cpp/core/src/zxing/oned/OneDReader.cpp

   1 /*
   2  *  OneDReader.cpp
   3  *  ZXing
   4  *
   5  *  Copyright 2010 ZXing authors All rights reserved.
   6  *
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  */
  19
  20 #include "OneDReader.h"
  21 #include <zxing/ReaderException.h>
  22 #include <zxing/oned/OneDResultPoint.h>
  23 #include <math.h>
  24 #include <limits.h>
  25
  26 namespace zxing {
  27         namespace oned {
  28                 using namespace std;
  29
  30                 OneDReader::OneDReader() {
  31                 }
  32
  33                 Ref<Result> OneDReader::decode(Ref<BinaryBitmap> image, DecodeHints hints) {
  34                   Ref<Result> result = doDecode(image, hints);
  35                   if (result.empty() && hints.getTryHarder() && image->isRotateSupported()) {
  36                     Ref<BinaryBitmap> rotatedImage(image->rotateCounterClockwise());
  37                                 result = doDecode(rotatedImage, hints);
  38                                 if (!result.empty()) {
  39                                   /*
  40                                         // Record that we found it rotated 90 degrees CCW / 270 degrees CW
  41                                         Hashtable metadata = result.getResultMetadata();
  42                                         int orientation = 270;
  43                                         if (metadata != null && metadata.containsKey(ResultMetadataType.ORIENTATION)) {
  44                                                 // But if we found it reversed in doDecode(), add in that result here:
  45                                                 orientation = (orientation +
  46                                                                            ((Integer) metadata.get(ResultMetadataType.ORIENTATION)).intValue()) % 360;
  47                                         }
  48                                         result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(orientation));
  49                                         */
  50           // Update result points
  51                                         std::vector<Ref<ResultPoint> > points (result->getResultPoints());
  52                                         int height = rotatedImage->getHeight();
  53                                         for (size_t i = 0; i < points.size(); i++) {
  54                                                 points[i].reset(new OneDResultPoint(height - points[i]->getY() - 1, points[i]->getX()));
  55                                         }
  56                                 }
  57                   }
  58                   if (result.empty()) {
  59                     throw ReaderException("");
  60                   }
  61                   return result;
  62                 }
  63
  64                 Ref<Result> OneDReader::doDecode(Ref<BinaryBitmap> image, DecodeHints hints) {
  65                         int width = image->getWidth();
  66                         int height = image->getHeight();
  67                         Ref<BitArray> row(new BitArray(width));
  68                         int middle = height >> 1;
  69                         bool tryHarder = hints.getTryHarder();
  70                         int rowStep = (int)fmax(1, height >> (tryHarder ? 8 : 5));
  71                         int maxLines;
  72                         if (tryHarder) {
  73                                 maxLines = height; // Look at the whole image, not just the center
  74                         } else {
  75         maxLines = 15; // 15 rows spaced 1/32 apart is roughly the middle half of the image
  76                         }
  77
  78                         for (int x = 0; x < maxLines; x++) {
  79                                 // Scanning from the middle out. Determine which row we're looking at next:
  80                                 int rowStepsAboveOrBelow = (x + 1) >> 1;
  81                                 bool isAbove = (x & 0x01) == 0; // i.e. is x even?
  82                                 int rowNumber = middle + rowStep * (isAbove ? rowStepsAboveOrBelow : -rowStepsAboveOrBelow);
  83                                 if (rowNumber < 0 || rowNumber >= height) {
  84                                         // Oops, if we run off the top or bottom, stop
  85                                         break;
  86                                 }
  87
  88                                 // Estimate black point for this row and load it:
  89                                 try {
  90                                         row = image->getBlackRow(rowNumber, row);
  91                                 } catch (ReaderException re) {
  92                                         continue;
  93                                 } catch (IllegalArgumentException re) {
  94           continue;
  95                                 }
  96
  97                                 // While we have the image data in a BitArray, it's fairly cheap to reverse it in place to
  98                                 // handle decoding upside down barcodes.
  99                                 for (int attempt = 0; attempt < 2; attempt++) {
 100                                         if (attempt == 1) { // trying again?
 101                                                 row->reverse(); // reverse the row and continue
 102                                         }
 103
 104           // Look for a barcode
 105           Ref<Result> result = decodeRow(rowNumber, row);
 106           // We found our barcode
 107           if (!result.empty()) {
 108             //                                          // But it was upside down, so note that
 109             //                                          result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(180));
 110             //                                          // And remember to flip the result points horizontally.
 111             std::vector<Ref<ResultPoint> > points(result->getResultPoints());
 112             // if there's exactly two points (which there should be), flip the x coordinate
 113             // if there's not exactly 2, I don't know what do do with it
 114             if (points.size() == 2) {
 115               Ref<ResultPoint> pointZero(new OneDResultPoint(width - points[0]->getX() - 1,
 116                   points[0]->getY()));
 117               points[0] = pointZero;
 118
 119               Ref<ResultPoint> pointOne(new OneDResultPoint(width - points[1]->getX() - 1,
 120                   points[1]->getY()));
 121               points[1] = pointOne;
 122
 123               result.reset(new Result(result->getText(), result->getRawBytes(), points,
 124                   result->getBarcodeFormat()));
 125             }
 126             return result;
 127           }
 128                                 }
 129                         }
 130                         return Ref<Result>();
 131                 }
 132
 133                 unsigned int OneDReader::patternMatchVariance(int counters[], int countersSize,
 134                     const int pattern[], int maxIndividualVariance) {
 135                         int numCounters = countersSize;
 136                         unsigned int total = 0;
 137                         unsigned int patternLength = 0;
 138                         for (int i = 0; i < numCounters; i++) {
 139                                 total += counters[i];
 140                                 patternLength += pattern[i];
 141                         }
 142                         if (total < patternLength) {
 143                                 // If we don't even have one pixel per unit of bar width, assume this is too small
 144                                 // to reliably match, so fail:
 145                                 return INT_MAX;
 146                         }
 147                         // We're going to fake floating-point math in integers. We just need to use more bits.
 148                         // Scale up patternLength so that intermediate values below like scaledCounter will have
 149                         // more "significant digits"
 150                         unsigned int unitBarWidth = (total << INTEGER_MATH_SHIFT) / patternLength;
 151                         maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> INTEGER_MATH_SHIFT;
 152
 153                         unsigned int totalVariance = 0;
 154                         for (int x = 0; x < numCounters; x++) {
 155                                 int counter = counters[x] << INTEGER_MATH_SHIFT;
 156                                 int scaledPattern = pattern[x] * unitBarWidth;
 157                                 int variance = counter > scaledPattern ? counter - scaledPattern : scaledPattern - counter;
 158                                 if (variance > maxIndividualVariance) {
 159                                         return INT_MAX;
 160                                 }
 161                                 totalVariance += variance;
 162                         }
 163                         return totalVariance / total;
 164                 }
 165
 166                 bool OneDReader::recordPattern(Ref<BitArray> row, int start, int counters[], int countersCount) {
 167                         int numCounters = countersCount;//sizeof(counters) / sizeof(int);
 168                         for (int i = 0; i < numCounters; i++) {
 169                                 counters[i] = 0;
 170                         }
 171                         int end = row->getSize();
 172                         if (start >= end) {
 173                                 return false;
 174                         }
 175                         bool isWhite = !row->get(start);
 176                         int counterPosition = 0;
 177                         int i = start;
 178                         while (i < end) {
 179                                 bool pixel = row->get(i);
 180                                 if (pixel ^ isWhite) { // that is, exactly one is true
 181                                         counters[counterPosition]++;
 182                                 } else {
 183                                         counterPosition++;
 184                                         if (counterPosition == numCounters) {
 185                                                 break;
 186                                         } else {
 187                                                 counters[counterPosition] = 1;
 188                                                 isWhite ^= true; // isWhite = !isWhite;
 189                                         }
 190                                 }
 191                                 i++;
 192                         }
 193                         // If we read fully the last section of pixels and filled up our counters -- or filled
 194                         // the last counter but ran off the side of the image, OK. Otherwise, a problem.
 195                         if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i == end))) {
 196                                 return false;
 197                         }
 198                         return true;
 199                 }
 200
 201                 OneDReader::~OneDReader() {
 202                 }
 203         }
 204 }