[Matplotlib-users] blit example on MacOS with ipython

[pierre g. <pie...@gm...>]

Hi,
I have taken the blit example and modified it such that it runs on my mac.
The function is called blit_ex.py. It works well when I paste the code in
ipython, but it doesn't when I do "run blit_ex.py" from ipython.
I am using EPD Py25 4.1.30001_beta1 and Mac OS 10.5.

The error message is:

In [1]: run blit_ex.py
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)

/Users/pierre/Desktop/blit_ex.py in <module>()
     24     canvas.restore_region(background)
     25     line.set_ydata(np.sin(x+i/10.))
---> 26     ax.draw_artist(line)
     27     canvas.blit(ax.bbox)
     28

/Library/Frameworks/Python.framework/Versions/4.1.30001/lib/python2.5/site-packages/matplotlib-0.98.3.0001-py2.5-macosx-10.3-fat.egg/matplotlib/axes.pyc
in draw_artist(self, a)
   1532         data (axis ticks, labels, etc are not updated)
   1533         """
-> 1534         assert self._cachedRenderer is not None
   1535         a.draw(self._cachedRenderer)
   1536

AssertionError:
WARNING: Failure executing file: <blit_ex.py>

And the code is

import matplotlib.pyplot as plt
import numpy as np
import time

plt.figure(1)
plt.clf()

ax = plt.subplot(111)
canvas = ax.figure.canvas

# for profiling
tstart = time.time()

# create the initial line
x = np.linspace(-3, 3, 1000)
line, = plt.plot(x, np.sin(x), animated=True)

# save the clean slate background -- everything but the animated line
# is drawn and saved in the pixel buffer background
background = canvas.copy_from_bbox(ax.bbox)

for i in range(100):

    canvas.restore_region(background)
    line.set_ydata(np.sin(x+i/10.))
    ax.draw_artist(line)
    canvas.blit(ax.bbox)


Thanks!
Pierre