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Diffstat (limited to 'libraries/zxing/src/com/google/zxing/qrcode/detector/Detector.java')
| -rw-r--r-- | libraries/zxing/src/com/google/zxing/qrcode/detector/Detector.java | 406 |
1 files changed, 0 insertions, 406 deletions
diff --git a/libraries/zxing/src/com/google/zxing/qrcode/detector/Detector.java b/libraries/zxing/src/com/google/zxing/qrcode/detector/Detector.java deleted file mode 100644 index 724d39d59..000000000 --- a/libraries/zxing/src/com/google/zxing/qrcode/detector/Detector.java +++ /dev/null @@ -1,406 +0,0 @@ -/* - * 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.FormatException; -import com.google.zxing.NotFoundException; -import com.google.zxing.ResultPoint; -import com.google.zxing.ResultPointCallback; -import com.google.zxing.common.BitMatrix; -import com.google.zxing.common.DetectorResult; -import com.google.zxing.common.GridSampler; -import com.google.zxing.common.PerspectiveTransform; -import com.google.zxing.qrcode.decoder.Version; - -import java.util.Hashtable; - -/** - * <p>Encapsulates logic that can detect a QR Code in an image, even if the QR Code - * is rotated or skewed, or partially obscured.</p> - * - * @author Sean Owen - */ -public class Detector { - - private final BitMatrix image; - private ResultPointCallback resultPointCallback; - - public Detector(BitMatrix image) { - this.image = image; - } - - protected BitMatrix getImage() { - return image; - } - - protected ResultPointCallback getResultPointCallback() { - return resultPointCallback; - } - - /** - * <p>Detects a QR Code in an image, simply.</p> - * - * @return {@link DetectorResult} encapsulating results of detecting a QR Code - * @throws NotFoundException if no QR Code can be found - */ - public DetectorResult detect() throws NotFoundException, FormatException { - return detect(null); - } - - /** - * <p>Detects a QR Code in an image, simply.</p> - * - * @param hints optional hints to detector - * @return {@link NotFoundException} encapsulating results of detecting a QR Code - * @throws NotFoundException if QR Code cannot be found - * @throws FormatException if a QR Code cannot be decoded - */ - public DetectorResult detect(Hashtable hints) throws NotFoundException, FormatException { - - resultPointCallback = hints == null ? null : - (ResultPointCallback) hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK); - - FinderPatternFinder finder = new FinderPatternFinder(image, resultPointCallback); - FinderPatternInfo info = finder.find(hints); - - return processFinderPatternInfo(info); - } - - protected DetectorResult processFinderPatternInfo(FinderPatternInfo info) - throws NotFoundException, FormatException { - - FinderPattern topLeft = info.getTopLeft(); - FinderPattern topRight = info.getTopRight(); - FinderPattern bottomLeft = info.getBottomLeft(); - - float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft); - if (moduleSize < 1.0f) { - throw NotFoundException.getNotFoundInstance(); - } - int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize); - Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension); - int modulesBetweenFPCenters = provisionalVersion.getDimensionForVersion() - 7; - - AlignmentPattern alignmentPattern = null; - // Anything above version 1 has an alignment pattern - if (provisionalVersion.getAlignmentPatternCenters().length > 0) { - - // Guess where a "bottom right" finder pattern would have been - float bottomRightX = topRight.getX() - topLeft.getX() + bottomLeft.getX(); - float bottomRightY = topRight.getY() - topLeft.getY() + bottomLeft.getY(); - - // Estimate that alignment pattern is closer by 3 modules - // from "bottom right" to known top left location - float correctionToTopLeft = 1.0f - 3.0f / (float) modulesBetweenFPCenters; - int estAlignmentX = (int) (topLeft.getX() + correctionToTopLeft * (bottomRightX - topLeft.getX())); - int estAlignmentY = (int) (topLeft.getY() + correctionToTopLeft * (bottomRightY - topLeft.getY())); - - // Kind of arbitrary -- expand search radius before giving up - for (int i = 4; i <= 16; i <<= 1) { - try { - alignmentPattern = findAlignmentInRegion(moduleSize, - estAlignmentX, - estAlignmentY, - (float) i); - break; - } catch (NotFoundException re) { - // try next round - } - } - // If we didn't find alignment pattern... well try anyway without it - } - - PerspectiveTransform transform = - createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension); - - BitMatrix bits = sampleGrid(image, transform, dimension); - - ResultPoint[] points; - if (alignmentPattern == null) { - points = new ResultPoint[]{bottomLeft, topLeft, topRight}; - } else { - points = new ResultPoint[]{bottomLeft, topLeft, topRight, alignmentPattern}; - } - return new DetectorResult(bits, points); - } - - public static PerspectiveTransform createTransform(ResultPoint topLeft, - ResultPoint topRight, - ResultPoint bottomLeft, - ResultPoint alignmentPattern, - int dimension) { - float dimMinusThree = (float) dimension - 3.5f; - float bottomRightX; - float bottomRightY; - float sourceBottomRightX; - float sourceBottomRightY; - if (alignmentPattern != null) { - bottomRightX = alignmentPattern.getX(); - bottomRightY = alignmentPattern.getY(); - sourceBottomRightX = sourceBottomRightY = dimMinusThree - 3.0f; - } else { - // Don't have an alignment pattern, just make up the bottom-right point - bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX(); - bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY(); - sourceBottomRightX = sourceBottomRightY = dimMinusThree; - } - - return PerspectiveTransform.quadrilateralToQuadrilateral( - 3.5f, - 3.5f, - dimMinusThree, - 3.5f, - sourceBottomRightX, - sourceBottomRightY, - 3.5f, - dimMinusThree, - topLeft.getX(), - topLeft.getY(), - topRight.getX(), - topRight.getY(), - bottomRightX, - bottomRightY, - bottomLeft.getX(), - bottomLeft.getY()); - } - - private static BitMatrix sampleGrid(BitMatrix image, - PerspectiveTransform transform, - int dimension) throws NotFoundException { - - GridSampler sampler = GridSampler.getInstance(); - return sampler.sampleGrid(image, dimension, dimension, transform); - } - - /** - * <p>Computes the dimension (number of modules on a size) of the QR Code based on the position - * of the finder patterns and estimated module size.</p> - */ - protected static int computeDimension(ResultPoint topLeft, - ResultPoint topRight, - ResultPoint bottomLeft, - float moduleSize) throws NotFoundException { - int tltrCentersDimension = round(ResultPoint.distance(topLeft, topRight) / moduleSize); - int tlblCentersDimension = round(ResultPoint.distance(topLeft, bottomLeft) / moduleSize); - int dimension = ((tltrCentersDimension + tlblCentersDimension) >> 1) + 7; - switch (dimension & 0x03) { // mod 4 - case 0: - dimension++; - break; - // 1? do nothing - case 2: - dimension--; - break; - case 3: - throw NotFoundException.getNotFoundInstance(); - } - return dimension; - } - - /** - * <p>Computes an average estimated module size based on estimated derived from the positions - * of the three finder patterns.</p> - */ - protected float calculateModuleSize(ResultPoint topLeft, - ResultPoint topRight, - ResultPoint bottomLeft) { - // Take the average - return (calculateModuleSizeOneWay(topLeft, topRight) + - calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0f; - } - - /** - * <p>Estimates module size based on two finder patterns -- it uses - * {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the - * width of each, measuring along the axis between their centers.</p> - */ - private float calculateModuleSizeOneWay(ResultPoint pattern, ResultPoint otherPattern) { - float moduleSizeEst1 = sizeOfBlackWhiteBlackRunBothWays((int) pattern.getX(), - (int) pattern.getY(), - (int) otherPattern.getX(), - (int) otherPattern.getY()); - float moduleSizeEst2 = sizeOfBlackWhiteBlackRunBothWays((int) otherPattern.getX(), - (int) otherPattern.getY(), - (int) pattern.getX(), - (int) pattern.getY()); - if (Float.isNaN(moduleSizeEst1)) { - return moduleSizeEst2 / 7.0f; - } - if (Float.isNaN(moduleSizeEst2)) { - return moduleSizeEst1 / 7.0f; - } - // Average them, and divide by 7 since we've counted the width of 3 black modules, - // and 1 white and 1 black module on either side. Ergo, divide sum by 14. - return (moduleSizeEst1 + moduleSizeEst2) / 14.0f; - } - - /** - * See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of - * a finder pattern by looking for a black-white-black run from the center in the direction - * of another point (another finder pattern center), and in the opposite direction too.</p> - */ - private float sizeOfBlackWhiteBlackRunBothWays(int fromX, int fromY, int toX, int toY) { - - float result = sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY); - - // Now count other way -- don't run off image though of course - float scale = 1.0f; - int otherToX = fromX - (toX - fromX); - if (otherToX < 0) { - scale = (float) fromX / (float) (fromX - otherToX); - otherToX = 0; - } else if (otherToX > image.getWidth()) { - scale = (float) (image.getWidth() - fromX) / (float) (otherToX - fromX); - otherToX = image.getWidth(); - } - int otherToY = (int) (fromY - (toY - fromY) * scale); - - scale = 1.0f; - if (otherToY < 0) { - scale = (float) fromY / (float) (fromY - otherToY); - otherToY = 0; - } else if (otherToY > image.getHeight()) { - scale = (float) (image.getHeight() - fromY) / (float) (otherToY - fromY); - otherToY = image.getHeight(); - } - otherToX = (int) (fromX + (otherToX - fromX) * scale); - - result += sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY); - return result; - } - - /** - * <p>This method traces a line from a point in the image, in the direction towards another point. - * It begins in a black region, and keeps going until it finds white, then black, then white again. - * It reports the distance from the start to this point.</p> - * - * <p>This is used when figuring out how wide a finder pattern is, when the finder pattern - * may be skewed or rotated.</p> - */ - private float sizeOfBlackWhiteBlackRun(int fromX, int fromY, int toX, int toY) { - // Mild variant of Bresenham's algorithm; - // see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm - boolean steep = Math.abs(toY - fromY) > Math.abs(toX - fromX); - if (steep) { - int temp = fromX; - fromX = fromY; - fromY = temp; - temp = toX; - toX = toY; - toY = temp; - } - - int dx = Math.abs(toX - fromX); - int dy = Math.abs(toY - fromY); - int error = -dx >> 1; - int xstep = fromX < toX ? 1 : -1; - int ystep = fromY < toY ? 1 : -1; - - // In black pixels, looking for white, first or second time. - int state = 0; - for (int x = fromX, y = fromY; x != toX; x += xstep) { - int realX = steep ? y : x; - int realY = steep ? x : y; - - // In white pixels, looking for black. - // FIXME(dswitkin): This method seems to assume square images, which can cause these calls to - // BitMatrix.get() to throw ArrayIndexOutOfBoundsException. - if (state == 1) { - if (image.get(realX, realY)) { - state++; - } - } else { - if (!image.get(realX, realY)) { - state++; - } - } - - // Found black, white, black, and stumbled back onto white, so we're done. - if (state == 3) { - int diffX = x - fromX; - int diffY = y - fromY; - if (xstep < 0) { - diffX++; - } - return (float) Math.sqrt((double) (diffX * diffX + diffY * diffY)); - } - error += dy; - if (error > 0) { - if (y == toY) { - break; - } - y += ystep; - error -= dx; - } - } - int diffX = toX - fromX; - int diffY = toY - fromY; - return (float) Math.sqrt((double) (diffX * diffX + diffY * diffY)); - } - - /** - * <p>Attempts to locate an alignment pattern in a limited region of the image, which is - * guessed to contain it. This method uses {@link AlignmentPattern}.</p> - * - * @param overallEstModuleSize estimated module size so far - * @param estAlignmentX x coordinate of center of area probably containing alignment pattern - * @param estAlignmentY y coordinate of above - * @param allowanceFactor number of pixels in all directions to search from the center - * @return {@link AlignmentPattern} if found, or null otherwise - * @throws NotFoundException if an unexpected error occurs during detection - */ - protected AlignmentPattern findAlignmentInRegion(float overallEstModuleSize, - int estAlignmentX, - int estAlignmentY, - float allowanceFactor) - throws NotFoundException { - // Look for an alignment pattern (3 modules in size) around where it - // should be - int allowance = (int) (allowanceFactor * overallEstModuleSize); - int alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance); - int alignmentAreaRightX = Math.min(image.getWidth() - 1, estAlignmentX + allowance); - if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) { - throw NotFoundException.getNotFoundInstance(); - } - - int alignmentAreaTopY = Math.max(0, estAlignmentY - allowance); - int alignmentAreaBottomY = Math.min(image.getHeight() - 1, estAlignmentY + allowance); - if (alignmentAreaBottomY - alignmentAreaTopY < overallEstModuleSize * 3) { - throw NotFoundException.getNotFoundInstance(); - } - - AlignmentPatternFinder alignmentFinder = - new AlignmentPatternFinder( - image, - alignmentAreaLeftX, - alignmentAreaTopY, - alignmentAreaRightX - alignmentAreaLeftX, - alignmentAreaBottomY - alignmentAreaTopY, - overallEstModuleSize, - resultPointCallback); - return alignmentFinder.find(); - } - - /** - * Ends up being a bit faster than Math.round(). This merely rounds its argument to the nearest int, - * where x.5 rounds up. - */ - private static int round(float d) { - return (int) (d + 0.5f); - } -} |