jpview.io
Class JPEGLRGBReader

java.lang.Object
  jpview.io.JPEGLRGBReader

All Implemented Interfaces:

PTMReader

public class JPEGLRGBReader
extends java.lang.Object
implements PTMReader

The JPEGLRGBReader implementation provides a reader for the JPEGLRGB format, which compresses coefficient planes using a JPEG encoding

Author:

Default

Constructor Summary

JPEGLRGBReader(java.io.InputStream inputStream)
Creates a new instance of a JPEGLRGBReader from the given InputStream

Method Summary

static int[]	combine(int[] green, byte[] _blue) Combines two coefficient planes
static int[]	convert(byte[] a) Converts an array of unsigned bytes to integers
static int	indexOf(int question, int[] a) Returns the index of a given value in an array
static java.awt.image.BufferedImage	invert(java.awt.image.BufferedImage source) Inverts an image - one of the help functions for unpacking the coefficient planes
static int[]	invert(int[] source) Inverts a pixel buffer - used for unpacking the coefficient planes
static void	main(java.lang.String[] args) Main method for testing
PTM	readPTM() Calls the read procedure

Methods inherited from class java.lang.Object

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

Constructor Detail

JPEGLRGBReader

public JPEGLRGBReader(java.io.InputStream inputStream)

Creates a new instance of a JPEGLRGBReader from the given InputStream

Parameters:

inputStream - The input stream used to read the PTM

Method Detail

readPTM

public PTM readPTM()
            throws java.io.IOException

Calls the read procedure

Specified by:

readPTM in interface PTMReader

Returns:

the LRGBPTM

Throws:

java.io.IOException - If the input stream isn't readable

invert

public static java.awt.image.BufferedImage invert(java.awt.image.BufferedImage source)

Inverts an image - one of the help functions for unpacking the coefficient planes

Parameters:

source - the source image

Returns:

an inverted image

invert

public static int[] invert(int[] source)

Inverts a pixel buffer - used for unpacking the coefficient planes

Parameters:

source - the source pixel buffer

Returns:

the inverted buffer

main

public static void main(java.lang.String[] args)

Main method for testing

Parameters:

args - args[0] is the name of a JPEGLRGB file

convert

public static int[] convert(byte[] a)

Converts an array of unsigned bytes to integers

Parameters:

a - the array of unsigned bytes

Returns:

a copy of the source array as integers

combine

public static int[] combine(int[] green,
                            byte[] _blue)

Combines two coefficient planes

Parameters:

green - the first coefficient plane

_blue - the second coefficient plane

Returns:

the combined result

indexOf

public static int indexOf(int question,
                          int[] a)

Returns the index of a given value in an array

Parameters:

question - the value to look for

a - the array to search

Returns:

the (first) index of the value in the array, if found