mirror of https://github.com/NekoX-Dev/NekoX.git
286 lines
11 KiB
Java
Executable File
286 lines
11 KiB
Java
Executable File
/*
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* Copyright 2009 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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package com.google.zxing.multi.qrcode.detector;
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import com.google.zxing.DecodeHintType;
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import com.google.zxing.NotFoundException;
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import com.google.zxing.ResultPoint;
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import com.google.zxing.ResultPointCallback;
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import com.google.zxing.common.BitMatrix;
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import com.google.zxing.qrcode.detector.FinderPattern;
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import com.google.zxing.qrcode.detector.FinderPatternFinder;
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import com.google.zxing.qrcode.detector.FinderPatternInfo;
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import java.io.Serializable;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.Comparator;
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import java.util.List;
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import java.util.Map;
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/**
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* <p>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.</p>
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*
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* <p>This class is thread-safe but not reentrant. Each thread must allocate its own object.
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*
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* <p>In contrast to {@link FinderPatternFinder}, this class will return an array of all possible
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* QR code locations in the image.</p>
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*
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* <p>Use the TRY_HARDER hint to ask for a more thorough detection.</p>
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*
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* @author Sean Owen
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* @author Hannes Erven
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*/
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final class MultiFinderPatternFinder extends FinderPatternFinder {
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private static final FinderPatternInfo[] EMPTY_RESULT_ARRAY = new FinderPatternInfo[0];
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private static final FinderPattern[] EMPTY_FP_ARRAY = new FinderPattern[0];
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private static final FinderPattern[][] EMPTY_FP_2D_ARRAY = new FinderPattern[0][];
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// TODO MIN_MODULE_COUNT and MAX_MODULE_COUNT would be great hints to ask the user for
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// since it limits the number of regions to decode
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// max. legal count of modules per QR code edge (177)
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private static final float MAX_MODULE_COUNT_PER_EDGE = 180;
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// min. legal count per modules per QR code edge (11)
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private static final float MIN_MODULE_COUNT_PER_EDGE = 9;
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/**
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* More or less arbitrary cutoff point for determining if two finder patterns might belong
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* to the same code if they differ less than DIFF_MODSIZE_CUTOFF_PERCENT percent in their
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* estimated modules sizes.
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*/
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private static final float DIFF_MODSIZE_CUTOFF_PERCENT = 0.05f;
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/**
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* More or less arbitrary cutoff point for determining if two finder patterns might belong
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* to the same code if they differ less than DIFF_MODSIZE_CUTOFF pixels/module in their
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* estimated modules sizes.
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*/
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private static final float DIFF_MODSIZE_CUTOFF = 0.5f;
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/**
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* A comparator that orders FinderPatterns by their estimated module size.
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*/
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private static final class ModuleSizeComparator implements Comparator<FinderPattern>, Serializable {
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@Override
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public int compare(FinderPattern center1, FinderPattern center2) {
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float value = center2.getEstimatedModuleSize() - center1.getEstimatedModuleSize();
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return value < 0.0 ? -1 : value > 0.0 ? 1 : 0;
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}
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}
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MultiFinderPatternFinder(BitMatrix image, ResultPointCallback resultPointCallback) {
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super(image, resultPointCallback);
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}
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/**
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* @return the 3 best {@link FinderPattern}s from our list of candidates. The "best" are
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* those that have been detected at least 2 times, and whose module
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* size differs from the average among those patterns the least
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* @throws NotFoundException if 3 such finder patterns do not exist
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*/
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private FinderPattern[][] selectMultipleBestPatterns() throws NotFoundException {
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List<FinderPattern> possibleCenters = getPossibleCenters();
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int size = possibleCenters.size();
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if (size < 3) {
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// Couldn't find enough finder patterns
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throw NotFoundException.getNotFoundInstance();
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}
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/*
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* Begin HE modifications to safely detect multiple codes of equal size
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*/
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if (size == 3) {
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return new FinderPattern[][] { possibleCenters.toArray(EMPTY_FP_ARRAY) };
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}
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// Sort by estimated module size to speed up the upcoming checks
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Collections.sort(possibleCenters, new ModuleSizeComparator());
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/*
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* Now lets start: build a list of tuples of three finder locations that
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* - feature similar module sizes
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* - are placed in a distance so the estimated module count is within the QR specification
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* - have similar distance between upper left/right and left top/bottom finder patterns
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* - form a triangle with 90° angle (checked by comparing top right/bottom left distance
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* with pythagoras)
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*
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* Note: we allow each point to be used for more than one code region: this might seem
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* counterintuitive at first, but the performance penalty is not that big. At this point,
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* we cannot make a good quality decision whether the three finders actually represent
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* a QR code, or are just by chance laid out so it looks like there might be a QR code there.
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* So, if the layout seems right, lets have the decoder try to decode.
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*/
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List<FinderPattern[]> results = new ArrayList<>(); // holder for the results
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for (int i1 = 0; i1 < (size - 2); i1++) {
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FinderPattern p1 = possibleCenters.get(i1);
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if (p1 == null) {
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continue;
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}
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for (int i2 = i1 + 1; i2 < (size - 1); i2++) {
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FinderPattern p2 = possibleCenters.get(i2);
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if (p2 == null) {
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continue;
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}
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// Compare the expected module sizes; if they are really off, skip
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float vModSize12 = (p1.getEstimatedModuleSize() - p2.getEstimatedModuleSize()) /
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Math.min(p1.getEstimatedModuleSize(), p2.getEstimatedModuleSize());
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float vModSize12A = Math.abs(p1.getEstimatedModuleSize() - p2.getEstimatedModuleSize());
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if (vModSize12A > DIFF_MODSIZE_CUTOFF && vModSize12 >= DIFF_MODSIZE_CUTOFF_PERCENT) {
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// break, since elements are ordered by the module size deviation there cannot be
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// any more interesting elements for the given p1.
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break;
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}
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for (int i3 = i2 + 1; i3 < size; i3++) {
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FinderPattern p3 = possibleCenters.get(i3);
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if (p3 == null) {
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continue;
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}
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// Compare the expected module sizes; if they are really off, skip
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float vModSize23 = (p2.getEstimatedModuleSize() - p3.getEstimatedModuleSize()) /
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Math.min(p2.getEstimatedModuleSize(), p3.getEstimatedModuleSize());
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float vModSize23A = Math.abs(p2.getEstimatedModuleSize() - p3.getEstimatedModuleSize());
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if (vModSize23A > DIFF_MODSIZE_CUTOFF && vModSize23 >= DIFF_MODSIZE_CUTOFF_PERCENT) {
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// break, since elements are ordered by the module size deviation there cannot be
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// any more interesting elements for the given p1.
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break;
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}
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FinderPattern[] test = {p1, p2, p3};
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ResultPoint.orderBestPatterns(test);
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// Calculate the distances: a = topleft-bottomleft, b=topleft-topright, c = diagonal
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FinderPatternInfo info = new FinderPatternInfo(test);
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float dA = ResultPoint.distance(info.getTopLeft(), info.getBottomLeft());
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float dC = ResultPoint.distance(info.getTopRight(), info.getBottomLeft());
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float dB = ResultPoint.distance(info.getTopLeft(), info.getTopRight());
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// Check the sizes
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float estimatedModuleCount = (dA + dB) / (p1.getEstimatedModuleSize() * 2.0f);
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if (estimatedModuleCount > MAX_MODULE_COUNT_PER_EDGE ||
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estimatedModuleCount < MIN_MODULE_COUNT_PER_EDGE) {
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continue;
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}
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// Calculate the difference of the edge lengths in percent
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float vABBC = Math.abs((dA - dB) / Math.min(dA, dB));
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if (vABBC >= 0.1f) {
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continue;
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}
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// Calculate the diagonal length by assuming a 90° angle at topleft
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float dCpy = (float) Math.sqrt((double) dA * dA + (double) dB * dB);
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// Compare to the real distance in %
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float vPyC = Math.abs((dC - dCpy) / Math.min(dC, dCpy));
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if (vPyC >= 0.1f) {
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continue;
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}
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// All tests passed!
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results.add(test);
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}
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}
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}
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if (!results.isEmpty()) {
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return results.toArray(EMPTY_FP_2D_ARRAY);
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}
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// Nothing found!
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throw NotFoundException.getNotFoundInstance();
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}
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public FinderPatternInfo[] findMulti(Map<DecodeHintType,?> hints) throws NotFoundException {
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boolean tryHarder = hints != null && hints.containsKey(DecodeHintType.TRY_HARDER);
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BitMatrix image = getImage();
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int maxI = image.getHeight();
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int maxJ = image.getWidth();
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// We are looking for black/white/black/white/black modules in
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// 1:1:3:1:1 ratio; this tracks the number of such modules seen so far
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// Let's assume that the maximum version QR Code we support takes up 1/4 the height of the
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// image, and then account for the center being 3 modules in size. This gives the smallest
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// number of pixels the center could be, so skip this often. When trying harder, look for all
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// QR versions regardless of how dense they are.
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int iSkip = (3 * maxI) / (4 * MAX_MODULES);
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if (iSkip < MIN_SKIP || tryHarder) {
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iSkip = MIN_SKIP;
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}
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int[] stateCount = new int[5];
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for (int i = iSkip - 1; i < maxI; i += iSkip) {
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// Get a row of black/white values
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clearCounts(stateCount);
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int currentState = 0;
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for (int j = 0; j < maxJ; j++) {
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if (image.get(j, i)) {
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// Black pixel
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if ((currentState & 1) == 1) { // Counting white pixels
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currentState++;
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}
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stateCount[currentState]++;
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} else { // White pixel
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if ((currentState & 1) == 0) { // Counting black pixels
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if (currentState == 4) { // A winner?
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if (foundPatternCross(stateCount) && handlePossibleCenter(stateCount, i, j)) { // Yes
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// Clear state to start looking again
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currentState = 0;
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clearCounts(stateCount);
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} else { // No, shift counts back by two
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shiftCounts2(stateCount);
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currentState = 3;
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}
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} else {
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stateCount[++currentState]++;
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}
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} else { // Counting white pixels
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stateCount[currentState]++;
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}
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}
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} // for j=...
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if (foundPatternCross(stateCount)) {
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handlePossibleCenter(stateCount, i, maxJ);
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}
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} // for i=iSkip-1 ...
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FinderPattern[][] patternInfo = selectMultipleBestPatterns();
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List<FinderPatternInfo> result = new ArrayList<>();
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for (FinderPattern[] pattern : patternInfo) {
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ResultPoint.orderBestPatterns(pattern);
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result.add(new FinderPatternInfo(pattern));
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}
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if (result.isEmpty()) {
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return EMPTY_RESULT_ARRAY;
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} else {
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return result.toArray(EMPTY_RESULT_ARRAY);
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}
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}
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}
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