When run with python test.py, the following seems to work for me:
import matplotlib.pyplot as plt
import Tkinter, tkFileDialog
root = Tkinter.Tk()
root.withdraw()
file_path = tkFileDialog.askopenfilename()
root.destroy()
print file_path
x = range(10)
plt.plot(x)
plt.show()
I think it works because the Tk instance for the file dialog is destroyed before matplotlib fires up its own. Interestingly, it also works for me when run from
ipython --pylab=tk
where I would have expected a problem with starting the event loop twice. The canonical solution in this case would be to check if Tk is already running before firing it up (again).
I'm on MacOSX 10.7.5, custom built matplotlib (shouldn't matter).
The only thing I noticed was that after experimenting with this, the touchpad swipe gestures on my Mac no longer work... Looking into this.
Edit
Here is a breakdown of the Tk commands executed by tkFileDialog.askopenfilename():
# breakdown of tkFileDialog.askopenfilename()
import Tkinter as Tk
window = Tk.Tk()
window.withdraw()
w = Tk.Frame(window)
s = w.tk.call('tk_getOpenFile', *w._options({}))
print s
w.destroy()
window.destroy()
When I run this (with python test.py), I get the file open dialog, where I can choose a file. Upon "OK" it prints the file name and exits. This works every time on my system. However, sometimes the 3-finger gestures on my touchpad stop working while running this program! And they don't come back after the program exits!! Not even after I kill the terminal the program was running in!!!
The only way I found to bring them back is to add the following matplotlib code to test.py:
import matplotlib
matplotlib.use('tkagg')
import matplotlib.pyplot as plt
plt.figure() # simplified from plt.plot(range(10))
plt.show()
and then click on the title bar of "Figure 1". This instantly brings back the 3-finger gestures. I suspect this is simply a bug in Tkinter. (I'm on Tcl/Tk 8.5, by the way)
I cannot reproduce the behavior that the file open dialog is constantly relaunched on my system.
Could you please describe what happens on your system if you launch test.py, without any matplotlib commands?
Alternatively, since Tkinter is old and apparently buggy, may I suggest to use Qt instead? Not only does it look much nicer, it is also snappier and I didn't have any problems with bugs.
Edit 2
I have broken down the Tk actions that matplotlib takes when executing the above commands in a non-interactive environment (i.e. with python test.py and not from iPython). These are the essential backend calls:
import matplotlib.backends.backend_tkagg as backend
figManager = backend.new_figure_manager(1)
figManager.show()
backend.show.mainloop()
These are still backend independent. I.e., for a Qt figure, simply use:
import matplotlib.backends.backend_qt4agg as backend
If we break this down further to the backend-specific layer, we have:
import matplotlib.backends.backend_tkagg as backend
import Tkinter as Tk
window = Tk.Tk()
window.withdraw()
# uncomment this to use the same Tk instance for tkFileDialog and matplotlib
#import tkFileDialog
#fname = tkFileDialog.askopenfilename(master=window)
#print fname
# figManager = backend.new_figure_manager(1)
from matplotlib.figure import Figure
figure = Figure()
canvas = backend.FigureCanvasTkAgg(figure, master=window)
figManager = backend.FigureManagerTkAgg(canvas, 1, window)
# figManager.show()
window.deiconify()
# backend.show.mainloop()
Tk.mainloop()
First, run with the tkFileDialog calls commented out and check if the matplotlib figure appears and behaves correctly. Then uncomment the tkFileDialog calls and see if you finally get the expected behavior.
If not, one has to continue breaking down FigureCanvasTkAgg and FigureManagerTkAgg to understand what is going on...
Edit 3
OK, since the problem persisted, let's break down matplotlib's Tk calls even further. The following code completely isolates all of matplotlib's Tk actions that I consider essential (so it is no longer necessary to import anything from matplotlib!). Note that I left out generating the toolbar and assigning lots of callbacks and keypress events. If the code below works now, then the problem lies with these. If it doesn't work, we can conclude that it is purely a Tk problem, and most likely a bug that should be reported. Here is the code:
import Tkinter as Tk
window = Tk.Tk()
window.withdraw()
# uncomment this to use the same Tk instance for tkFileDialog and matplotlib
#w = Tk.Frame(window)
#fname = w.tk.call('tk_getOpenFile', *w._options({}))
#print fname
#w.destroy()
# canvas = backend.FigureCanvasTkAgg(figure, master=window)
_tkcanvas = Tk.Canvas(master=window, width=640, height=480, borderwidth=4)
_tkphoto = Tk.PhotoImage(master=_tkcanvas, width=640, height=480)
_tkcanvas.create_image(320, 240, image=_tkphoto)
_tkcanvas.focus_set()
# figManager = backend.FigureManagerTkAgg(canvas, 1, window)
window.wm_title("Figure 1")
window.minsize(480, 360)
_tkcanvas.pack(side=Tk.TOP, fill=Tk.BOTH, expand=1)
# figManager.show()
window.deiconify()
# backend.show.mainloop()
Tk.mainloop()
Please play around with commenting out some lines and see if you can get it working correctly. If not, I would conclude that this is a bug in Tkinter, which should be reported.
