/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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extern const int ZX_FINDER_PATTERN_MIN_SKIP;
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extern const int ZX_FINDER_PATTERN_MAX_MODULES;
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@protocol ZXResultPointCallback;
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@class ZXBitMatrix, ZXDecodeHints, ZXQRCodeFinderPatternInfo;
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/**
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* This class attempts to find finder patterns in a QR Code. Finder patterns are the square
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* markers at three corners of a QR Code.
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*
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* This class is thread-safe but not reentrant. Each thread must allocate its own object.
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*/
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@interface ZXQRCodeFinderPatternFinder : NSObject
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@property (nonatomic, strong, readonly) ZXBitMatrix *image;
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@property (nonatomic, strong, readonly) NSMutableArray *possibleCenters;
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/**
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* Creates a finder that will search the image for three finder patterns.
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*
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* @param image image to search
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*/
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- (id)initWithImage:(ZXBitMatrix *)image;
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- (id)initWithImage:(ZXBitMatrix *)image resultPointCallback:(id<ZXResultPointCallback>)resultPointCallback;
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- (ZXQRCodeFinderPatternInfo *)find:(ZXDecodeHints *)hints error:(NSError **)error;
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/**
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* @param stateCount count of black/white/black/white/black pixels just read
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* @return true iff the proportions of the counts is close enough to the 1/1/3/1/1 ratios
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* used by finder patterns to be considered a match
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*/
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+ (BOOL)foundPatternCross:(const int[])stateCount;
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/**
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* This is called when a horizontal scan finds a possible alignment pattern. It will
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* cross check with a vertical scan, and if successful, will, ah, cross-cross-check
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* with another horizontal scan. This is needed primarily to locate the real horizontal
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* center of the pattern in cases of extreme skew.
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* And then we cross-cross-cross check with another diagonal scan.
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*
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* If that succeeds the finder pattern location is added to a list that tracks
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* the number of times each location has been nearly-matched as a finder pattern.
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* Each additional find is more evidence that the location is in fact a finder
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* pattern center
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*
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* @param stateCount reading state module counts from horizontal scan
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* @param i row where finder pattern may be found
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* @param j end of possible finder pattern in row
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* @return true if a finder pattern candidate was found this time
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*/
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- (BOOL)handlePossibleCenter:(const int[])stateCount i:(int)i j:(int)j pureBarcode:(BOOL)pureBarcode;
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@end
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