Re: [Matplotlib-users] Figures piling up in Tkinter GUI (1.2.0rc2)

[Vlastimil B. <vla...@gm...>]

2012/11/1 Hans Bering <han...@ar...>:
> Hello everybody,
>
> I'm building a small Tkinter GUI using matplotlib, in which I have to
> change/update plots quite often depending on user input (with different
> contents & sizes, in different places in the GUI, etc.; but always only
> one figure at a time).
>
> As a first resort, I regenerated the figures with plt.figure(...) whenever
> necessary; unfortunately, the program happily accumulated memory with
> every new figure until the computer would no longer cooperate in a timely
> fashion. The following minimal script should demonstrate the tendency:
>
...
> Now I am wondering if I am missing some detail, e.g., some other clean-up
> procedure? Or should this work & could be a memory leak in matplotlib or
> Tkinter? And/or is this approach (of generating a new figure every time)
> not recommended in the first place? I tried reusing the figure, but some
> aspects like changing the layout in the GUI and applying new size and dpi
> then proved tricky in their own ways.
>
> Many thanks in advance,
> Hans
>
Hi,
I'd recommend to use an embedded plot and only clear and replace its
content (rather than tu use pyplot and recreate the figure multiple
times. I believe, changing of the figure should be possible too.

see e.g. the sample for tkinter
http://matplotlib.org/examples/user_interfaces/embedding_in_tk.html

I only roughly adapted that source to use your function and the memory
usage appears to be more effective (although there is some increase
too - as displayed in Process Explorer). Would some variation of the
following work for you?

hth,
  vbr

########################################
#!/usr/bin/env python

import matplotlib
matplotlib.use('TkAgg')
import math

from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg,
NavigationToolbar2TkAgg
from matplotlib.figure import Figure

import Tkinter

root = Tkinter.Tk()
root.wm_title("Embedding in TK")

fig = Figure(figsize=(5,4), dpi=100)
ax = fig.add_subplot(111)

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.show()
canvas.get_tk_widget().pack(side=Tkinter.TOP, fill=Tkinter.BOTH, expand=1)

toolbar = NavigationToolbar2TkAgg( canvas, root )
toolbar.update()
canvas._tkcanvas.pack(side=Tkinter.TOP, fill=Tkinter.BOTH, expand=1)

plotShift = 0
def replot():
    global plotShift, a, f
    ax.clear()
    xVals = xrange(100)
    ax.plot(xVals, [math.sin(x + plotShift) for x in xVals])
    fig.canvas.draw()
    plotShift += 10

button = Tkinter.Button(master=root, text='replot', command=replot)
button.pack(side=Tkinter.BOTTOM)
Tkinter.mainloop()