I encountered a strange error when trying to put some annotations on 
a graph.  I was able to simplify it to this:

pyplot.plot([1, 2, 3, 4], [0, -1, -2, 8])
pyplot.annotate("Blah", xy=(2, 2), xytext=(-20,-20), 
textcoords='offset points',
                 bbox=dict(boxstyle='round,pad=0.5'),
                 arrowprops=dict(arrowstyle='fancy', 
connectionstyle='arc3,rad=0'))

On my system (matplotlib 1.1.0 with Python 2.6 on Windows XP), this 
causes a long traceback culminating in

File "C:\Program Files\Python\lib\site-packages\matplotlib\bezier.py", 
line 129, in find_bezier_t_intersecting_with_closedpath
     raise ValueError("the segment does not seemed to intersect with 
the path")

        Increasing the xytext coordinates (in absolute value), to for 
instance (-50, -50) works with no error, and it also works without the 
special bbox style.  Just guessing from the error message, it looks 
like certain combinations of fancy patches are causing problems 
because the shapes don't intersect in the way the drawing code assumes 
they should.

        I don't see anything in the docs about such edge cases, so this looks 
like a bug.  Judging from the way that small tweaks to the code can 
cause the error to disappear, I imagine it could be tricky to fix, but 
at the least there should probably be a warning in the docs that some 
kinds of anootation boxes won't work with some kinds of arrows when 
the text is too close to the annotated point.

        Any ideas?

Thanks.
-- 
Brendan Barnwell
"Do not follow where the path may lead.  Go, instead, where there is 
no path, and leave a trail."
    --author unknown

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