notebook with pylab=inline appears to call figure.draw twice

[bicubic]

I had to hook matplotlib.Figure.draw for unrelated reasons and noticed it gets called twice in ipython notebook. Is this intentional?

Tracing through all method calls on figure, I found that a plain python script will call

clf
set_canvas
add_axobserver
add_subplot
sca
set_size_inches
draw
get_rasterized
get_agg_filter
get_visible
get_agg_filter
get_rasterized

While notebook will call

clf
set_canvas
add_subplot
sca
get_facecolor
get_edgecolor
set_facecolor
set_edgecolor
get_facecolor
get_edgecolor
set_facecolor
set_edgecolor
draw
get_rasterized
get_agg_filter
get_visible
get_agg_filter
get_rasterized
get_tightbbox
draw
get_rasterized
get_agg_filter
get_visible
get_agg_filter
get_rasterized
set_facecolor
set_edgecolor
set_canvas
set_facecolor
set_edgecolor

You can run https://gist.github.com/tricubic/0d33d808a0d7fa7dbf22 in notebook or as a script to repeat this.

[Carreau]

Did you changed your username ?

https://gist.github.com/tricubic/0d33d808a0d7fa7dbf22

[bicubic]

Hah, sorry I did. Updated the link.

[bicubic]

This turns out to be intended, although unpleasant behavior of matplotlib\backend_bases.py:

"when bbox_inches == "tight", it saves the figure
twice. The first save command is just to estimate
the bounding box of the figure. A stringIO object is
used as a temporary file object, but it causes a
problem for some backends (ps backend with
usetex=True) if they expect a filename, not a
file-like object. As I think it is best to change
the backend to support file-like object, i'm going
to leave it as it is. However, a better solution
than stringIO seems to be needed. -JJL
result = getattr(self, method_name)"