reset method
Returns the plot area back to its original position after zooming.
Implementation
void reset() {
for (int index = 0;
index < _chart._chartAxis._axisCollections.length;
index++) {
final dynamic axis = _chart._chartAxis._axisCollections[index];
axis._zoomFactor = 1.0;
axis._zoomPosition = 0.0;
}
_chart._chartState._redraw();
}