Re: [Matplotlib-users] Animated artists not present in savefigged files

[John H. <jd...@gm...>]

On Mon, Aug 23, 2010 at 7:59 AM, Kim Hansen <sla...@gm...> wrote:
> Hi list,
>
> I am using animated artists to generate an animation, where I save each step
> in the anmantion as a png using the savefig method of the figure instance
> after drawing the animated artists on a cached background and after
> fig.canvas.blit.
>
> What I see on screen are the updated animated artists being drawn, but only
> the cached background with subplots and axes and grid is being stored in the
> savefig commands
> called after the last blit.
>
> Why is only the background saved.?

The animated property tells the figure to not draw the artist on a
call to figure.draw, which is wha savefig calls.  This enables you to
draw the background (everything but the animated artists) with a call
to figure.canvas.draw, and then selectively draw your animated artists
when you want.  It does pose a problem for saving.

The best approach is to turn off the animated property right before
saving, and turn it back on as needed.  Something like

artists = fig.get_children()

animated = dict()
for artist in artists:
    animated[artist] = artist.get_animated()
    artist.set_animated(False)

fig.savefig('myfig.png')

for artist in artists:
    artist.set_animated(animated[artist])

Also, Ryan May has been working on a nice framework for animation that may help,

http://github.com/dopplershift/Animation

JDH