Package com.sun.pdfview.decode
Class PNGPredictor
java.lang.Object
com.sun.pdfview.decode.Predictor
com.sun.pdfview.decode.PNGPredictor
Undo prediction based on the PNG algorithm.
-
Field Summary
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected 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 algorithmunpredict
(ByteBuffer imageData) Undo data based on the png algorithmMethods inherited from class com.sun.pdfview.decode.Predictor
getAlgorithm, getBitsPerComponent, getColors, getColumns, getPredictor, setBitsPerComponent, setColors, setColumns
-
Constructor Details
-
PNGPredictor
public PNGPredictor()Creates a new instance of PNGPredictor
-
-
Method Details
-
unpredict
Undo data based on the png algorithm- Specified by:
unpredict
in classPredictor
- Throws:
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
-