# Changes for 0.81¶

- pylab and artist "set" functions renamed to setp to avoid clash
with python2.4 built-in set.  Current version will issue a
deprecation warning which will be removed in future versions

- imshow interpolation arguments changes for advanced interpolation
schemes.  See help imshow, particularly the interpolation,

- Support for masked arrays has been added to the plot command and
to the Line2D object.  Only the valid points are plotted.  A
"valid_only" kwarg was added to the get_xdata() and get_ydata()
methods of Line2D; by default it is False, so that the original
data arrays are returned. Setting it to True returns the plottable
points.

- contour changes:

the variable to be contoured.  Masking works correctly for
contour, but a bug remains to be fixed before it will work for
functions.

Level argument changes:

Old version: a list of levels as one of the positional
arguments specified the lower bound of each filled region; the
upper bound of the last region was taken as a very large
number.  Hence, it was not possible to specify that z values
between 0 and 1, for example, be filled, and that values
outside that range remain unfilled.

New version: a list of N levels is taken as specifying the
boundaries of N-1 z ranges.  Now the user has more control over
what is colored and what is not.  Repeated calls to contourf
(with different colormaps or color specifications, for example)
can be used to color different ranges of z.  Values of z
outside an expected range are left uncolored.

Example:
Old: contourf(z, [0, 1, 2]) would yield 3 regions: 0-1, 1-2, and >2.
New: it would yield 2 regions: 0-1, 1-2.  If the same 3 regions were
desired, the equivalent list of levels would be [0, 1, 2,
1e38].