anchor.diff:      }
   
       // fixed module
  -    _modules[_moduleCount - 8][8] = (!test);
  +    _modules[moduleCount - 8][8] = (!test);
   
     }
   
     void _mapData(List<int> data, maskPattern) {
       var inc = -1;
  -    var row = _moduleCount - 1;
  +    var row = moduleCount - 1;
       var bitIndex = 7;
       var byteIndex = 0;
   
  -    for (var col = _moduleCount - 1; col > 0; col -= 2) {
  +    for (var col = moduleCount - 1; col > 0; col -= 2) {
   
         if (col == 6) col--;
   
  
positive.code: 
      for (int i = 0; i < 18; i++) {
        final bool mod = (!test && ((bits >> i) & 1) == 1);
        _modules[i ~/ 3][i % 3 + _moduleCount - 8 - 3] = mod;
      }
  
      for (int i = 0; i < 18; i++) {
        final bool mod = (!test && ((bits >> i) & 1) == 1);
        _modules[i % 3 + _moduleCount - 8 - 3][i ~/ 3] = mod;
      }
    }
  
  
negative.code:       } else if (i < 8) {
          _modules[i + 1][8] = mod;
        } else {
          _modules[moduleCount - 15 + i][8] = mod;
        }
      }
  
  