Plot Annotation
Description
This function can be used to add labels to a plot. Its first four
principal arguments can also be used as arguments in most high-level
plotting functions. They must be of type character or
expression . In the latter case, quite a bit of
mathematical notation is available such as sub- and superscripts,
Greek letters, fractions, etc: see plotmath
Usage
title(main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
line = NA, outer = FALSE, ...)
Arguments
main
The main title (on top) using font, size (character
expansion) and color par(c("font.main", "cex.main", "col.main")).
sub
Sub-title (at bottom) using font, size and color
par(c("font.sub", "cex.sub", "col.sub")).
xlab
X axis label using font, size and color
par(c("font.lab", "cex.lab", "col.lab")).
ylab
Y axis label, same font attributes as xlab.
line
specifying a value for line overrides the
default placement of labels, and places them this many lines
outwards from the plot edge.
outer
a logical value. If TRUE, the titles are
placed in the outer margins of the plot.
...
further graphical parameters from par . Use
e.g., col.main or cex.sub instead of just col
or cex. adj controls the justification of the titles.
xpd can be used to set the clipping region:
this defaults to the figure region unless outer = TRUE,
otherwise the device region and can only be increased. mgp
controls the default placing of the axis titles.
Details
The labels passed to title can be character strings or
language objects (names, calls or expressions), or a list
containing the string to be plotted, and a selection of the optional
modifying graphical parameters cex=, col= and
font=. Other objects will be coerced by
as.graphicsAnnot .
The position of main defaults to being vertically centered in
(outer) margin 3 and justified horizontally according to
par("adj") on the plot region (device region for
outer = TRUE).
The positions of xlab, ylab and sub are
line (default for xlab and ylab being
par("mgp")[1] and increased by 1 for sub) lines
(of height par("mex")) into the appropriate margin, justified
in the text direction according to par("adj") on the
plot/device region.
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
See Also
mtext , text ;
plotmath for details on mathematical annotation.
Examples
plot(cars, main = "") # here, could use main directly
title(main = "Stopping Distance versus Speed")
plot(cars, main = "")
title(main = list("Stopping Distance versus Speed", cex = 1.5,
col = "red", font = 3))
## Specifying "..." :
plot(1, col.axis = "sky blue", col.lab = "thistle")
title("Main Title", sub = "subtitle",
cex.main = 2, font.main= 4, col.main= "blue",
cex.sub = 0.75, font.sub = 3, col.sub = "red")
x <- seq(-4, 4, length.out = 101)
y <- cbind(sin(x), cos(x))
matplot(x, y, type = "l", xaxt = "n",
main = expression(paste(plain(sin) * phi, " and ",
plain(cos) * phi)),
ylab = expression("sin" * phi, "cos" * phi), # only 1st is taken
xlab = expression(paste("Phase Angle ", phi)),
col.main = "blue")
axis(1, at = c(-pi, -pi/2, 0, pi/2, pi),
labels = expression(-pi, -pi/2, 0, pi/2, pi))
abline(h = 0, v = pi/2 * c(-1,1), lty = 2, lwd = .1, col = "gray70")