SfCartesianChart(
              plotAreaBorderWidth: 0,
              primaryXAxis: CategoryAxis(
                isVisible: true,
                labelStyle: TextStyle(color: Colors.black.withOpacity(0.0)),
                majorGridLines: MajorGridLines(width: 0),
                majorTickLines: MajorTickLines(width: 0),
                axisLine: AxisLine(color: Colors.black, width: 2),
              ),
              primaryYAxis: NumericAxis(
                isVisible: true,
                crossesAt: 0,
                numberFormat: chartYLabelFormat,
                labelStyle: chartLabel,
                axisLine: AxisLine(width: 0),
                majorGridLines: MajorGridLines(width: 2,
                    dashArray: <double>[2,2]),
                majorTickLines: MajorTickLines(
                  width: 0,
                ),
              ),
              trackballBehavior: TrackballBehavior(
                  enable: true,
                  tooltipSettings: InteractiveTooltip(
                      format: "point.x:  point.y", color: Colors.black)),
              series: getGradientAreaSeries(),
            ),