previous byte of the same color and the same byte on the previous line)


paeth

protected int paeth(int left,
                    int up,
                    int upLeft)
The paeth algorithm