matplotlib/matplotlib — pull request #941 by kaufman (2012-06-10 14:45:46+00:00)
Title: 	update axes.arrow() and patches.FancyArrow documentation

old help:

arrow(x, y, dx, dy, hold=None, **kwargs)
Call signature::

arrow(x, y, dx, dy, **kwargs)

Draws arrow on specified axis from (*x*, *y*) to (*x* + *dx*,
*y* + *dy*).

Optional kwargs control the arrow properties:

Constructor arguments

*length_includes_head*:
*True* if head is counted in calculating the length.

*shape*: ['full', 'left', 'right']

*overhang*:
distance that the arrow is swept back (0 overhang means
triangular shape).

*head_starts_at_zero*:
If *True*, the head starts being drawn at coordinate 0
instead of ending at coordinate 0.

Valid kwargs are:
agg_filter: unknown
alpha: float or None
...
===============================

new help:

arrow(x, y, dx, dy, hold=None, **kwargs)
Call signature::

arrow(x, y, dx, dy, **kwargs)

Draws arrow on specified axis from (*x*, *y*) to (*x* + *dx*,
*y* + *dy*). Uses FancyArrow patch to construct the arrow.

Optional kwargs control the arrow construction and properties:

Constructor arguments
width: float (default: 0.001)
width of full arrow tail

length_includes_head: [True | False] (default: False)
True if head is to be counted in calculating the length.

head_width: float or None (default: 3*width)
total width of the full arrow head

head_length: float or None (default: 1.5 * head_width)
length of arrow head

shape: ['full', 'left', 'right'] (default: 'full')
draw the left-half, right-half, or full arrow

overhang: float (default: 0)
fraction that the arrow is swept back (0 overhang means
triangular shape). Can be negative or greater than one.

head_starts_at_zero: [True | False] (default: False)
if True, the head starts being drawn at coordinate 0
instead of ending at coordinate 0.

Other valid kwargs (inherited from Patch) are:
agg_filter: unknown
alpha: float or None
...