add_event_handler#

ImageWidget.add_event_handler(handler, event='current_index')[source]#

Register an event handler.

Currently the only event that ImageWidget supports is “current_index”. This event is emitted whenever the index of the ImageWidget changes.

Parameters:

  • handler (callable) – callback function, must take a dict as the only argument. This dict will be the current_index

  • event (str, "current_index") – the only supported event is “current_index”

Example

def my_handler(index):
    print(index)
    # example prints: {"t": 100} if data has only time dimension
    # "z" index will be another key if present in the data, ex: {"t": 100, "z": 5}

# create an image widget
iw = ImageWidget(...)

# add event handler
iw.add_event_handler(my_handler)