display `print` in callbacks in the notebook

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
n = 0

def printer(event):
    global n
    print(f'in event {event}')
    n += 1
 

fig.canvas.mpl_connect('button_press_event', printer)

when run in IPython prints out to stdout on every mouse click. In jlab + ipympl the prints don't show up anywhere I can find...

From https://ipywidgets.readthedocs.io/en/stable/examples/Output%20Widget.html it looks like this can work via:

output = widgets.Output()
display(fig.canvas, output)

n = 0
def printer(event):
    global n
    with output:
        print(f'in event {event}')
    n += 1
    
fig.canvas.mpl_connect('button_press_event', printer)

but I suspect there is a way for this to work automatically....

该 issue 提供了一个使用 fig.canvas.mpl_connect 的 Python 回调，以及一个使用 ipywidgets.Output 的变通方案；首先使用 ipympl 在 JupyterLab 中复现缺失的 print 输出，并将其与 IPython 进行比较。当 matplotlib 回调中的 print 输出无需将回调包装在 Output 上下文中即可自动显示在 notebook 中时，即表示完成。