[Matplotlib-users] Plotting speed and error when calling update() using TkAgg

[Hjalmar T. <htu...@gm...>]

Hi all,


I made a little video player using matplotlib. I need it to allow very good
control over the playback speed (e.g. direction, frame-by-frame stepping
and fast and slow).

However, it's not very fast. Max frame rate I can achieve is 10-20 fps.
I followed Basti's advice on speeding up plotting (
http://bastibe.de/2013-05-30-speeding-up-matplotlib.html).
This resulted in a more than 2x improvement (from <5 to 10-20 fps), but I
would like to reach 40-50 fps.

The core code is something like this:

self.im.set_data(self.video_frame)

self.text.set_text('some text')

     self.ax.draw_artist(self.im)
     self.ax.draw_artist(self.text)
     self.im.figure.canvas.update()
     self.im.figure.canvas.flush_events()

video_frame is a 200 x 250 array. I tried lowering dpi from 100 to 50, but
the improvement is marginal.

I saw that Harden (
http://www.swharden.com/wp/2013-04-15-fixing-slow-matplotlib-in-pythonxy/)
recommended using TkAgg over Qt4Agg since TkAgg is supposed to be faster.
But, TkAgg doesn't play nicely with figure.canvas.update(). I get the
following error:
AttributeError: 'FigureCanvasTkAgg' object has no attribute 'update'
It works with Qt4Agg though.

Does anyone have a fix for this? Or some general advice on how to speed up
playback speed?

I tried with both matplotlib 1.5.1 and the current version from
github 2.0.0b4+2373.gb34c55d

Best regards,
Hjalmar