matplotlib/matplotlib — pull request #1022 by efiring (2012-07-17 19:28:42+00:00)
Title: contour: map extended ranges to "under" and "over" values

Contourf was handling the extend kwarg by mapping the extended
ranges directly into the 0-1 normal colormap range, so that
using set_under and set_over had no effect; after this change, the
extended ranges are mapped outside the 0-1 range (after applying
the norm) so that the colors established by the set_under and set_over
colormap methods are used. By default, these are the end values of
the colormap. The new behavior matches the existing contourf documentation.

Fixed a bug in which the legend support for extend options was using the
wrong names for the options.