| /* |
| * Copyright 2007 ZXing authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.zxing.qrcode.detector; |
| |
| import com.google.zxing.DecodeHintType; |
| import com.google.zxing.NotFoundException; |
| import com.google.zxing.ResultPoint; |
| import com.google.zxing.ResultPointCallback; |
| import com.google.zxing.common.BitMatrix; |
| |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * <p>This class attempts to find finder patterns in a QR Code. Finder patterns are the square |
| * markers at three corners of a QR Code.</p> |
| * |
| * <p>This class is thread-safe but not reentrant. Each thread must allocate its own object. |
| * |
| * @author Sean Owen |
| */ |
| public class FinderPatternFinder { |
| |
| private static final int CENTER_QUORUM = 2; |
| private static final EstimatedModuleComparator moduleComparator = new EstimatedModuleComparator(); |
| protected static final int MIN_SKIP = 3; // 1 pixel/module times 3 modules/center |
| protected static final int MAX_MODULES = 97; // support up to version 20 for mobile clients |
| |
| private final BitMatrix image; |
| private final List<FinderPattern> possibleCenters; |
| private boolean hasSkipped; |
| private final int[] crossCheckStateCount; |
| private final ResultPointCallback resultPointCallback; |
| |
| /** |
| * <p>Creates a finder that will search the image for three finder patterns.</p> |
| * |
| * @param image image to search |
| */ |
| public FinderPatternFinder(BitMatrix image) { |
| this(image, null); |
| } |
| |
| public FinderPatternFinder(BitMatrix image, ResultPointCallback resultPointCallback) { |
| this.image = image; |
| this.possibleCenters = new ArrayList<>(); |
| this.crossCheckStateCount = new int[5]; |
| this.resultPointCallback = resultPointCallback; |
| } |
| |
| protected final BitMatrix getImage() { |
| return image; |
| } |
| |
| protected final List<FinderPattern> getPossibleCenters() { |
| return possibleCenters; |
| } |
| |
| final FinderPatternInfo find(Map<DecodeHintType,?> hints) throws NotFoundException { |
| boolean tryHarder = hints != null && hints.containsKey(DecodeHintType.TRY_HARDER); |
| int maxI = image.getHeight(); |
| int maxJ = image.getWidth(); |
| // We are looking for black/white/black/white/black modules in |
| // 1:1:3:1:1 ratio; this tracks the number of such modules seen so far |
| |
| // Let's assume that the maximum version QR Code we support takes up 1/4 the height of the |
| // image, and then account for the center being 3 modules in size. This gives the smallest |
| // number of pixels the center could be, so skip this often. When trying harder, look for all |
| // QR versions regardless of how dense they are. |
| int iSkip = (3 * maxI) / (4 * MAX_MODULES); |
| if (iSkip < MIN_SKIP || tryHarder) { |
| iSkip = MIN_SKIP; |
| } |
| |
| boolean done = false; |
| int[] stateCount = new int[5]; |
| for (int i = iSkip - 1; i < maxI && !done; i += iSkip) { |
| // Get a row of black/white values |
| doClearCounts(stateCount); |
| int currentState = 0; |
| for (int j = 0; j < maxJ; j++) { |
| if (image.get(j, i)) { |
| // Black pixel |
| if ((currentState & 1) == 1) { // Counting white pixels |
| currentState++; |
| } |
| stateCount[currentState]++; |
| } else { // White pixel |
| if ((currentState & 1) == 0) { // Counting black pixels |
| if (currentState == 4) { // A winner? |
| if (foundPatternCross(stateCount)) { // Yes |
| boolean confirmed = handlePossibleCenter(stateCount, i, j); |
| if (confirmed) { |
| // Start examining every other line. Checking each line turned out to be too |
| // expensive and didn't improve performance. |
| iSkip = 2; |
| if (hasSkipped) { |
| done = haveMultiplyConfirmedCenters(); |
| } else { |
| int rowSkip = findRowSkip(); |
| if (rowSkip > stateCount[2]) { |
| // Skip rows between row of lower confirmed center |
| // and top of presumed third confirmed center |
| // but back up a bit to get a full chance of detecting |
| // it, entire width of center of finder pattern |
| |
| // Skip by rowSkip, but back off by stateCount[2] (size of last center |
| // of pattern we saw) to be conservative, and also back off by iSkip which |
| // is about to be re-added |
| i += rowSkip - stateCount[2] - iSkip; |
| j = maxJ - 1; |
| } |
| } |
| } else { |
| doShiftCounts2(stateCount); |
| currentState = 3; |
| continue; |
| } |
| // Clear state to start looking again |
| currentState = 0; |
| doClearCounts(stateCount); |
| } else { // No, shift counts back by two |
| doShiftCounts2(stateCount); |
| currentState = 3; |
| } |
| } else { |
| stateCount[++currentState]++; |
| } |
| } else { // Counting white pixels |
| stateCount[currentState]++; |
| } |
| } |
| } |
| if (foundPatternCross(stateCount)) { |
| boolean confirmed = handlePossibleCenter(stateCount, i, maxJ); |
| if (confirmed) { |
| iSkip = stateCount[0]; |
| if (hasSkipped) { |
| // Found a third one |
| done = haveMultiplyConfirmedCenters(); |
| } |
| } |
| } |
| } |
| |
| FinderPattern[] patternInfo = selectBestPatterns(); |
| ResultPoint.orderBestPatterns(patternInfo); |
| |
| return new FinderPatternInfo(patternInfo); |
| } |
| |
| /** |
| * Given a count of black/white/black/white/black pixels just seen and an end position, |
| * figures the location of the center of this run. |
| */ |
| private static float centerFromEnd(int[] stateCount, int end) { |
| return (end - stateCount[4] - stateCount[3]) - stateCount[2] / 2.0f; |
| } |
| |
| /** |
| * @param stateCount count of black/white/black/white/black pixels just read |
| * @return 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 |
| */ |
| protected static boolean foundPatternCross(int[] stateCount) { |
| int totalModuleSize = 0; |
| for (int i = 0; i < 5; i++) { |
| int count = stateCount[i]; |
| if (count == 0) { |
| return false; |
| } |
| totalModuleSize += count; |
| } |
| if (totalModuleSize < 7) { |
| return false; |
| } |
| float moduleSize = totalModuleSize / 7.0f; |
| float maxVariance = moduleSize / 2.0f; |
| // Allow less than 50% variance from 1-1-3-1-1 proportions |
| return |
| Math.abs(moduleSize - stateCount[0]) < maxVariance && |
| Math.abs(moduleSize - stateCount[1]) < maxVariance && |
| Math.abs(3.0f * moduleSize - stateCount[2]) < 3 * maxVariance && |
| Math.abs(moduleSize - stateCount[3]) < maxVariance && |
| Math.abs(moduleSize - stateCount[4]) < maxVariance; |
| } |
| |
| /** |
| * @param stateCount count of black/white/black/white/black pixels just read |
| * @return 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 |
| */ |
| protected static boolean foundPatternDiagonal(int[] stateCount) { |
| int totalModuleSize = 0; |
| for (int i = 0; i < 5; i++) { |
| int count = stateCount[i]; |
| if (count == 0) { |
| return false; |
| } |
| totalModuleSize += count; |
| } |
| if (totalModuleSize < 7) { |
| return false; |
| } |
| float moduleSize = totalModuleSize / 7.0f; |
| float maxVariance = moduleSize / 1.333f; |
| // Allow less than 75% variance from 1-1-3-1-1 proportions |
| return |
| Math.abs(moduleSize - stateCount[0]) < maxVariance && |
| Math.abs(moduleSize - stateCount[1]) < maxVariance && |
| Math.abs(3.0f * moduleSize - stateCount[2]) < 3 * maxVariance && |
| Math.abs(moduleSize - stateCount[3]) < maxVariance && |
| Math.abs(moduleSize - stateCount[4]) < maxVariance; |
| } |
| |
| private int[] getCrossCheckStateCount() { |
| doClearCounts(crossCheckStateCount); |
| return crossCheckStateCount; |
| } |
| |
| @Deprecated |
| protected final void clearCounts(int[] counts) { |
| doClearCounts(counts); |
| } |
| |
| @Deprecated |
| protected final void shiftCounts2(int[] stateCount) { |
| doShiftCounts2(stateCount); |
| } |
| |
| protected static void doClearCounts(int[] counts) { |
| Arrays.fill(counts, 0); |
| } |
| |
| protected static void doShiftCounts2(int[] stateCount) { |
| stateCount[0] = stateCount[2]; |
| stateCount[1] = stateCount[3]; |
| stateCount[2] = stateCount[4]; |
| stateCount[3] = 1; |
| stateCount[4] = 0; |
| } |
| |
| /** |
| * After a vertical and horizontal scan finds a potential finder pattern, this method |
| * "cross-cross-cross-checks" by scanning down diagonally through the center of the possible |
| * finder pattern to see if the same proportion is detected. |
| * |
| * @param centerI row where a finder pattern was detected |
| * @param centerJ center of the section that appears to cross a finder pattern |
| * @return true if proportions are withing expected limits |
| */ |
| private boolean crossCheckDiagonal(int centerI, int centerJ) { |
| int[] stateCount = getCrossCheckStateCount(); |
| |
| // Start counting up, left from center finding black center mass |
| int i = 0; |
| while (centerI >= i && centerJ >= i && image.get(centerJ - i, centerI - i)) { |
| stateCount[2]++; |
| i++; |
| } |
| if (stateCount[2] == 0) { |
| return false; |
| } |
| |
| // Continue up, left finding white space |
| while (centerI >= i && centerJ >= i && !image.get(centerJ - i, centerI - i)) { |
| stateCount[1]++; |
| i++; |
| } |
| if (stateCount[1] == 0) { |
| return false; |
| } |
| |
| // Continue up, left finding black border |
| while (centerI >= i && centerJ >= i && image.get(centerJ - i, centerI - i)) { |
| stateCount[0]++; |
| i++; |
| } |
| if (stateCount[0] == 0) { |
| return false; |
| } |
| |
| int maxI = image.getHeight(); |
| int maxJ = image.getWidth(); |
| |
| // Now also count down, right from center |
| i = 1; |
| while (centerI + i < maxI && centerJ + i < maxJ && image.get(centerJ + i, centerI + i)) { |
| stateCount[2]++; |
| i++; |
| } |
| |
| while (centerI + i < maxI && centerJ + i < maxJ && !image.get(centerJ + i, centerI + i)) { |
| stateCount[3]++; |
| i++; |
| } |
| if (stateCount[3] == 0) { |
| return false; |
| } |
| |
| while (centerI + i < maxI && centerJ + i < maxJ && image.get(centerJ + i, centerI + i)) { |
| stateCount[4]++; |
| i++; |
| } |
| if (stateCount[4] == 0) { |
| return false; |
| } |
| |
| return foundPatternDiagonal(stateCount); |
| } |
| |
| /** |
| * <p>After a horizontal scan finds a potential finder pattern, this method |
| * "cross-checks" by scanning down vertically through the center of the possible |
| * finder pattern to see if the same proportion is detected.</p> |
| * |
| * @param startI row where a finder pattern was detected |
| * @param centerJ center of the section that appears to cross a finder pattern |
| * @param maxCount maximum reasonable number of modules that should be |
| * observed in any reading state, based on the results of the horizontal scan |
| * @return vertical center of finder pattern, or {@link Float#NaN} if not found |
| */ |
| private float crossCheckVertical(int startI, int centerJ, int maxCount, |
| int originalStateCountTotal) { |
| BitMatrix image = this.image; |
| |
| int maxI = image.getHeight(); |
| int[] stateCount = getCrossCheckStateCount(); |
| |
| // Start counting up from center |
| int i = startI; |
| while (i >= 0 && image.get(centerJ, i)) { |
| stateCount[2]++; |
| i--; |
| } |
| if (i < 0) { |
| return Float.NaN; |
| } |
| while (i >= 0 && !image.get(centerJ, i) && stateCount[1] <= maxCount) { |
| stateCount[1]++; |
| i--; |
| } |
| // If already too many modules in this state or ran off the edge: |
| if (i < 0 || stateCount[1] > maxCount) { |
| return Float.NaN; |
| } |
| while (i >= 0 && image.get(centerJ, i) && stateCount[0] <= maxCount) { |
| stateCount[0]++; |
| i--; |
| } |
| if (stateCount[0] > maxCount) { |
| return Float.NaN; |
| } |
| |
| // Now also count down from center |
| i = startI + 1; |
| while (i < maxI && image.get(centerJ, i)) { |
| stateCount[2]++; |
| i++; |
| } |
| if (i == maxI) { |
| return Float.NaN; |
| } |
| while (i < maxI && !image.get(centerJ, i) && stateCount[3] < maxCount) { |
| stateCount[3]++; |
| i++; |
| } |
| if (i == maxI || stateCount[3] >= maxCount) { |
| return Float.NaN; |
| } |
| while (i < maxI && image.get(centerJ, i) && stateCount[4] < maxCount) { |
| stateCount[4]++; |
| i++; |
| } |
| if (stateCount[4] >= maxCount) { |
| return Float.NaN; |
| } |
| |
| // If we found a finder-pattern-like section, but its size is more than 40% different than |
| // the original, assume it's a false positive |
| int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + |
| stateCount[4]; |
| if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= 2 * originalStateCountTotal) { |
| return Float.NaN; |
| } |
| |
| return foundPatternCross(stateCount) ? centerFromEnd(stateCount, i) : Float.NaN; |
| } |
| |
| /** |
| * <p>Like {@link #crossCheckVertical(int, int, int, int)}, and in fact is basically identical, |
| * except it reads horizontally instead of vertically. This is used to cross-cross |
| * check a vertical cross check and locate the real center of the alignment pattern.</p> |
| */ |
| private float crossCheckHorizontal(int startJ, int centerI, int maxCount, |
| int originalStateCountTotal) { |
| BitMatrix image = this.image; |
| |
| int maxJ = image.getWidth(); |
| int[] stateCount = getCrossCheckStateCount(); |
| |
| int j = startJ; |
| while (j >= 0 && image.get(j, centerI)) { |
| stateCount[2]++; |
| j--; |
| } |
| if (j < 0) { |
| return Float.NaN; |
| } |
| while (j >= 0 && !image.get(j, centerI) && stateCount[1] <= maxCount) { |
| stateCount[1]++; |
| j--; |
| } |
| if (j < 0 || stateCount[1] > maxCount) { |
| return Float.NaN; |
| } |
| while (j >= 0 && image.get(j, centerI) && stateCount[0] <= maxCount) { |
| stateCount[0]++; |
| j--; |
| } |
| if (stateCount[0] > maxCount) { |
| return Float.NaN; |
| } |
| |
| j = startJ + 1; |
| while (j < maxJ && image.get(j, centerI)) { |
| stateCount[2]++; |
| j++; |
| } |
| if (j == maxJ) { |
| return Float.NaN; |
| } |
| while (j < maxJ && !image.get(j, centerI) && stateCount[3] < maxCount) { |
| stateCount[3]++; |
| j++; |
| } |
| if (j == maxJ || stateCount[3] >= maxCount) { |
| return Float.NaN; |
| } |
| while (j < maxJ && image.get(j, centerI) && stateCount[4] < maxCount) { |
| stateCount[4]++; |
| j++; |
| } |
| if (stateCount[4] >= maxCount) { |
| return Float.NaN; |
| } |
| |
| // If we found a finder-pattern-like section, but its size is significantly different than |
| // the original, assume it's a false positive |
| int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + |
| stateCount[4]; |
| if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= originalStateCountTotal) { |
| return Float.NaN; |
| } |
| |
| return foundPatternCross(stateCount) ? centerFromEnd(stateCount, j) : Float.NaN; |
| } |
| |
| /** |
| * @param stateCount reading state module counts from horizontal scan |
| * @param i row where finder pattern may be found |
| * @param j end of possible finder pattern in row |
| * @param pureBarcode ignored |
| * @return true if a finder pattern candidate was found this time |
| * @deprecated only exists for backwards compatibility |
| * @see #handlePossibleCenter(int[], int, int) |
| */ |
| @Deprecated |
| protected final boolean handlePossibleCenter(int[] stateCount, int i, int j, boolean pureBarcode) { |
| return handlePossibleCenter(stateCount, i, j); |
| } |
| |
| /** |
| * <p>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.</p> |
| * |
| * <p>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 |
| * |
| * @param stateCount reading state module counts from horizontal scan |
| * @param i row where finder pattern may be found |
| * @param j end of possible finder pattern in row |
| * @return true if a finder pattern candidate was found this time |
| */ |
| protected final boolean handlePossibleCenter(int[] stateCount, int i, int j) { |
| int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + |
| stateCount[4]; |
| float centerJ = centerFromEnd(stateCount, j); |
| float centerI = crossCheckVertical(i, (int) centerJ, stateCount[2], stateCountTotal); |
| if (!Float.isNaN(centerI)) { |
| // Re-cross check |
| centerJ = crossCheckHorizontal((int) centerJ, (int) centerI, stateCount[2], stateCountTotal); |
| if (!Float.isNaN(centerJ) && crossCheckDiagonal((int) centerI, (int) centerJ)) { |
| float estimatedModuleSize = stateCountTotal / 7.0f; |
| boolean found = false; |
| for (int index = 0; index < possibleCenters.size(); index++) { |
| FinderPattern center = possibleCenters.get(index); |
| // Look for about the same center and module size: |
| if (center.aboutEquals(estimatedModuleSize, centerI, centerJ)) { |
| possibleCenters.set(index, center.combineEstimate(centerI, centerJ, estimatedModuleSize)); |
| found = true; |
| break; |
| } |
| } |
| if (!found) { |
| FinderPattern point = new FinderPattern(centerJ, centerI, estimatedModuleSize); |
| possibleCenters.add(point); |
| if (resultPointCallback != null) { |
| resultPointCallback.foundPossibleResultPoint(point); |
| } |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * @return number of rows we could safely skip during scanning, based on the first |
| * two finder patterns that have been located. In some cases their position will |
| * allow us to infer that the third pattern must lie below a certain point farther |
| * down in the image. |
| */ |
| private int findRowSkip() { |
| int max = possibleCenters.size(); |
| if (max <= 1) { |
| return 0; |
| } |
| ResultPoint firstConfirmedCenter = null; |
| for (FinderPattern center : possibleCenters) { |
| if (center.getCount() >= CENTER_QUORUM) { |
| if (firstConfirmedCenter == null) { |
| firstConfirmedCenter = center; |
| } else { |
| // We have two confirmed centers |
| // How far down can we skip before resuming looking for the next |
| // pattern? In the worst case, only the difference between the |
| // difference in the x / y coordinates of the two centers. |
| // This is the case where you find top left last. |
| hasSkipped = true; |
| return (int) (Math.abs(firstConfirmedCenter.getX() - center.getX()) - |
| Math.abs(firstConfirmedCenter.getY() - center.getY())) / 2; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| /** |
| * @return true iff we have found at least 3 finder patterns that have been detected |
| * at least {@link #CENTER_QUORUM} times each, and, the estimated module size of the |
| * candidates is "pretty similar" |
| */ |
| private boolean haveMultiplyConfirmedCenters() { |
| int confirmedCount = 0; |
| float totalModuleSize = 0.0f; |
| int max = possibleCenters.size(); |
| for (FinderPattern pattern : possibleCenters) { |
| if (pattern.getCount() >= CENTER_QUORUM) { |
| confirmedCount++; |
| totalModuleSize += pattern.getEstimatedModuleSize(); |
| } |
| } |
| if (confirmedCount < 3) { |
| return false; |
| } |
| // OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive" |
| // and that we need to keep looking. We detect this by asking if the estimated module sizes |
| // vary too much. We arbitrarily say that when the total deviation from average exceeds |
| // 5% of the total module size estimates, it's too much. |
| float average = totalModuleSize / max; |
| float totalDeviation = 0.0f; |
| for (FinderPattern pattern : possibleCenters) { |
| totalDeviation += Math.abs(pattern.getEstimatedModuleSize() - average); |
| } |
| return totalDeviation <= 0.05f * totalModuleSize; |
| } |
| |
| /** |
| * Get square of distance between a and b. |
| */ |
| private static double squaredDistance(FinderPattern a, FinderPattern b) { |
| double x = a.getX() - b.getX(); |
| double y = a.getY() - b.getY(); |
| return x * x + y * y; |
| } |
| |
| /** |
| * @return the 3 best {@link FinderPattern}s from our list of candidates. The "best" are |
| * those have similar module size and form a shape closer to a isosceles right triangle. |
| * @throws NotFoundException if 3 such finder patterns do not exist |
| */ |
| private FinderPattern[] selectBestPatterns() throws NotFoundException { |
| |
| int startSize = possibleCenters.size(); |
| if (startSize < 3) { |
| // Couldn't find enough finder patterns |
| throw NotFoundException.getNotFoundInstance(); |
| } |
| |
| possibleCenters.sort(moduleComparator); |
| |
| double distortion = Double.MAX_VALUE; |
| FinderPattern[] bestPatterns = new FinderPattern[3]; |
| |
| for (int i = 0; i < possibleCenters.size() - 2; i++) { |
| FinderPattern fpi = possibleCenters.get(i); |
| float minModuleSize = fpi.getEstimatedModuleSize(); |
| |
| for (int j = i + 1; j < possibleCenters.size() - 1; j++) { |
| FinderPattern fpj = possibleCenters.get(j); |
| double squares0 = squaredDistance(fpi, fpj); |
| |
| for (int k = j + 1; k < possibleCenters.size(); k++) { |
| FinderPattern fpk = possibleCenters.get(k); |
| float maxModuleSize = fpk.getEstimatedModuleSize(); |
| if (maxModuleSize > minModuleSize * 1.4f) { |
| // module size is not similar |
| continue; |
| } |
| |
| double a = squares0; |
| double b = squaredDistance(fpj, fpk); |
| double c = squaredDistance(fpi, fpk); |
| |
| // sorts ascending - inlined |
| if (a < b) { |
| if (b > c) { |
| if (a < c) { |
| double temp = b; |
| b = c; |
| c = temp; |
| } else { |
| double temp = a; |
| a = c; |
| c = b; |
| b = temp; |
| } |
| } |
| } else { |
| if (b < c) { |
| if (a < c) { |
| double temp = a; |
| a = b; |
| b = temp; |
| } else { |
| double temp = a; |
| a = b; |
| b = c; |
| c = temp; |
| } |
| } else { |
| double temp = a; |
| a = c; |
| c = temp; |
| } |
| } |
| |
| // a^2 + b^2 = c^2 (Pythagorean theorem), and a = b (isosceles triangle). |
| // Since any right triangle satisfies the formula c^2 - b^2 - a^2 = 0, |
| // we need to check both two equal sides separately. |
| // The value of |c^2 - 2 * b^2| + |c^2 - 2 * a^2| increases as dissimilarity |
| // from isosceles right triangle. |
| double d = Math.abs(c - 2 * b) + Math.abs(c - 2 * a); |
| if (d < distortion) { |
| distortion = d; |
| bestPatterns[0] = fpi; |
| bestPatterns[1] = fpj; |
| bestPatterns[2] = fpk; |
| } |
| } |
| } |
| } |
| |
| if (distortion == Double.MAX_VALUE) { |
| throw NotFoundException.getNotFoundInstance(); |
| } |
| |
| return bestPatterns; |
| } |
| |
| /** |
| * <p>Orders by {@link FinderPattern#getEstimatedModuleSize()}</p> |
| */ |
| private static final class EstimatedModuleComparator implements Comparator<FinderPattern>, Serializable { |
| @Override |
| public int compare(FinderPattern center1, FinderPattern center2) { |
| return Float.compare(center1.getEstimatedModuleSize(), center2.getEstimatedModuleSize()); |
| } |
| } |
| |
| } |