Class MultiFinderPatternFinder

java.lang.Object

com.google.zxing.qrcode.detector.FinderPatternFinder

com.google.zxing.multi.qrcode.detector.MultiFinderPatternFinder

public final class MultiFinderPatternFinder
extends FinderPatternFinder

This class attempts to find finder patterns in a QR Code. Finder patterns are the square markers at three corners of a QR Code.

This class is thread-safe but not reentrant. Each thread must allocate its own object.

In contrast to FinderPatternFinder, this class will return an array of all possible QR code locations in the image.

Use the TRY_HARDER hint to ask for a more thorough detection.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	MultiFinderPatternFinder.ModuleSizeComparator	A comparator that orders FinderPatterns by their estimated module size.

Field Summary

Fields

Modifier and Type	Field	Description
private static final float	DIFF_MODSIZE_CUTOFF	More or less arbitrary cutoff point for determining if two finder patterns might belong to the same code if they differ less than DIFF_MODSIZE_CUTOFF pixels/module in their estimated modules sizes.
private static final float	DIFF_MODSIZE_CUTOFF_PERCENT	More or less arbitrary cutoff point for determining if two finder patterns might belong to the same code if they differ less than DIFF_MODSIZE_CUTOFF_PERCENT percent in their estimated modules sizes.
private static final FinderPattern[][]	EMPTY_FP_2D_ARRAY
private static final FinderPattern[]	EMPTY_FP_ARRAY
private static final FinderPatternInfo[]	EMPTY_RESULT_ARRAY
private static final float	MAX_MODULE_COUNT_PER_EDGE
private static final float	MIN_MODULE_COUNT_PER_EDGE

Fields inherited from class FinderPatternFinder

MAX_MODULES, MIN_SKIP

Constructor Summary

Constructors

Constructor	Description
MultiFinderPatternFinder(BitMatrix image, ResultPointCallback resultPointCallback)

Method Summary

Modifier and Type	Method	Description
FinderPatternInfo[]	findMulti(Map<DecodeHintType, ?> hints)
private FinderPattern[][]	selectMultipleBestPatterns()

Methods inherited from class FinderPatternFinder

clearCounts, doClearCounts, doShiftCounts2, foundPatternCross, foundPatternDiagonal, getImage, getPossibleCenters, handlePossibleCenter, handlePossibleCenter, shiftCounts2

Methods inherited from class Object

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

Field Details

EMPTY_RESULT_ARRAY

private static final FinderPatternInfo[] EMPTY_RESULT_ARRAY

EMPTY_FP_ARRAY

private static final FinderPattern[] EMPTY_FP_ARRAY

EMPTY_FP_2D_ARRAY

private static final FinderPattern[][] EMPTY_FP_2D_ARRAY

MAX_MODULE_COUNT_PER_EDGE

private static final float MAX_MODULE_COUNT_PER_EDGE

See Also:

• Constant Field Values

MIN_MODULE_COUNT_PER_EDGE

private static final float MIN_MODULE_COUNT_PER_EDGE

See Also:

• Constant Field Values

DIFF_MODSIZE_CUTOFF_PERCENT

private static final float DIFF_MODSIZE_CUTOFF_PERCENT

More or less arbitrary cutoff point for determining if two finder patterns might belong to the same code if they differ less than DIFF_MODSIZE_CUTOFF_PERCENT percent in their estimated modules sizes.

See Also:

• Constant Field Values

DIFF_MODSIZE_CUTOFF

private static final float DIFF_MODSIZE_CUTOFF

More or less arbitrary cutoff point for determining if two finder patterns might belong to the same code if they differ less than DIFF_MODSIZE_CUTOFF pixels/module in their estimated modules sizes.

See Also:

• Constant Field Values

Constructor Details

MultiFinderPatternFinder

public MultiFinderPatternFinder(BitMatrix image,
 ResultPointCallback resultPointCallback)

Method Details

selectMultipleBestPatterns

private FinderPattern[][] selectMultipleBestPatterns()
                                              throws NotFoundException

Returns:

the 3 best FinderPatterns from our list of candidates. The "best" are those that have been detected at least 2 times, and whose module size differs from the average among those patterns the least

Throws:

NotFoundException - if 3 such finder patterns do not exist

findMulti

public FinderPatternInfo[] findMulti(Map<DecodeHintType, ?> hints)
                              throws NotFoundException

Throws:

NotFoundException