Hi,
I wonder if there is a missing trigger for autoscale when using patches?
The minimal example shows up as a quarter circle with axis bounds 0,1.
I noticed this when using bigger patches and the canvas appeared completely empty.
After some moments of wondering why the patch was not there I noticed the axis bounds.
A call to ax.autoscale() puts the full circle in view.

mpl 1.5.3

If you consider this to be a feature I'm fine with closing the issue.
If you consider that it should be fixed and you think it's an easy fix, please give me some hints of where to make the trigger(s), If so I will make an attempt to fix it. If you think it belongs to the larger autoscale discussion that seems to be ongoing at the moment, maybe it could be considered there.

minimal example:

import matplotlib.pyplot as plt
from matplotlib.patches import Wedge
fig, ax = plt.subplots()
w = Wedge((0, 0), 1, 0, 360, width=0.2)
ax.set_aspect('equal')
ax.add_patch(w)
plt.show()