anchor.diff:    /// [barIndex] is the index of our [bar], in the [LineChartData.lineBarsData] list,
     /// [spot] is the targeted spot.
     /// [spotIndex] is the index this [FlSpot], in the [LineChartBarData.spots] list.
  -  LineBarSpot(
  -    this.bar,
  -    this.barIndex,
  -    FlSpot spot,
  -    )   : spotIndex = bar.spots.indexOf(spot),
  +  LineBarSpot(LineChartBarData bar,
  +    int barIndex,
  +    FlSpot spot,)
  +    : bar = bar,
  +      barIndex = barIndex,
  +      spotIndex = bar.spots.indexOf(spot),
         super(spot.x, spot.y);
   
     /// Used for equality check, see [EquatableMixin].
  
positive.code:   /// If touch happens, [LineChart] processes it internally and
    /// passes out a list of [lineBarSpots] it gives you information about the touched spot.
    /// [touchInput] is the type of happened touch.
    LineTouchResponse(
      this.lineBarSpots,
      FlTouchInput touchInput,
    ) : super(touchInput);
  
    /// Used for equality check, see [EquatableMixin].
    @override
  
negative.code:   ///    final picture = svgRoot.toPicture()
    /// ```
    /// [width] and [height] determines the size of our picture.
    SizedPicture(Picture picture, int width, int height)
      : picture = picture,
        width = width,
        height = height;
  
    /// Used for equality check, see [EquatableMixin].
    @override
  