Package com.google.zxing.multi

Class ByQuadrantReader

java.lang.Object

com.google.zxing.multi.ByQuadrantReader

All Implemented Interfaces:

Reader

public final class ByQuadrantReader
extends java.lang.Object
implements Reader

This class attempts to decode a barcode from an image, not by scanning the whole image, but by scanning subsets of the image. This is important when there may be multiple barcodes in an image, and detecting a barcode may find parts of multiple barcode and fail to decode (e.g. QR Codes). Instead this scans the four quadrants of the image -- and also the center 'quadrant' to cover the case where a barcode is found in the center.

See Also:

GenericMultipleBarcodeReader

Field Summary

Fields

Modifier and Type	Field	Description
private Reader	delegate

Constructor Summary

Constructors

Constructor	Description
ByQuadrantReader(Reader delegate)

Method Summary

Modifier and Type	Method	Description
Result	decode(BinaryBitmap image)	Locates and decodes a barcode in some format within an image.
Result	decode(BinaryBitmap image, java.util.Map<DecodeHintType,?> hints)	Locates and decodes a barcode in some format within an image.
private static void	makeAbsolute(ResultPoint[] points, int leftOffset, int topOffset)
void	reset()	Resets any internal state the implementation has after a decode, to prepare it for reuse.

Methods inherited from class java.lang.Object

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

Field Detail

delegate

private final Reader delegate

Constructor Detail

ByQuadrantReader

public ByQuadrantReader(Reader delegate)

Method Detail

decode

public Result decode(BinaryBitmap image)
              throws NotFoundException,
                     ChecksumException,
                     FormatException

Description copied from interface: Reader

Locates and decodes a barcode in some format within an image.

Specified by:

decode in interface Reader

Parameters:

image - image of barcode to decode

Returns:

String which the barcode encodes

Throws:

NotFoundException - if no potential barcode is found

ChecksumException - if a potential barcode is found but does not pass its checksum

FormatException - if a potential barcode is found but format is invalid

decode

public Result decode(BinaryBitmap image,
                     java.util.Map<DecodeHintType,?> hints)
              throws NotFoundException,
                     ChecksumException,
                     FormatException

Description copied from interface: Reader

Locates and decodes a barcode in some format within an image. This method also accepts hints, each possibly associated to some data, which may help the implementation decode.

Specified by:

decode in interface Reader

Parameters:

image - image of barcode to decode

hints - passed as a Map from DecodeHintType to arbitrary data. The meaning of the data depends upon the hint type. The implementation may or may not do anything with these hints.

Returns:

String which the barcode encodes

Throws:

NotFoundException - if no potential barcode is found

ChecksumException - if a potential barcode is found but does not pass its checksum

FormatException - if a potential barcode is found but format is invalid

reset

public void reset()

Description copied from interface: Reader

Resets any internal state the implementation has after a decode, to prepare it for reuse.

Specified by:

reset in interface Reader

makeAbsolute

private static void makeAbsolute(ResultPoint[] points,
                                 int leftOffset,
                                 int topOffset)