PDF417Reader.cpp Example File

 // -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
 /*
  * 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 <zxing/pdf417/PDF417Reader.h>
 #include <zxing/pdf417/detector/Detector.h>

 using zxing::Ref;
 using zxing::Result;
 using zxing::BitMatrix;
 using zxing::pdf417::PDF417Reader;
 using zxing::pdf417::detector::Detector;

 // VC++
 using zxing::ArrayRef;
 using zxing::BinaryBitmap;
 using zxing::DecodeHints;

 Ref<Result> PDF417Reader::decode(Ref<BinaryBitmap> image, DecodeHints hints) {
   Ref<DecoderResult> decoderResult;
   /* 2012-05-30 hfn C++ DecodeHintType does not yet know a type "PURE_BARCODE", */
   /* therefore skip this for now, todo: may be add this type later */
   /*
     if (!hints.isEmpty() && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
     BitMatrix bits = extractPureBits(image.getBlackMatrix());
     decoderResult = decoder.decode(bits);
     points = NO_POINTS;
     } else {
   */
   Detector detector(image);
   Ref<DetectorResult> detectorResult = detector.detect(hints); /* 2012-09-17 hints ("try_harder") */
   ArrayRef< Ref<ResultPoint> > points(detectorResult->getPoints());

   if (!hints.isEmpty()) {
     Ref<ResultPointCallback> rpcb = hints.getResultPointCallback();
     /* .get(DecodeHintType.NEED_RESULT_POINT_CALLBACK); */
     if (rpcb != NULL) {
       for (int i = 0; i < points->size(); i++) {
         rpcb->foundPossibleResultPoint(*points[i]);
       }
     }
   }
   decoderResult = decoder.decode(detectorResult->getBits(),hints);
   /*
     }
   */
   Ref<Result> r(new Result(decoderResult->getText(), decoderResult->getRawBytes(), points,
                            BarcodeFormat::PDF_417));
   return r;
 }

 void PDF417Reader::reset() {
   // do nothing
 }

 Ref<BitMatrix> PDF417Reader::extractPureBits(Ref<BitMatrix> image) {
   ArrayRef<int> leftTopBlack = image->getTopLeftOnBit();
   ArrayRef<int> rightBottomBlack = image->getBottomRightOnBit();
   /* see BitMatrix::getTopLeftOnBit etc.:
      if (leftTopBlack == null || rightBottomBlack == null) {
      throw NotFoundException.getNotFoundInstance();
      } */

   int nModuleSize = moduleSize(leftTopBlack, image);

   int top = leftTopBlack[1];
   int bottom = rightBottomBlack[1];
   int left = findPatternStart(leftTopBlack[0], top, image);
   int right = findPatternEnd(leftTopBlack[0], top, image);

   int matrixWidth = (right - left + 1) / nModuleSize;
   int matrixHeight = (bottom - top + 1) / nModuleSize;
   if (matrixWidth <= 0 || matrixHeight <= 0) {
     throw NotFoundException("PDF417Reader::extractPureBits: no matrix found!");
   }

   // Push in the "border" by half the module width so that we start
   // sampling in the middle of the module. Just in case the image is a
   // little off, this will help recover.
   int nudge = nModuleSize >> 1;
   top += nudge;
   left += nudge;

   // Now just read off the bits
   Ref<BitMatrix> bits(new BitMatrix(matrixWidth, matrixHeight));
   for (int y = 0; y < matrixHeight; y++) {
     int iOffset = top + y * nModuleSize;
     for (int x = 0; x < matrixWidth; x++) {
       if (image->get(left + x * nModuleSize, iOffset)) {
         bits->set(x, y);
       }
     }
   }
   return bits;
 }

 int PDF417Reader::moduleSize(ArrayRef<int> leftTopBlack, Ref<BitMatrix> image) {
   int x = leftTopBlack[0];
   int y = leftTopBlack[1];
   int width = image->getWidth();
   while (x < width && image->get(x, y)) {
     x++;
   }
   if (x == width) {
     throw NotFoundException("PDF417Reader::moduleSize: not found!");
   }

   int moduleSize = (int)(((unsigned)(x - leftTopBlack[0])) >> 3); // We've crossed left first bar, which is 8x
   if (moduleSize == 0) {
     throw NotFoundException("PDF417Reader::moduleSize: is zero!");
   }

   return moduleSize;
 }

 int PDF417Reader::findPatternStart(int x, int y, Ref<BitMatrix> image) {
   int width = image->getWidth();
   int start = x;
   // start should be on black
   int transitions = 0;
   bool black = true;
   while (start < width - 1 && transitions < 8) {
     start++;
     bool newBlack = image->get(start, y);
     if (black != newBlack) {
       transitions++;
     }
     black = newBlack;
   }
   if (start == width - 1) {
     throw NotFoundException("PDF417Reader::findPatternStart: no pattern start found!");
   }
   return start;
 }

 int PDF417Reader::findPatternEnd(int x, int y, Ref<BitMatrix> image) {
   int width = image->getWidth();
   int end = width - 1;
   // end should be on black
   while (end > x && !image->get(end, y)) {
     end--;
   }
   int transitions = 0;
   bool black = true;
   while (end > x && transitions < 9) {
     end--;
     bool newBlack = image->get(end, y);
     if (black != newBlack) {
       transitions++;
     }
     black = newBlack;
   }
   if (end == x) {
     throw NotFoundException("PDF417Reader::findPatternEnd: no pattern end found!");
   }
   return end;
 }