[Matplotlib-users] set limits not obeyed for stacked plots when set_aspect('equal') used

[Jonathan S. <js...@cf...>]

Hi all,

I've run across a minor but annoying bug.  It can be demonstrated pretty
simply:

fig, ax = plt.subplots(2,1,sharex=True,figsize=(7.,7.))
fig.subplots_adjust(hspace=0.0)
x = 4.25*(np.arange(6.) - 2.5)/10.
y =  0.6*x/max(x)
ax[0].plot(x,y)
ax[0].set_xlim(-1.2,1.2)
ax[0].set_aspect('equal')
ax[1].plot(x,y)
ax[0].set_ylim(-0.6,0.6)
ax[1].set_ylim(-0.6,0.6)
ax[1].set_aspect('equal')
plt.show()

The problem is that the y limits on the two plots are slightly different
from those set:
ax[1].get_ylim()
(-0.61935483870967734, 0.61935483870967734)
and doing a set_ylim doesn't have any effect.  This seems to be caused
by the set_aspect('equal'), since removing it results in plots with the
correct limits -- but aspect that is not quite equal.  It is affected by
the figsize parameter in the call to subplots.  It seems I can get the
correct y limits and aspect if I keep the set_aspect('equal') and fiddle
with the figsize.  But that certainly doesn't seem to be a desirable
behavior.  Ideally, the set_ylim (or set_xlim) would be respected as
well as the apect ratio and extra blank space around the figure would be
added as needed to fit the figsize.

By the way, using no figsize argument to subplots results in y limits
even smaller than the data limits.  Also, this problem does not occur
for single (non-stacked) plots and the use of subplots_adjust also does
not seem to affect the problem.  I'm using matplotlib 1.2.0

I did notice that this issue is similar to that discussed in this
thread:
http://www.mail-archive.com/mat...@li.../msg05783.html

Regards,
Jon
-- 
______________________________________________________________
Jonathan D. Slavin              Harvard-Smithsonian CfA
js...@cf...         60 Garden Street, MS 83
phone: (617) 496-7981           Cambridge, MA 02138-1516
 cell: (781) 363-0035           USA
______________________________________________________________