Matplotlib draw to plot within function immediately

Question

Is there any way to draw to a plot within a function and then have the changes show up on the plot before the function is finished executing?

For instance, in this function I would like to get the window extent of the text, but the function gives the error Cannot get window extent w/o renderer because at the time s.get_window_extent() is called the text has not been drawn on the plot.

import matplotlib.pyplot as plt
import time
plt.ion()
myfig, myax = plt.subplots()


def plot_now():
    s = myax.annotate("foo", [0.5, 0.5])
    myfig.canvas.draw_idle()
    s.get_window_extent()

plot_now()

I'm using iPython, python 2.7.6, matplotlib 1.4.3, and the Qt4Agg backend

score 1 · Accepted Answer · edited Aug 27 '15 at 20:12

1

Add plt.draw() before it goes sleep.

edited Aug 27 '15 at 20:12

Nathan Davis

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answered Aug 27 '15 at 18:52

DaveQ

1,642
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Does not work - the figure doesn't update until the function is done running – C_Z_ Aug 27 '15 at 18:55
It worked on my end running on 2.7.6 shell and matplotlib version 1.3.1 – DaveQ Aug 27 '15 at 18:58
Well, that's quite the mystery then. I wonder why it works for you but not for me, what version of MPL are you running? – C_Z_ Aug 27 '15 at 18:59
Update: This does actually work, the problem I was having was with time.sleep(), which I don't actually need. It works with new example I put up. Thanks! – C_Z_ Aug 28 '15 at 14:49

score 1 · Answer 2 · edited May 23 '17 at 12:14

1

Try plt.pause(60) instead of time.sleep(60). Someone answering this question says that time.sleep doesn't work with Qt4Agg.

edited May 23 '17 at 12:14

Community

1
1

answered Aug 27 '15 at 20:07

Amy Teegarden

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I was actually just using time.sleep() for demonstration purposes, it's not actually in my real code. I've updated my example to be closer to my actual problem – C_Z_ Aug 28 '15 at 14:32

Matplotlib draw to plot within function immediately

2 Answers2