def _plot_onscroll(event, params):
    if event.key == 'control':
        if event.step < 0:
            event.key = '-'
        else:
            event.key = '+'
        _plot_onkey(event, params)
        return
    if params['butterfly']:
        return
    _plot_raw_onscroll(event, params, len(params['ch_names']))
Function to handle scroll events.
dataset/ETHPy150Open mne-tools/mne-python/mne/viz/epochs.py/_plot_onscroll