qzxing/source/zxing/oned/OneDReader.cpp

// -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
/*
 *  OneDReader.cpp
 *  ZXing
 *
 *  Copyright 2010 ZXing authors All rights reserved.
 *
 * 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.
 */

#include "OneDReader.h"
#include <zxing/ReaderException.h>
#include <zxing/oned/OneDResultPoint.h>
#include <math.h>
#include <limits.h>

namespace zxing {
  namespace oned {
    using namespace std;

    OneDReader::OneDReader() {
    }

    Ref<Result> OneDReader::decode(Ref<BinaryBitmap> image, DecodeHints hints) {
      Ref<Result> result = doDecode(image, hints);
      if (result.empty() && hints.getTryHarder() && image->isRotateSupported()) {
        Ref<BinaryBitmap> rotatedImage(image->rotateCounterClockwise());
        result = doDecode(rotatedImage, hints);
        if (!result.empty()) {
          /*
          // Record that we found it rotated 90 degrees CCW / 270 degrees CW
          Hashtable metadata = result.getResultMetadata();
          int orientation = 270;
          if (metadata != null && metadata.containsKey(ResultMetadataType.ORIENTATION)) {
            // But if we found it reversed in doDecode(), add in that result here:
            orientation = (orientation +
                     ((Integer) metadata.get(ResultMetadataType.ORIENTATION)).intValue()) % 360;
          }
          result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(orientation));
          */
          // Update result points
          std::vector<Ref<ResultPoint> >& points (result->getResultPoints());
          int height = rotatedImage->getHeight();
          for (size_t i = 0; i < points.size(); i++) {
            points[i].reset(new OneDResultPoint(height - points[i]->getY() - 1, points[i]->getX()));
          }
        }
      }
      if (result.empty()) {
        throw ReaderException("");
      }
      return result;
    }

    Ref<Result> OneDReader::doDecode(Ref<BinaryBitmap> image, DecodeHints hints) {
      int width = image->getWidth();
      int height = image->getHeight();
      Ref<BitArray> row(new BitArray(width));
      int middle = height >> 1;
      bool tryHarder = hints.getTryHarder();
      int rowStep = (int)fmax(1, height >> (tryHarder ? 8 : 5));
      int maxLines;
      if (tryHarder) {
        maxLines = height; // Look at the whole image, not just the center
      } else {
        maxLines = 15; // 15 rows spaced 1/32 apart is roughly the middle half of the image
      }

      for (int x = 0; x < maxLines; x++) {
        // Scanning from the middle out. Determine which row we're looking at next:
        int rowStepsAboveOrBelow = (x + 1) >> 1;
        bool isAbove = (x & 0x01) == 0; // i.e. is x even?
        int rowNumber = middle + rowStep * (isAbove ? rowStepsAboveOrBelow : -rowStepsAboveOrBelow);
        if (rowNumber < 0 || rowNumber >= height) {
          // Oops, if we run off the top or bottom, stop
          break;
        }

        // Estimate black point for this row and load it:
        try {
          row = image->getBlackRow(rowNumber, row);
        } catch (ReaderException const& re) {
          continue;
        } catch (IllegalArgumentException const& re) {
          continue;
        }

        // While we have the image data in a BitArray, it's fairly cheap to reverse it in place to
        // handle decoding upside down barcodes.
        for (int attempt = 0; attempt < 2; attempt++) {
          if (attempt == 1) {
            row->reverse(); // reverse the row and continue
          }

          // Look for a barcode
          Ref<Result> result = decodeRow(rowNumber, row);
          // We found our barcode
          if (!result.empty()) {
            if (attempt == 1) {
              // But it was upside down, so note that
              // result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(180));
              // And remember to flip the result points horizontally.
              std::vector<Ref<ResultPoint> > points(result->getResultPoints());
              // if there's exactly two points (which there should be), flip the x coordinate
              // if there's not exactly 2, I don't know what do do with it
              if (points.size() == 2) {
                Ref<ResultPoint> pointZero(new OneDResultPoint(width - points[0]->getX() - 1,
                    points[0]->getY()));
                points[0] = pointZero;

                Ref<ResultPoint> pointOne(new OneDResultPoint(width - points[1]->getX() - 1,
                    points[1]->getY()));
                points[1] = pointOne;

                result.reset(new Result(result->getText(), result->getRawBytes(), points,
                    result->getBarcodeFormat()));
              }
            }
            return result;
          }
        }
      }
      return Ref<Result>();
    }

    unsigned int OneDReader::patternMatchVariance(int counters[], int countersSize,
        const int pattern[], int maxIndividualVariance) {
      int numCounters = countersSize;
      unsigned int total = 0;
      unsigned int patternLength = 0;
      for (int i = 0; i < numCounters; i++) {
        total += counters[i];
        patternLength += pattern[i];
      }
      if (total < patternLength) {
        // If we don't even have one pixel per unit of bar width, assume this is too small
        // to reliably match, so fail:
        return INT_MAX;
      }
      // We're going to fake floating-point math in integers. We just need to use more bits.
      // Scale up patternLength so that intermediate values below like scaledCounter will have
      // more "significant digits"
      unsigned int unitBarWidth = (total << INTEGER_MATH_SHIFT) / patternLength;
      maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> INTEGER_MATH_SHIFT;

      unsigned int totalVariance = 0;
      for (int x = 0; x < numCounters; x++) {
        int counter = counters[x] << INTEGER_MATH_SHIFT;
        int scaledPattern = pattern[x] * unitBarWidth;
        int variance = counter > scaledPattern ? counter - scaledPattern : scaledPattern - counter;
        if (variance > maxIndividualVariance) {
          return INT_MAX;
        }
        totalVariance += variance;
      }
      return totalVariance / total;
    }

    bool OneDReader::recordPattern(Ref<BitArray> row, int start, int counters[], int countersCount) {
      int numCounters = countersCount;//sizeof(counters) / sizeof(int);
      for (int i = 0; i < numCounters; i++) {
        counters[i] = 0;
      }
      int end = row->getSize();
      if (start >= end) {
        return false;
      }
      bool isWhite = !row->get(start);
      int counterPosition = 0;
      int i = start;
      while (i < end) {
        bool pixel = row->get(i);
        if (pixel ^ isWhite) { // that is, exactly one is true
          counters[counterPosition]++;
        } else {
          counterPosition++;
          if (counterPosition == numCounters) {
            break;
          } else {
            counters[counterPosition] = 1;
            isWhite ^= true; // isWhite = !isWhite;
          }
        }
        i++;
      }
      // If we read fully the last section of pixels and filled up our counters -- or filled
      // the last counter but ran off the side of the image, OK. Otherwise, a problem.
      if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i == end))) {
        return false;
      }
      return true;
    }

    OneDReader::~OneDReader() {
    }
  }
}