Usage
legend(x, y = NULL, legend, fill = NULL, col = par("col"), lty, lwd, pch, angle = 45, density = NULL, bty = "o", bg = par("bg"), pt.bg = NA, cex = 1, pt.cex = cex, pt.lwd = lwd, xjust = 0, yjust = 1, x.intersp = 1, y.intersp = 1, adj = c(0, 0.5), text.width = NULL, text.col = par("col"), merge = do.lines && has.pch, trace = FALSE, plot = TRUE, ncol = 1, horiz = FALSE, title = NULL, inset = 0, border.col = NULL, border.lwd = 1, border.lty = "solid")Arguments
x, y
the x and y co-ordinates to be used to position the legend.
They can be specified by keyword or in any way which is accepted by
xy.coords: See Details. legend
a character or expression vector.
of length $\ge 1$ to appear in the legend. fill
if specified, this argument will cause boxes filled
with the specified colors (or shaded in the specified colors)
to appear beside the legend text.
col
the color of points or lines appearing in the legend.
lty, lwd
the line types and widths for lines appearing in the
legend. One of these two must be specified for line drawing.
pch
the plotting symbols appearing in the legend, either as
vector of 1-character strings, or one (multi character)
string. Must be specified for symbol drawing.
angle
angle of shading lines.
density
the density of shading lines, if numeric and
positive. If NULL or negative or NA color filling
is assumed.
bty
the type of box to be drawn around the legend. The allowed
values are "o" (the default) and "n".
bg
the background color for the legend box. (Note that this is
only used if bty != "n".)
box.lty, box.lwd
the line type and width for the legend box.
pt.bg
the background color for the points,
corresponding to its argument bg. cex
character expansion factor relative to current
par("cex").
pt.cex
expansion factor(s) for the points.
pt.lwd
line width for the points, defaults to the one for
lines, or if that is not set, to par("lwd").
xjust
how the legend is to be justified relative to the legend
x location. A value of 0 means left justified, 0.5 means centered
and 1 means right justified.
yjust
the same as xjust for the legend y location.
x.intersp
character interspacing factor for horizontal (x) spacing.
y.intersp
the same for vertical (y) line distances.
adj
numeric of length 1 or 2; the string adjustment for legend
text. Useful for y-adjustment when labels are
plotmath expressions. text.width
the width of the legend text in x ("user")
coordinates. (Should be positive even for a reversed x axis.)
Defaults to the proper value computed by strwidth(legend). text.col
the color used for the legend text.
merge
logical; if TRUE, merge points and lines but
not filled boxes. Defaults to TRUE if there are points and lines.
trace
logical; if TRUE, shows how legend does all
its magical computations.
plot
logical. If FALSE, nothing is plotted but the
sizes are returned.
ncol
the number of columns in which to set the legend items
(default is 1, a vertical legend).
horiz
logical; if TRUE, set the legend horizontally
rather than vertically (specifying horiz overrides the ncol
specification).
title
a character string or length-one expression giving a
title to be placed at the top of the legend.
inset
inset distance(s) from the margins as a fraction of the
plot region when legend is placed by keyword.