Class FinderPatternFinder
- Direct Known Subclasses:
MultiFinderPatternFinder
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.
- Author:
- Sean Owen
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected static final int
protected static final int
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Constructor Summary
ConstructorsConstructorDescriptionFinderPatternFinder
(BitMatrix image) Creates a finder that will search the image for three finder patterns.FinderPatternFinder
(BitMatrix image, ResultPointCallback resultPointCallback) -
Method Summary
Modifier and TypeMethodDescriptionprotected final void
clearCounts
(int[] counts) Deprecated.protected static void
doClearCounts
(int[] counts) protected static void
doShiftCounts2
(int[] stateCount) protected static boolean
foundPatternCross
(int[] stateCount) protected static boolean
foundPatternDiagonal
(int[] stateCount) protected final BitMatrix
getImage()
protected final List<FinderPattern>
protected final boolean
handlePossibleCenter
(int[] stateCount, int i, int j) This is called when a horizontal scan finds a possible alignment pattern.protected final boolean
handlePossibleCenter
(int[] stateCount, int i, int j, boolean pureBarcode) Deprecated.only exists for backwards compatibilityprotected final void
shiftCounts2
(int[] stateCount) Deprecated.
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Field Details
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MIN_SKIP
protected static final int MIN_SKIP- See Also:
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MAX_MODULES
protected static final int MAX_MODULES- See Also:
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Constructor Details
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FinderPatternFinder
Creates a finder that will search the image for three finder patterns.
- Parameters:
image
- image to search
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FinderPatternFinder
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Method Details
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getImage
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getPossibleCenters
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foundPatternCross
protected static boolean foundPatternCross(int[] stateCount) - Parameters:
stateCount
- count of black/white/black/white/black pixels just read- Returns:
- true iff the proportions of the counts is close enough to the 1/1/3/1/1 ratios used by finder patterns to be considered a match
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foundPatternDiagonal
protected static boolean foundPatternDiagonal(int[] stateCount) - Parameters:
stateCount
- count of black/white/black/white/black pixels just read- Returns:
- true iff the proportions of the counts is close enough to the 1/1/3/1/1 ratios used by finder patterns to be considered a match
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clearCounts
Deprecated. -
shiftCounts2
Deprecated. -
doClearCounts
protected static void doClearCounts(int[] counts) -
doShiftCounts2
protected static void doShiftCounts2(int[] stateCount) -
handlePossibleCenter
@Deprecated protected final boolean handlePossibleCenter(int[] stateCount, int i, int j, boolean pureBarcode) Deprecated.only exists for backwards compatibility- Parameters:
stateCount
- reading state module counts from horizontal scani
- row where finder pattern may be foundj
- end of possible finder pattern in rowpureBarcode
- ignored- Returns:
- true if a finder pattern candidate was found this time
- See Also:
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handlePossibleCenter
protected final boolean handlePossibleCenter(int[] stateCount, int i, int j) This is called when a horizontal scan finds a possible alignment pattern. It will cross check with a vertical scan, and if successful, will, ah, cross-cross-check with another horizontal scan. This is needed primarily to locate the real horizontal center of the pattern in cases of extreme skew. And then we cross-cross-cross check with another diagonal scan.
If that succeeds the finder pattern location is added to a list that tracks the number of times each location has been nearly-matched as a finder pattern. Each additional find is more evidence that the location is in fact a finder pattern center
- Parameters:
stateCount
- reading state module counts from horizontal scani
- row where finder pattern may be foundj
- end of possible finder pattern in row- Returns:
- true if a finder pattern candidate was found this time
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