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", box.col = NULL,
box.lwd = 1, box.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.
border.lty,border.lwd
the line type and width for
the legend border.
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.