Detects a QR Code in an image, simply.
* * @return {@link DetectorResult} encapsulating results of detecting a QR Code - * @throws ReaderException if no QR Code can be found + * @throws NotFoundException if no QR Code can be found */ - public DetectorResult detect() throws ReaderException { + public DetectorResult detect() throws NotFoundException, FormatException { return detect(null); } @@ -65,10 +66,11 @@ public class Detector { *Detects a QR Code in an image, simply.
* * @param hints optional hints to detector - * @return {@link DetectorResult} encapsulating results of detecting a QR Code - * @throws ReaderException if no QR Code can be found + * @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 ReaderException { + public DetectorResult detect(Hashtable hints) throws NotFoundException, FormatException { resultPointCallback = hints == null ? null : (ResultPointCallback) hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK); @@ -79,7 +81,8 @@ public class Detector { return processFinderPatternInfo(info); } - protected DetectorResult processFinderPatternInfo(FinderPatternInfo info) throws ReaderException { + protected DetectorResult processFinderPatternInfo(FinderPatternInfo info) + throws NotFoundException, FormatException { FinderPattern topLeft = info.getTopLeft(); FinderPattern topRight = info.getTopRight(); @@ -87,7 +90,7 @@ public class Detector { float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft); if (moduleSize < 1.0f) { - throw ReaderException.getInstance(); + throw NotFoundException.getNotFoundInstance(); } int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize); Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension); @@ -115,7 +118,7 @@ public class Detector { estAlignmentY, (float) i); break; - } catch (ReaderException re) { + } catch (NotFoundException re) { // try next round } } @@ -157,7 +160,7 @@ public class Detector { sourceBottomRightX = sourceBottomRightY = dimMinusThree; } - PerspectiveTransform transform = PerspectiveTransform.quadrilateralToQuadrilateral( + return PerspectiveTransform.quadrilateralToQuadrilateral( 3.5f, 3.5f, dimMinusThree, @@ -174,16 +177,14 @@ public class Detector { bottomRightY, bottomLeft.getX(), bottomLeft.getY()); - - return transform; } private static BitMatrix sampleGrid(BitMatrix image, PerspectiveTransform transform, - int dimension) throws ReaderException { + int dimension) throws NotFoundException { GridSampler sampler = GridSampler.getInstance(); - return sampler.sampleGrid(image, dimension, transform); + return sampler.sampleGrid(image, dimension, dimension, transform); } /** @@ -193,7 +194,7 @@ public class Detector { protected static int computeDimension(ResultPoint topLeft, ResultPoint topRight, ResultPoint bottomLeft, - float moduleSize) throws ReaderException { + 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; @@ -206,7 +207,7 @@ public class Detector { dimension--; break; case 3: - throw ReaderException.getInstance(); + throw NotFoundException.getNotFoundInstance(); } return dimension; } @@ -255,26 +256,33 @@ public class Detector { */ 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 - int otherToX = fromX - (toX - fromX); - if (otherToX < 0) { - // "to" should the be the first value not included, so, the first value off - // the edge is -1 - otherToX = -1; - } else if (otherToX > image.getWidth()) { - otherToX = image.getWidth(); - } - int otherToY = fromY - (toY - fromY); - if (otherToY < 0) { - otherToY = -1; - } else if (otherToY > image.getHeight()) { - otherToY = image.getHeight(); - } - result += sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY); - return result - 1.0f; // -1 because we counted the middle pixel twice - } + 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; + } /** *This method traces a line from a point in the image, in the direction towards another point. @@ -320,15 +328,18 @@ public class Detector { if (state == 3) { // Found black, white, black, and stumbled back onto white; done 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) { - y += ystep; - error -= dx; if (y == toY) { break; } + y += ystep; + error -= dx; } } int diffX = toX - fromX; @@ -345,24 +356,27 @@ public class Detector { * @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 ReaderException if an unexpected error occurs during detection + * @throws NotFoundException if an unexpected error occurs during detection */ protected AlignmentPattern findAlignmentInRegion(float overallEstModuleSize, int estAlignmentX, int estAlignmentY, float allowanceFactor) - throws ReaderException { + 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 ReaderException.getInstance(); + 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(