Tkinter Matplotlib, backend conflict?

问题

I'm quite new to python but I've spent my last week trying to code a software to visualize some weavy thingy.

The basic cinematic is: the user enters every information needed into a GUI then click proceed and I have an other big function to genereate all the graphics.

This was working but the problem was that when I ran the function, which lasts like 2 minutes, the tkinter window was freezing. I read that I should use threads. Then I found this: http://uucode.com/texts/pylongopgui/pyguiapp.html This is an example that basicaly does what I want plus some other things.

I'm now trying to adapt my code to make it fit this.

And here is my problem: everything seems to work fine except that at one moment in my function a new window called "tk" pop up and everything freeze.

Everything freeze at this moment:

# On trace les fils de chaine
for i in range(0, Couches_Trame + 1):
    t = np.arange(0, np.pi, 0.1)
    plt.figure(i)
    plt.title('Plan de Trame ' + str(i+1), fontsize = '16')
    ax = plt.gca()
    ax.yaxis.set_visible(False)
    ax.xaxis.set_visible(False)
    plt.axis([-1, Plans, Fils_Chaine + 1, -1])
    for j in range(0,Plans):
        for k in range(0,Fils_Chaine):
            plt.fill_between(np.cos(t)/8+j, np.sin(t+np.pi)/8+k+0.5, \
            np.sin(t)/8+k+0.5, color='r')
    plt.savefig('Blabla'+int(i))
plt.figure(Couches_Trame)
plt.title('Plan de Trame: Projection')

When I run it directly without using Tkinter everything works fine so I have no idea what's causing this.

Also I've tried replacing this piece of code by and infinite loop like this:

i=1
while i > 0:
    i=i+1
    print(i)

This works and nothing is freezing. But then I tried this:

i=1
while i > 0:
    i=i+1
    plt.plot((i,i))

And everything freezes and the window called "tk" pop-up and instantly freezes.

I read somewhere that this could be a conflict beetwen Tkinter and matplotlib backend but that's all and this didn't help me much.

Edit: I don't know if this help but I'm using Python Portble 2.7.2.1

回答1:

I can't write comments, but a few things to check would be:

on the python cmdline, try plotting a very simply graph. E.g.:
```
>>> import pyplot
>>> pyplot.plot([1,3,1,3,1])
```

My guess is that that will show a TK window, but then stalls.

see if Tkinter actually works. try for example:

>>> import Tkinter
>>> import _tkinter
>>> Tkinter._test()

The last command should show a little window with buttons.

Also, you don't really specify what you mean by "freeze":

does your system lock up completely?
does the script lock up? Or can you close the window and the scripts simply stops?
is something being drawn, or just an empty TK window pops up?

On the other hand, since you mention threads, you may have run into the general GUI issue: a GUI waits for user input. If you want it to wait for that, and in the mean time do calculations, the latter indeed have to be in a separate thread. Then again, if you want to update your graph each time the new figure has been calculated, there shouldn't be any need for that. See e.g. http://matplotlib.sourceforge.net/examples/animation/simple_anim_tkagg.html

Lastly, it may help if you specify your OS, if it comes to debugging your setup. And I assume Python Portble is Portable Python.

回答2:

Try closing matplotlib plotting before opening a Tkinter window:

plt.close()
tk = Tkinter()
...

It works for me.

来源：https://stackoverflow.com/questions/9789777/tkinter-matplotlib-backend-conflict

标签

python

matplotlib

tkinter