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Animations with matplotlib?

John Hunter jdhunter at ace.bsd.uchicago.edu
Wed Nov 26 07:48:31 EST 2003 
>>>>> "Pekko" == Pekko Piirola <pekko.piirola at helsinki.fi> writes:

    Pekko> I'm trying to make an animation with matplotlib.  The
    Pekko> problem: whenever I try to rescale or move the plot with
    Pekko> the buttons of plotting window, the animation stops.  My
    Pekko> system is Debian Woody and python-2.3 with matplotlib-0.32.
    Pekko> I'm a total newbie with matplotlib (I installed it
    Pekko> yesterday), so what am I doing wrong?  An example code
    Pekko> below:

Cute code, looks like the beginnings of a digital oscilloscope....

You have discovered a bug.  The Lines2D class goes to great pains to
not plot data outside the view limits and caches a 'clipped' version
of the data set.  This cache should have been cleared by the set_data
method.  Since set_data is rarely used directly, this bug hasn't been
reported before.  It's an easy fix.

In the matplotlib.lines.py module, go to the Line2D.set_data method
(line 74 in the 0.32 release) and replace it with:

    def set_data(self, x, y):
        try: del self._xc, self._yc
        except AttributeError: pass

        self._x = asarray(x, Float)
        self._y = asarray(y, Float)
        if len(self._y)==1 and len(self._x)>1:
            self._y = self._y*ones(self._x.shape, Float)

        self._xsorted = self._is_sorted(self._x)

The important change is the addition of the first two lines, which
delete the cached instances of the clipped data.

Thanks for the bug report!
John Hunter
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