`matplotlib` clickable plot in Panel row

Question

I have figured out how to make a matplotlib graph clickable so that I can click a point and create a new plot based off of metadata for that point, following the answer here.

Now it comes time to put that clickable plot in a Panel dashboard. The obvious move is to add that figure to a panel.Row. While this displays the figure, I do not get the interactivity.

import matplotlib.pyplot as plt
import panel as pn

class custom_objects_to_plot:
    def __init__(self, x, y, name):
        self.x = x
        self.y = y
        self.name = name

a = custom_objects_to_plot(10, 20, "a")
b = custom_objects_to_plot(30, 5, "b")
c = custom_objects_to_plot(40, 30, "c")
d = custom_objects_to_plot(120, 10, "d")

def on_pick(event):
    my_fig, my_ax = plt.subplots() # New plot with unique name
    my_ax.scatter([1, 2, 3, 4], [5, 6, 7, 8]) # Make the scatterplot
    my_fig.show() # Show the plot

fig, ax = plt.subplots()
for obj in [a, b, c, d]:
    artist = ax.plot(obj.x, obj.y, 'ro', picker=5)[0]
    artist.obj = obj

fig.canvas.callbacks.connect('pick_event', on_pick)

my_row = pn.Row()
my_row.append(fig)
my_row.show()

How would I get the interactive (clickable) plot to appear like how it appears when I run from the command line?

Answer 1

I am not too familiar with panel, but I found this open issue on their git:

https://github.com/holoviz/panel/issues/2349

The issue states:

I like to build interactive GUIs with matplotlib with heavy usage of matplotlibs events e.g button_press_event, motion_notify_event etc. Currently this is not possible in Panel as Matplotlib is pretty much handled as a static image that can be redrawn when it's object changes.

I also checked the docs, along with a couple new updates to the open issue, and it looks like there's some functionality added via ipympl where you can use an interactive back-end, but I don't know how fleshed out it is. I'd assume it'll look something like this, but I can test it later tonight.

fig.canvas.callbacks.connect('pick_event', on_pick)

mpl_pane = pn.pane.Matplotlib(fig, interactive=True)
my_row = pn.Row(mpl_pane)
my_row.show()

Just curious, but does it have to use panel, or will another python GUI work? I know how to do this in other python GUI frameworks.