or decreases the color intensities in a colormap by replacing the
current colormap with a brighter or darker colormap of essentially
the same colors. The modified colormap is brighter if 0 <
beta < 1 and darker if -1 < beta < 0. brighten(beta),
followed by brighten(-beta), where beta
< 1, restores the original map.
all objects that are children of the figure having the handle h.
newmap = brighten(beta) returns
a brighter or darker version of the current colormap without changing
newmap = brighten(cmap,beta) returns
a brighter or darker version of the colormap cmap without
changing the display.