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

   1 /*
   2  *  OneDReader.cpp
   3  *  ZXing
   4  *
   5  *  Created by Lukasz Warchol on 10-01-15.
   6  *  Copyright 2010 ZXing authors All rights reserved.
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20
  21 #include "OneDReader.h"
  22 #include <zxing/ReaderException.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) {
  34                         try {
  35                                 return doDecode(image);
  36                         }catch (ReaderException re) {
  37                                 if (false /*tryHarder && image.isRotateSupported()*/) {
  38                                         /*
  39                                         BinaryBitmap rotatedImage = image.rotateCounterClockwise();
  40                                         Result result = doDecode(rotatedImage, hints);
  41                                         // Record that we found it rotated 90 degrees CCW / 270 degrees CW
  42                                         Hashtable metadata = result.getResultMetadata();
  43                                         int orientation = 270;
  44                                         if (metadata != null && metadata.containsKey(ResultMetadataType.ORIENTATION)) {
  45                                                 // But if we found it reversed in doDecode(), add in that result here:
  46                                                 orientation = (orientation +
  47                                                                            ((Integer) metadata.get(ResultMetadataType.ORIENTATION)).intValue()) % 360;
  48                                         }
  49                                         result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(orientation));
  50                                         // Update result points
  51                                         ResultPoint[] points = result.getResultPoints();
  52                                         int height = rotatedImage.getHeight();
  53                                         for (int i = 0; i < points.length; i++) {
  54                                                 points[i] = new ResultPoint(height - points[i].getY() - 1, points[i].getX());
  55                                         }
  56                                         return result;
  57                                         */
  58                                 } else {
  59                                         throw re;
  60                                 }
  61                         }
  62                 }
  63
  64                 Ref<Result> OneDReader::doDecode(Ref<BinaryBitmap> image){
  65                         int width = image->getWidth();
  66                         int height = image->getHeight();
  67                         Ref<BitArray> row(new BitArray(width));
  68 //                      BitArray row = new BitArray(width);
  69
  70                         int middle = height >> 1;
  71                         bool tryHarder = true;//hints != null && hints.containsKey(DecodeHintType.TRY_HARDER);
  72                         int rowStep = (int)fmax(1, height >> (tryHarder ? 7 : 4));
  73                         int maxLines;
  74                         if (tryHarder) {
  75                                 maxLines = height; // Look at the whole image, not just the center
  76                         } else {
  77                                 maxLines = 9; // Nine rows spaced 1/16 apart is roughly the middle half of the image
  78                         }
  79
  80                         for (int x = 0; x < maxLines; x++) {
  81
  82                                 // Scanning from the middle out. Determine which row we're looking at next:
  83                                 int rowStepsAboveOrBelow = (x + 1) >> 1;
  84                                 bool isAbove = (x & 0x01) == 0; // i.e. is x even?
  85                                 int rowNumber = middle + rowStep * (isAbove ? rowStepsAboveOrBelow : -rowStepsAboveOrBelow);
  86                                 if (rowNumber < 0 || rowNumber >= height) {
  87                                         // Oops, if we run off the top or bottom, stop
  88                                         break;
  89                                 }
  90
  91                                 // Estimate black point for this row and load it:
  92                                 try {
  93                                         row = image->getBlackRow(rowNumber, row);
  94                                 }catch (ReaderException re) {
  95                                         continue;
  96                                 }
  97
  98                                 // While we have the image data in a BitArray, it's fairly cheap to reverse it in place to
  99                                 // handle decoding upside down barcodes.
 100                                 for (int attempt = 0; attempt < 2; attempt++) {
 101                                         if (attempt == 1) { // trying again?
 102                                                 row->reverse(); // reverse the row and continue
 103                                         }
 104                                         try {
 105                                                 // Look for a barcode
 106                                                 Ref<Result> result = decodeRow(rowNumber, row);
 107                                                 // We found our barcode
 108                                                 if (attempt == 1) {
 109                                                         //                                              // But it was upside down, so note that
 110                                                         //                                              result.putMetadata(ResultMetadataType.ORIENTATION, new Integer(180));
 111                                                         //                                              // And remember to flip the result points horizontally.
 112                                                         //                                              ResultPoint[] points = result.getResultPoints();
 113                                                         //                                              points[0] = new ResultPoint(width - points[0].getX() - 1, points[0].getY());
 114                                                         //                                              points[1] = new ResultPoint(width - points[1].getX() - 1, points[1].getY());
 115                                                 }
 116                                                 return result;
 117                                         } catch (ReaderException re) {
 118                                                 // continue -- just couldn't decode this row
 119                                         }
 120                                 }
 121                         }
 122                         throw ReaderException("");
 123                 }
 124
 125                 int OneDReader::patternMatchVariance(int counters[], int countersSize, const int pattern[], int maxIndividualVariance) {
 126                         int numCounters = countersSize;
 127                         int total = 0;
 128                         int patternLength = 0;
 129                         for (int i = 0; i < numCounters; i++) {
 130                                 total += counters[i];
 131                                 patternLength += pattern[i];
 132                         }
 133                         if (total < patternLength) {
 134                                 // If we don't even have one pixel per unit of bar width, assume this is too small
 135                                 // to reliably match, so fail:
 136                                 return INT_MAX;
 137                         }
 138                         // We're going to fake floating-point math in integers. We just need to use more bits.
 139                         // Scale up patternLength so that intermediate values below like scaledCounter will have
 140                         // more "significant digits"
 141                         int unitBarWidth = (total << INTEGER_MATH_SHIFT) / patternLength;
 142                         maxIndividualVariance = (maxIndividualVariance * unitBarWidth) >> INTEGER_MATH_SHIFT;
 143
 144                         int totalVariance = 0;
 145                         for (int x = 0; x < numCounters; x++) {
 146                                 int counter = counters[x] << INTEGER_MATH_SHIFT;
 147                                 int scaledPattern = pattern[x] * unitBarWidth;
 148                                 int variance = counter > scaledPattern ? counter - scaledPattern : scaledPattern - counter;
 149                                 if (variance > maxIndividualVariance) {
 150                                         return INT_MAX;
 151                                 }
 152                                 totalVariance += variance;
 153                         }
 154                         return totalVariance / total;
 155                 }
 156
 157                 void OneDReader::recordPattern(Ref<BitArray> row, int start, int counters[], int countersCount){
 158                         int numCounters = countersCount;//sizeof(counters) / sizeof(int);
 159                         for (int i = 0; i < numCounters; i++) {
 160                                 counters[i] = 0;
 161                         }
 162                         int end = row->getSize();
 163                         if (start >= end) {
 164                                 throw ReaderException("recordPattern: start >= end");
 165                         }
 166                         bool isWhite = !row->get(start);
 167                         int counterPosition = 0;
 168                         int i = start;
 169                         while (i < end) {
 170                                 bool pixel = row->get(i);
 171                                 if (pixel ^ isWhite) { // that is, exactly one is true
 172                                         counters[counterPosition]++;
 173                                 } else {
 174                                         counterPosition++;
 175                                         if (counterPosition == numCounters) {
 176                                                 break;
 177                                         } else {
 178                                                 counters[counterPosition] = 1;
 179                                                 isWhite ^= true; // isWhite = !isWhite;
 180                                         }
 181                                 }
 182                                 i++;
 183                         }
 184                         // If we read fully the last section of pixels and filled up our counters -- or filled
 185                         // the last counter but ran off the side of the image, OK. Otherwise, a problem.
 186                         if (!(counterPosition == numCounters || (counterPosition == numCounters - 1 && i == end))) {
 187                                 throw ReaderException("recordPattern");
 188                         }
 189                 }
 190
 191                 OneDReader::~OneDReader() {
 192                 }
 193         }
 194 }