com.google.zxing.common

Class BitMatrix

java.lang.Object

com.google.zxing.common.BitMatrix

public final class BitMatrix
extends java.lang.Object

Represents a 2D matrix of bits. In function arguments below, and throughout the common module, x is the column position, and y is the row position. The ordering is always x, y. The origin is at the top-left.

Internally the bits are represented in a 1-D array of 32-bit ints. However, each row begins with a new int. This is done intentionally so that we can copy out a row into a BitArray very efficiently.

The ordering of bits is row-major. Within each int, the least significant bits are used first, meaning they represent lower x values. This is compatible with BitArray's implementation.

Constructor Summary

Constructors

Constructor and Description
BitMatrix(int dimension)
BitMatrix(int width, int height)

Method Summary

Modifier and Type	Method and Description
void	clear() Clears all bits (sets to false).
boolean	equals(java.lang.Object o)
void	flip(int x, int y) Flips the given bit.
boolean	get(int x, int y) Gets the requested bit, where true means black.
int[]	getBottomRightOnBit()
int[]	getEnclosingRectangle() This is useful in detecting the enclosing rectangle of a 'pure' barcode.
int	getHeight()
BitArray	getRow(int y, BitArray row) A fast method to retrieve one row of data from the matrix as a BitArray.
int[]	getTopLeftOnBit() This is useful in detecting a corner of a 'pure' barcode.
int	getWidth()
int	hashCode()
void	set(int x, int y) Sets the given bit to true.
void	setRegion(int left, int top, int width, int height) Sets a square region of the bit matrix to true.
void	setRow(int y, BitArray row)
java.lang.String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

BitMatrix

public BitMatrix(int dimension)

BitMatrix

public BitMatrix(int width,
                 int height)

Method Detail

get

public boolean get(int x,
                   int y)

Gets the requested bit, where true means black.

Parameters:

x - The horizontal component (i.e. which column)

y - The vertical component (i.e. which row)

Returns:

value of given bit in matrix

set

public void set(int x,
                int y)

Sets the given bit to true.

Parameters:

x - The horizontal component (i.e. which column)

y - The vertical component (i.e. which row)

flip

public void flip(int x,
                 int y)

Flips the given bit.

Parameters:

x - The horizontal component (i.e. which column)

y - The vertical component (i.e. which row)

clear

public void clear()

Clears all bits (sets to false).

setRegion

public void setRegion(int left,
                      int top,
                      int width,
                      int height)

Sets a square region of the bit matrix to true.

Parameters:

left - The horizontal position to begin at (inclusive)

top - The vertical position to begin at (inclusive)

width - The width of the region

height - The height of the region

getRow

public BitArray getRow(int y,
                       BitArray row)

A fast method to retrieve one row of data from the matrix as a BitArray.

Parameters:

y - The row to retrieve

row - An optional caller-allocated BitArray, will be allocated if null or too small

Returns:

The resulting BitArray - this reference should always be used even when passing your own row

setRow

public void setRow(int y,
                   BitArray row)

Parameters:

y - row to set

row - BitArray to copy from

getEnclosingRectangle

public int[] getEnclosingRectangle()

This is useful in detecting the enclosing rectangle of a 'pure' barcode.

Returns:

{left,top,width,height} enclosing rectangle of all 1 bits, or null if it is all white

getTopLeftOnBit

public int[] getTopLeftOnBit()

This is useful in detecting a corner of a 'pure' barcode.

Returns:

{x,y} coordinate of top-left-most 1 bit, or null if it is all white

getBottomRightOnBit

public int[] getBottomRightOnBit()

getWidth

public int getWidth()

Returns:

The width of the matrix

getHeight

public int getHeight()

Returns:

The height of the matrix

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object