calcMinMax method
Calculates the y-min and y-max value and the y-delta and x-delta value
Implementation
@override
void calcMinMax() {
super.calcMinMax();
_yAxis!.calculate(getData()!.getYMin2(AxisDependency.left),
getData()!.getYMax2(AxisDependency.left));
xAxis!.calculate(
0, getData()!.getMaxEntryCountSet()!.getEntryCount().toDouble());
}