Question

In matplotlib, I keep a reference on an axis. I want to open a new figure if the window that contain the axis have been closed. The idea is to keep adding plots on the figure, until it is closed, then I open a new figure.
Note that the creation of new plots is triggered by an event in another figure.

If it can help you to understand what I am trying to do, here is the class:

class DetailedPlot(object):
    def __init__(self, figure):
        self.origin_figure = figure

        self.axis = None
        self.print_figure = None

        self.origin_figure.canvas.mpl_connect('button_press_event', self)


    def __call__(self, event):
        if event.xdata is None or event.ydata is None:
            return
        r = round(event.xdata - 0.025, 1)
        l = round(event.ydata - 0.025, 1)
        if self.axis is None or self.axis.belongs_to_a_closed_window():
            self.print_figure = plt.figure()
            self.axis = self.print_figure.add_subplot(111)
        plotting_fcn(self.axis, r, l)

My aim to to find a function such as belongs_to_a_closed_window

Answer 1

Why not just connect a callback to the "close_event"? You could either add a ax.has_been_closed flag to the axes object or your class itself. (There are probably even cleaner solutions than a “has_been_closed” flag, depending on exactly what you’re doing… The callback function can be anything.)

import matplotlib.pyplot as plt

def on_close(event):
    event.canvas.figure.axes[0].has_been_closed = True
    print 'Closed Figure'

fig = plt.figure()
ax = fig.add_subplot(111)
ax.has_been_closed = False
ax.plot(range(10))

fig.canvas.mpl_connect('close_event', on_close)

plt.show()

print ax.has_been_closed

Edit: (Expanding on my comment below) If the OSX backend end doesn’t properly implement a close event, you could also do something like this:

import matplotlib.pyplot as plt

def has_been_closed(ax):
    fig = ax.figure.canvas.manager
    active_fig_managers = plt._pylab_helpers.Gcf.figs.values()
    return fig not in active_fig_managers

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(range(10))

print has_been_closed(ax)

plt.show()

print has_been_closed(ax)