zoomToSingleAxis method
Change the zoom level of an appropriate axis. Here, you need to pass axis, zoom factor, zoom position of the zoom level that needs to be modified.
Implementation
void zoomToSingleAxis(
ChartAxis axiss, double zoomPosition, double zoomFactor) {
final dynamic axis = axiss;
axis._zoomFactor = zoomFactor;
axis._zoomPosition = zoomPosition;
_chart._chartState._redraw();
}