The pllegend and plcolorbar routines are available in PLplot to
provide users with the capability of visually annotating their plots
with a legend (a series of patterned boxes, lines, or symbols with
associated explanatory UTF-8 text) or a color bar (an annotated
subplot representing a continuous range of colors within the main
plot and typically identifying certain colors with certain numerical
values using an axis). pllegend is useful for visually annotating
most two-dimensional plots. See our standard examples 04 and26 for some
examples. plcolorbar is especially useful for annotating continuous
shade plots generated by plshades. See our standard example 16, for an
example.
The pllegend and plcolorbar routines provide the users
complete and convenient control of the size and position of the
results on the plot and also return size data that makes it
straightforward to stack different legend or colorbar results together
on the plot (see our standard example
33 for an example of this capability). Furthermore, the
pllegend and plcolorbar routines provide the user with many
different style possibilities for the results. Because of all these
features, pllegend and plcolorbar have an extensive argument list.
So we recommend first-time users of pllegend and plcolorbar use
our standard examples 04, 16, and 26 as a tutorial
on how to use these PLplot capabilities in a simple way, and for more
advanced use we recommend studying the pllegend and plcolorbar
documentation and also our standard example
33 which attempts to exercise most capabilities of these two
PLplot functions.