com.google.zxing

Class BinaryBitmap

java.lang.Object

com.google.zxing.BinaryBitmap

public final class BinaryBitmap
extends Object

This class is the core bitmap class used by ZXing to represent 1 bit data. Reader objects accept a BinaryBitmap and attempt to decode it.

Author:

dswitkin@google.com (Daniel Switkin)

Constructor Summary

Constructors

Constructor and Description
BinaryBitmap(Binarizer binarizer)

Method Summary

Modifier and Type	Method and Description
BinaryBitmap	crop(int left, int top, int width, int height) Returns a new object with cropped image data.
BitMatrix	getBlackMatrix() Converts a 2D array of luminance data to 1 bit.
BitArray	getBlackRow(int y, BitArray row) Converts one row of luminance data to 1 bit data.
int	getHeight()
int	getWidth()
boolean	isCropSupported()
boolean	isRotateSupported()
BinaryBitmap	rotateCounterClockwise() Returns a new object with rotated image data by 90 degrees counterclockwise.
BinaryBitmap	rotateCounterClockwise45() Returns a new object with rotated image data by 45 degrees counterclockwise.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

BinaryBitmap

public BinaryBitmap(Binarizer binarizer)

Method Detail

getWidth

public int getWidth()

Returns:

The width of the bitmap.

getHeight

public int getHeight()

Returns:

The height of the bitmap.

getBlackRow

public BitArray getBlackRow(int y,
                            BitArray row)
                     throws NotFoundException

Converts one row of luminance data to 1 bit data. May actually do the conversion, or return cached data. Callers should assume this method is expensive and call it as seldom as possible. This method is intended for decoding 1D barcodes and may choose to apply sharpening.

Parameters:

y - The row to fetch, which must be in [0, bitmap height)

row - An optional preallocated array. If null or too small, it will be ignored. If used, the Binarizer will call BitArray.clear(). Always use the returned object.

Returns:

The array of bits for this row (true means black).

Throws:

NotFoundException - if row can't be binarized

getBlackMatrix

public BitMatrix getBlackMatrix()
                         throws NotFoundException

Converts a 2D array of luminance data to 1 bit. As above, assume this method is expensive and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or may not apply sharpening. Therefore, a row from this matrix may not be identical to one fetched using getBlackRow(), so don't mix and match between them.

Returns:

The 2D array of bits for the image (true means black).

Throws:

NotFoundException - if image can't be binarized to make a matrix

isCropSupported

public boolean isCropSupported()

Returns:

Whether this bitmap can be cropped.

crop

public BinaryBitmap crop(int left,
                         int top,
                         int width,
                         int height)

Returns a new object with cropped image data. Implementations may keep a reference to the original data rather than a copy. Only callable if isCropSupported() is true.

Parameters:

left - The left coordinate, which must be in [0,getWidth())

top - The top coordinate, which must be in [0,getHeight())

width - The width of the rectangle to crop.

height - The height of the rectangle to crop.

Returns:

A cropped version of this object.

isRotateSupported

public boolean isRotateSupported()

Returns:

Whether this bitmap supports counter-clockwise rotation.

rotateCounterClockwise

public BinaryBitmap rotateCounterClockwise()

Returns a new object with rotated image data by 90 degrees counterclockwise. Only callable if isRotateSupported() is true.

Returns:

A rotated version of this object.

rotateCounterClockwise45

public BinaryBitmap rotateCounterClockwise45()

Returns a new object with rotated image data by 45 degrees counterclockwise. Only callable if isRotateSupported() is true.

Returns:

A rotated version of this object.

toString

public String toString()

Overrides:

toString in class Object