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Diffstat (limited to 'libraries/zxing/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java')
| -rw-r--r-- | libraries/zxing/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java | 209 |
1 files changed, 0 insertions, 209 deletions
diff --git a/libraries/zxing/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java b/libraries/zxing/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java deleted file mode 100644 index 950a22364..000000000 --- a/libraries/zxing/src/com/google/zxing/common/detector/MonochromeRectangleDetector.java +++ /dev/null @@ -1,209 +0,0 @@ -/* - * Copyright 2009 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.common.detector; - -import com.google.zxing.NotFoundException; -import com.google.zxing.ResultPoint; -import com.google.zxing.common.BitMatrix; - -/** - * <p>A somewhat generic detector that looks for a barcode-like rectangular region within an image. - * It looks within a mostly white region of an image for a region of black and white, but mostly - * black. It returns the four corners of the region, as best it can determine.</p> - * - * @author Sean Owen - */ -public final class MonochromeRectangleDetector { - - private static final int MAX_MODULES = 32; - - private final BitMatrix image; - - public MonochromeRectangleDetector(BitMatrix image) { - this.image = image; - } - - /** - * <p>Detects a rectangular region of black and white -- mostly black -- with a region of mostly - * white, in an image.</p> - * - * @return {@link ResultPoint}[] describing the corners of the rectangular region. The first and - * last points are opposed on the diagonal, as are the second and third. The first point will be - * the topmost point and the last, the bottommost. The second point will be leftmost and the - * third, the rightmost - * @throws NotFoundException if no Data Matrix Code can be found - */ - public ResultPoint[] detect() throws NotFoundException { - int height = image.getHeight(); - int width = image.getWidth(); - int halfHeight = height >> 1; - int halfWidth = width >> 1; - int deltaY = Math.max(1, height / (MAX_MODULES << 3)); - int deltaX = Math.max(1, width / (MAX_MODULES << 3)); - - int top = 0; - int bottom = height; - int left = 0; - int right = width; - ResultPoint pointA = findCornerFromCenter(halfWidth, 0, left, right, - halfHeight, -deltaY, top, bottom, halfWidth >> 1); - top = (int) pointA.getY() - 1; - ResultPoint pointB = findCornerFromCenter(halfWidth, -deltaX, left, right, - halfHeight, 0, top, bottom, halfHeight >> 1); - left = (int) pointB.getX() - 1; - ResultPoint pointC = findCornerFromCenter(halfWidth, deltaX, left, right, - halfHeight, 0, top, bottom, halfHeight >> 1); - right = (int) pointC.getX() + 1; - ResultPoint pointD = findCornerFromCenter(halfWidth, 0, left, right, - halfHeight, deltaY, top, bottom, halfWidth >> 1); - bottom = (int) pointD.getY() + 1; - - // Go try to find point A again with better information -- might have been off at first. - pointA = findCornerFromCenter(halfWidth, 0, left, right, - halfHeight, -deltaY, top, bottom, halfWidth >> 2); - - return new ResultPoint[] { pointA, pointB, pointC, pointD }; - } - - /** - * Attempts to locate a corner of the barcode by scanning up, down, left or right from a center - * point which should be within the barcode. - * - * @param centerX center's x component (horizontal) - * @param deltaX same as deltaY but change in x per step instead - * @param left minimum value of x - * @param right maximum value of x - * @param centerY center's y component (vertical) - * @param deltaY change in y per step. If scanning up this is negative; down, positive; - * left or right, 0 - * @param top minimum value of y to search through (meaningless when di == 0) - * @param bottom maximum value of y - * @param maxWhiteRun maximum run of white pixels that can still be considered to be within - * the barcode - * @return a {@link com.google.zxing.ResultPoint} encapsulating the corner that was found - * @throws NotFoundException if such a point cannot be found - */ - private ResultPoint findCornerFromCenter(int centerX, int deltaX, int left, int right, - int centerY, int deltaY, int top, int bottom, int maxWhiteRun) throws NotFoundException { - int[] lastRange = null; - for (int y = centerY, x = centerX; - y < bottom && y >= top && x < right && x >= left; - y += deltaY, x += deltaX) { - int[] range; - if (deltaX == 0) { - // horizontal slices, up and down - range = blackWhiteRange(y, maxWhiteRun, left, right, true); - } else { - // vertical slices, left and right - range = blackWhiteRange(x, maxWhiteRun, top, bottom, false); - } - if (range == null) { - if (lastRange == null) { - throw NotFoundException.getNotFoundInstance(); - } - // lastRange was found - if (deltaX == 0) { - int lastY = y - deltaY; - if (lastRange[0] < centerX) { - if (lastRange[1] > centerX) { - // straddle, choose one or the other based on direction - return new ResultPoint(deltaY > 0 ? lastRange[0] : lastRange[1], lastY); - } - return new ResultPoint(lastRange[0], lastY); - } else { - return new ResultPoint(lastRange[1], lastY); - } - } else { - int lastX = x - deltaX; - if (lastRange[0] < centerY) { - if (lastRange[1] > centerY) { - return new ResultPoint(lastX, deltaX < 0 ? lastRange[0] : lastRange[1]); - } - return new ResultPoint(lastX, lastRange[0]); - } else { - return new ResultPoint(lastX, lastRange[1]); - } - } - } - lastRange = range; - } - throw NotFoundException.getNotFoundInstance(); - } - - /** - * Computes the start and end of a region of pixels, either horizontally or vertically, that could - * be part of a Data Matrix barcode. - * - * @param fixedDimension if scanning horizontally, this is the row (the fixed vertical location) - * where we are scanning. If scanning vertically it's the column, the fixed horizontal location - * @param maxWhiteRun largest run of white pixels that can still be considered part of the - * barcode region - * @param minDim minimum pixel location, horizontally or vertically, to consider - * @param maxDim maximum pixel location, horizontally or vertically, to consider - * @param horizontal if true, we're scanning left-right, instead of up-down - * @return int[] with start and end of found range, or null if no such range is found - * (e.g. only white was found) - */ - private int[] blackWhiteRange(int fixedDimension, int maxWhiteRun, int minDim, int maxDim, - boolean horizontal) { - - int center = (minDim + maxDim) >> 1; - - // Scan left/up first - int start = center; - while (start >= minDim) { - if (horizontal ? image.get(start, fixedDimension) : image.get(fixedDimension, start)) { - start--; - } else { - int whiteRunStart = start; - do { - start--; - } while (start >= minDim && !(horizontal ? image.get(start, fixedDimension) : - image.get(fixedDimension, start))); - int whiteRunSize = whiteRunStart - start; - if (start < minDim || whiteRunSize > maxWhiteRun) { - start = whiteRunStart; - break; - } - } - } - start++; - - // Then try right/down - int end = center; - while (end < maxDim) { - if (horizontal ? image.get(end, fixedDimension) : image.get(fixedDimension, end)) { - end++; - } else { - int whiteRunStart = end; - do { - end++; - } while (end < maxDim && !(horizontal ? image.get(end, fixedDimension) : - image.get(fixedDimension, end))); - int whiteRunSize = end - whiteRunStart; - if (end >= maxDim || whiteRunSize > maxWhiteRun) { - end = whiteRunStart; - break; - } - } - } - end--; - - return end > start ? new int[]{start, end} : null; - } - -}
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