bitmaps
Class Bitmap

java.lang.Object
  bitmaps.Bitmap

Direct Known Subclasses:

MonochromeBitmap

public class Bitmap
extends java.lang.Object

Note that the use of integers prevents images from being used if they have more than Integer.MAX_VALUE pixels either vertically or horizontally. Note: Pixel rows must always be a multiple of four in length and residual spaces are padded with zeroes...these should not be modified by any steganography implementations.

Author:

Jonathan L Dautrich Jr.

Field Summary

(package private) int	bitsPerPixel
(package private) int	byteRowPadding
(package private) int	bytesPerPixel
(package private) int	colorTableCount
(package private) long	dataStartLocation
private static int	FILE_HEADER_LENGTH
private byte[]	fileHeader
(package private) long	fileSize
(package private) int	fillerLength
private byte[]	fillerSpace
private byte[]	infoHeader
(package private) int	infoHeaderLength
private static int	IOS
private static int	MIN_INFO_HEADER_LENGTH
(package private) int	pixelHeight
private Pixel[][]	pixels
(package private) int	pixelWidth
(package private) int	rowByteCount
private byte[][]	rowPadding
private byte[]	trailingData
private boolean	verbose

Constructor Summary

Bitmap(Bitmap bitmap)
Creates a new Bitmap from the specified bitmap, deep cloning it down to the primitive fields.

Bitmap(java.io.File file)

Bitmap(int bitsPerPixel, int pixelHeight, int pixelWidth)
Creates a new bitmap, setting header values based on parameters.

Method Summary

private void	extractHeaderData() Populates the global header fields with the appropriate values from the byte arrays.
private void	extractPixelData(java.io.FileInputStream inStream) Stores the pixel data from the file in the 2-D pixels Pixel object array
static long	getDataValue(byte[] bytes, int start, int end) Bytes are expected to be in little endian format.
int	getPixelCount()
int	getPixelHeight()
Pixel[][]	getPixels() Returns the bitmap pixel array reference.
int	getPixelWidth()
private void	handleException(java.lang.Exception e)
boolean	isVerbose()
private int	longToInt(long val, java.lang.String err) Converts a long to an int, ensuring the value does not exceed max int value.
private void	printArraySizes()
private void	printHeaderData()
static long	setDataValue(long value, byte[] bytes, int start, int end) Bytes will be in little endian format.
private void	setHeaderData() Sets data in the infoHeader and fileHeader based on the bitmaps current field values.
void	setVerbose(boolean verbose)
private void	writePixelBitData(java.io.FileOutputStream outStream)
private void	writePixelData(java.io.FileOutputStream outStream)
void	writeToFile(java.io.File outFile) Writes the current bitmap out to the specified file.
void	writeToFileGrayscale(java.io.File outFile) Writes the current bitmap out to the specified file, first matching all blue and green pixel values to the red pixel values, to produce a gray-scale image.

Methods inherited from class java.lang.Object

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

Field Detail

FILE_HEADER_LENGTH

private static final int FILE_HEADER_LENGTH

See Also:

Constant Field Values

MIN_INFO_HEADER_LENGTH

private static final int MIN_INFO_HEADER_LENGTH

See Also:

Constant Field Values

IOS

private static final int IOS

See Also:

Constant Field Values

fileHeader

private byte[] fileHeader

infoHeader

private byte[] infoHeader

fillerSpace

private byte[] fillerSpace

pixels

private Pixel[][] pixels

rowPadding

private byte[][] rowPadding

trailingData

private byte[] trailingData

verbose

private boolean verbose

fileSize

long fileSize

infoHeaderLength

int infoHeaderLength

dataStartLocation

long dataStartLocation

fillerLength

int fillerLength

pixelWidth

int pixelWidth

pixelHeight

int pixelHeight

bitsPerPixel

int bitsPerPixel

bytesPerPixel

int bytesPerPixel

byteRowPadding

int byteRowPadding

rowByteCount

int rowByteCount

colorTableCount

int colorTableCount

Constructor Detail

Bitmap

public Bitmap(java.io.File file)
       throws java.io.IOException

Throws:

java.io.IOException

Bitmap

public Bitmap(Bitmap bitmap)

Creates a new Bitmap from the specified bitmap, deep cloning it down to the primitive fields.

Parameters:

bitmap -

Bitmap

public Bitmap(int bitsPerPixel,
              int pixelHeight,
              int pixelWidth)

Creates a new bitmap, setting header values based on parameters. Initializes with all-zero pixel values.

Parameters:

bitsPerPixel -

pixelHeight -

pixelWidth -

Method Detail

setHeaderData

private void setHeaderData()

Sets data in the infoHeader and fileHeader based on the bitmaps current field values. Overwrites any existing values. Assumes values are consistent (e.g. pixelWidth, pixelHeight, bitsPerPixel and fileSize, etc.)

getPixels

public Pixel[][] getPixels()

Returns the bitmap pixel array reference.

Returns:

writeToFile

public void writeToFile(java.io.File outFile)

Writes the current bitmap out to the specified file.

Parameters:

outFile -

writeToFileGrayscale

public void writeToFileGrayscale(java.io.File outFile)

Writes the current bitmap out to the specified file, first matching all blue and green pixel values to the red pixel values, to produce a gray-scale image.

Parameters:

outFile -

writePixelData

private void writePixelData(java.io.FileOutputStream outStream)
                     throws java.io.IOException

Throws:

java.io.IOException

writePixelBitData

private void writePixelBitData(java.io.FileOutputStream outStream)
                        throws java.io.IOException

Throws:

java.io.IOException

extractHeaderData

private void extractHeaderData()

Populates the global header fields with the appropriate values from the byte arrays.

printHeaderData

private void printHeaderData()

printArraySizes

private void printArraySizes()

extractPixelData

private void extractPixelData(java.io.FileInputStream inStream)
                       throws java.io.IOException

Stores the pixel data from the file in the 2-D pixels Pixel object array

Throws:

java.io.IOException

getDataValue

public static long getDataValue(byte[] bytes,
                                int start,
                                int end)

Bytes are expected to be in little endian format. Seven bytes at most can be handled. Returned value will be unsigned. Byte range includes byte start, byte end, and all bytes in-between.

Parameters:

bytes -

start -

end -

Returns:

Value of byte range taken from little endian format, or -1 if something is wrong with the byte range.

setDataValue

public static long setDataValue(long value,
                                byte[] bytes,
                                int start,
                                int end)

Bytes will be in little endian format. Input should be a positive integer. Will set the bytes in the specified range to the long value. Thus seven bytes at most can be set. Byte range includes byte start, byte end, and all bytes in-between.

Parameters:

bytes -

start -

end -

Returns:

Actual value to which the bytes have been set, or -1 if something is wrong with the byte range.

longToInt

private int longToInt(long val,
                      java.lang.String err)

Converts a long to an int, ensuring the value does not exceed max int value.

Parameters:

val -

err -

Returns:

handleException

private void handleException(java.lang.Exception e)

getPixelWidth

public int getPixelWidth()

getPixelHeight

public int getPixelHeight()

getPixelCount

public int getPixelCount()

isVerbose

public boolean isVerbose()

Returns:

current output verbosity boolean

setVerbose

public void setVerbose(boolean verbose)

Parameters:

verbose - sets verbose output boolean