Renderer problems using Matplotlib from within a script

I've narrowed down to this call: ``` fig.canvas.tostring_argb() #fig=matplotlib.pyplot.figure() ``` this function raises an `AttributeError` when I run the code as a python script. `AttributeError: 'FigureCanvasGTKAgg' object has no attribute 'renderer'` However, this code works properly if run in the `ipython --pylab` command line. As far as I can tell from the documentation, the Agg renderer should work OK. The context is that I'm trying to make a movie from figures, without saving the frames to disk; as per this question. I'm using the approach that streams the pixel arrays to `ffmpeg` (running as a separate process) to do this, I need the `argb` array of values from the frame. Is there some configuration setting I can make to get matplotlib to work correctly from within a script? Edit Tried `use('Agg')` as per a comment; still fails; this is a minimal working example. ``` [dave@dave tools]$ python -c "import matplotlib; matplotlib.use('Agg'); import matplotlib.pyplot; fig=matplotlib.pyplot.figure(); fig.canvas.tostring_argb()" Traceback (most recent call last): File "<string>", line 1, in <module> File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_agg.py", line 416, in tostring_argb return self.renderer.tostring_argb() AttributeError: FigureCanvasAgg instance has no attribute 'renderer' ```