Hello. I'm trying to embed mpl in an wxpython app which is intended
to run repeatedly within a single script. (It's a workaround for not
being able to use pyplot.show() more than once in a script.)
All seems to work as intended when I don't attach any key press events
(here to just destroy the app) to canvas, but when I do, as in the
script below, for some reason I keep getting errors that appear to
indicate that some remnant of the zombie of the previous app instance
may be sticking around when they shouldn't exist. Both the script in
question and the (typical) error message are shown below in this
message.
I've tried both on Linux (Debian Lenny) and Mac OS X (Leopard) with
Python 2.5 with the latest stable versions of numpy, matplotlib,
wxpython and whatnot. I observe similar problems on both
environments. What am I doing wrong? Am I not properly handling the
cleanup process before destroying the app at each loop? I think
wx.App.MainLoop() can be run more than once within a script, so that
should be okay, though I'm not sure if mpl is designed to be used this
way.
A strange thing is that when I close the app by clicking on the 'X' on
the Window frame, I don't reproduce the error. If anything, I wonder
how to initiate the event that imitates that behavior, but that is
probably a question for the wxpython people...
I'd appreciate any assistance!
Cheers,
Taro
BEGIN SCRIPT
#!/usr/bin/env python
import wxversion
wxversion.ensureMinimal('2.8')
import matplotlib
matplotlib.use('WXAgg')
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
from matplotlib.figure import Figure
from numpy import arange, sin, pi
import wx
class CanvasFrame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self, None, -1, 'CanvasFrame',size=(550,350))
self.figure = Figure()
self.axes = self.figure.add_subplot(111)
t = arange(0.0, 3.0, 0.01)
s = sin(2 * pi * t)
self.axes.plot(t, s)
self.canvas = FigureCanvas(self, -1, self.figure)
self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
self.canvas.mpl_connect('key_press_event', self.key_press)
self.sizer = wx.BoxSizer(wx.VERTICAL)
self.sizer.Add(self.canvas, 1, wx.LEFT | wx.TOP | wx.GROW)
self.SetSizer(self.sizer)
self.Fit()
def key_press(self, event):
self.Close(True)
def OnCloseWindow(self, event):
print 'Window Closed'
self.Destroy()
class App(wx.App):
def OnInit(self):
frame = CanvasFrame()
frame.Show(True)
return True
def run_app():
app = App(redirect=False)
app.MainLoop()
del app
for i in range(10):
run_app()
END SCRIPT
BEGIN ERROR MESSAGE
Traceback (most recent call last):
File /usr/lib/python2.5/site-packages/matplotlib/backends/backend_wx.py,
line 1316, in _onMotion
FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=evt)
File /usr/lib/python2.5/site-packages/matplotlib/backend_bases.py,
line 1244, in motion_notify_event
guiEvent=guiEvent)
File /usr/lib/python2.5/site-packages/matplotlib/backend_bases.py,
line 899, in __init__
LocationEvent.__init__(self, name, canvas, x, y, guiEvent=guiEvent)
File /usr/lib/python2.5/site-packages/matplotlib/backend_bases.py,
line 817, in __init__
self._update_enter_leave()
File /usr/lib/python2.5/site-packages/matplotlib/backend_bases.py,
line 844, in _update_enter_leave
last.canvas.callbacks.process('axes_leave_event', last)
File /usr/lib/python2.5/site-packages/wx-2.8-gtk2-unicode/wx/_core.py,
line 14314, in __getattr__
raise PyDeadObjectError(self.attrStr % self._name)
wx._core.PyDeadObjectError: The C++ part of the FigureCanvasWxAgg
object has been deleted, attribute access no longer allowed.
END ERROR MESSAGE
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