gnu.javax.imageio.jpeg

Class ZigZag


public class ZigZag
extends Object

This class implements the Zig Zag Algorithm on any array with the same amount of rows and columns. It takes a matrix and in turn builds an encoded byte array (or double array) from it. The adverse is also true, this will take a byte or double array and build a matrix based on the zig zag algorithm.

This is used exclusively in the JPEG DCT encoding.

Field Summary

static int[]
ZIGZAG_8X8_MAP
static boolean
ZIGZAG_BACKWARD
static boolean
ZIGZAG_FORWARD

Method Summary

static byte[][]
decode(byte[] data)
Convert a byte array into a matrix with the same amount of columns and rows with length sqrt(double array length)
static byte[][]
decode(byte[] data, int width, int height)
static double[][]
decode(double[] data)
Convert a double array into a matrix with the same amount of columns and rows with length sqrt(double array length)
static double[][]
decode(double[] data, int width, int height)
static float[][]
decode(float[] data, int width, int height)
static int[][]
decode(int[] data)
static int[][]
decode(int[] data, int width, int height)
static double[][]
decode8x8_map(input[] )
static byte[]
encode(byte[][] matrix)
Encodes a matrix of equal width and height to a byte array.
static double[]
encode(double[][] matrix)
Encodes a matrix of equal width and height to a double array
static float[]
encode(float[][] matrix)
Encodes a matrix of equal width and height to a float array
static short[]
encode(short[][] matrix)
Encodes a matrix of equal width and height to a float array

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ZIGZAG_8X8_MAP

public static final int[] ZIGZAG_8X8_MAP

ZIGZAG_BACKWARD

public static final boolean ZIGZAG_BACKWARD
Field Value:
false

ZIGZAG_FORWARD

public static final boolean ZIGZAG_FORWARD
Field Value:
true

Method Details

decode

public static byte[][] decode(byte[] data)
Convert a byte array into a matrix with the same amount of columns and rows with length sqrt(double array length)
Parameters:
data -
Returns:

decode

public static byte[][] decode(byte[] data,
                              int width,
                              int height)

decode

public static double[][] decode(double[] data)
Convert a double array into a matrix with the same amount of columns and rows with length sqrt(double array length)
Parameters:
data -
Returns:

decode

public static double[][] decode(double[] data,
                                int width,
                                int height)

decode

public static float[][] decode(float[] data,
                               int width,
                               int height)

decode

public static int[][] decode(int[] data)

decode

public static int[][] decode(int[] data,
                             int width,
                             int height)

decode8x8_map

public static double[][] decode8x8_map(input[] )

encode

public static byte[] encode(byte[][] matrix)
Encodes a matrix of equal width and height to a byte array.
Parameters:
matrix -
Returns:

encode

public static double[] encode(double[][] matrix)
Encodes a matrix of equal width and height to a double array
Parameters:
matrix -
Returns:

encode

public static float[] encode(float[][] matrix)
Encodes a matrix of equal width and height to a float array
Parameters:
matrix -
Returns:

encode

public static short[] encode(short[][] matrix)
Encodes a matrix of equal width and height to a float array
Parameters:
matrix -
Returns:

ZigZag.java -- Copyright (C) 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.