com.levigo.jbig2

Class Bitmap

java.lang.Object

com.levigo.jbig2.Bitmap

public class Bitmap
extends Object

This class represents a bi-level image that is organized like a bitmap.

Author:

Matthäus Krzikalla

Constructor Summary

Constructors

Constructor and Description
Bitmap(int width, int height) Creates an instance of a blank image.

Method Summary

Methods

Modifier and Type	Method and Description
int	getBitOffset(int x) Computes the offset of the given x coordinate in its byte.
Rectangle	getBounds()
byte	getByte(int index) Simply returns a byte from the bitmap byte array.
byte[]	getByteArray() Simply returns the byte array of this bitmap.
int	getByteAsInteger(int index) Converts the byte at specified index into an integer and returns the value.
int	getByteIndex(int x, int y) Returns the index of the byte that contains the pixel, specified by the pixel's x and y coordinates.
int	getHeight() Simply returns the height of this bitmap.
int	getMemorySize()
byte	getPixel(int x, int y) Returns the value of a pixel specified by the given coordinates.
int	getRowStride() Simply returns the row stride of this bitmap.
int	getWidth() Simply returns the width of this bitmap.
void	setByte(int index, byte value) Simply sets the given value at the given array index position.
void	setPixel(int x, int y, byte pixelValue)

Methods inherited from class java.lang.Object

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

Constructor Detail

Bitmap

public Bitmap(int width,
      int height)

Creates an instance of a blank image.
The image data is stored in a byte array. Each pixels is stored as one bit, so that each byte contains 8 pixel. A pixel has by default the value 0 for white and 1 for black.
Row stride means the amount of bytes per line. It is computed automatically and fills the pad bits with 0.

Parameters:

height - - The real height of the bitmap in pixels.

width - - The real width of the bitmap in pixels.

Method Detail

getPixel

public byte getPixel(int x,
            int y)

Returns the value of a pixel specified by the given coordinates.

By default, the value is 0 for a white pixel and 1 for a black pixel. The value is placed in the rightmost bit in the byte.

Parameters:

x - - The x coordinate of the pixel.

y - - The y coordinate of the pixel.

Returns:

The value of a pixel.

setPixel

public void setPixel(int x,
            int y,
            byte pixelValue)

getByteIndex

public int getByteIndex(int x,
               int y)

Returns the index of the byte that contains the pixel, specified by the pixel's x and y coordinates.

Parameters:

x - - The pixel's x coordinate.

y - - The pixel's y coordinate.

Returns:

The index of the byte that contains the specified pixel.

getByteArray

public byte[] getByteArray()

Simply returns the byte array of this bitmap.

Returns:

The byte array of this bitmap.

getByte

public byte getByte(int index)

Simply returns a byte from the bitmap byte array. Throws an IndexOutOfBoundsException if the given index is out of bound.

Parameters:

index - - The array index that specifies the position of the wanted byte.

Returns:

The byte at the index-position.

Throws:

IndexOutOfBoundsException - if the index is out of bound.

setByte

public void setByte(int index,
           byte value)

Simply sets the given value at the given array index position. Throws an IndexOutOfBoundsException if the given index is out of bound.

Parameters:

index - - The array index that specifies the position of a byte.

value - - The byte that should be set.

Throws:

IndexOutOfBoundsException - if the index is out of bound.

getByteAsInteger

public int getByteAsInteger(int index)

Converts the byte at specified index into an integer and returns the value. Throws an IndexOutOfBoundsException if the given index is out of bound.

Parameters:

index - - The array index that specifies the position of the wanted byte.

Returns:

The converted byte at the index-position as an integer.

Throws:

IndexOutOfBoundsException - if the index is out of bound.

getBitOffset

public int getBitOffset(int x)

Computes the offset of the given x coordinate in its byte. The method uses optimized modulo operation for a better performance.

Parameters:

x - - The x coordinate of a pixel.

Returns:

The bit offset of a pixel in its byte.

getHeight

public int getHeight()

Simply returns the height of this bitmap.

Returns:

The height of this bitmap.

getWidth

public int getWidth()

Simply returns the width of this bitmap.

Returns:

The width of this bitmap.

getRowStride

public int getRowStride()

Simply returns the row stride of this bitmap.
(Row stride means the amount of bytes per line.)

Returns:

The row stride of this bitmap.

getBounds

public Rectangle getBounds()

getMemorySize

public int getMemorySize()