text
Add Text to a Plot
text draws the strings given in the vector labels at the
coordinates given by x and y.
y may be missing since xy.coords(x, y) is used for
construction of the coordinates.
- Keywords
- aplot
Usage
text(x, ...)
"text" (x, y = NULL, labels = seq_along(x), adj = NULL, pos = NULL, offset = 0.5, vfont = NULL, cex = 1, col = NULL, font = NULL, ...)Arguments
- x, y
- numeric vectors of coordinates where the text
labelsshould be written. If the length ofxandydiffers, the shorter one is recycled. - labels
- a character vector or expression specifying
the text to be written. An attempt is made to coerce other
language objects (names and calls) to expressions, and vectors and
other classed objects to character vectors by
as.character. Iflabelsis longer thanxandy, the coordinates are recycled to the length oflabels. - adj
- one or two values in $[0, 1]$ which specify the x (and optionally y) adjustment of the labels. On most devices values outside that interval will also work.
- pos
- a position specifier for the text. If specified this
overrides any
adjvalue given. Values of1,2,3and4, respectively indicate positions below, to the left of, above and to the right of the specified coordinates. - offset
- when
posis specified, this value gives the offset of the label from the specified coordinate in fractions of a character width. - vfont
NULLfor the current font family, or a character vector of length 2 for Hershey vector fonts. The first element of the vector selects a typeface and the second element selects a style. Ignored iflabelsis an expression.- cex
- numeric character expansion factor; multiplied
by
par("cex")yields the final character size.NULLandNAare equivalent to1.0. - col, font
- the color and (if
vfont = NULL) font to be used, possibly vectors. These default to the values of the global graphical parameters inpar(). - ...
- further graphical parameters (from
par), such assrt,familyandxpd.
Details
labels must be of type character or
expression (or be coercible to such a type).
In the latter case, quite a bit of
mathematical notation is available such as sub- and superscripts,
greek letters, fractions, etc.
adj allows adjustment of the text with respect to
(x, y).
Values of 0, 0.5, and 1 specify left/bottom, middle and
right/top alignment, respectively. The default is for centered text, i.e.,
adj = c(0.5, NA). Accurate vertical centering needs
character metric information on individual characters which is
only available on some devices. Vertical alignment is done slightly
differently for character strings and for expressions:
adj = c(0,0) means to left-justify and to align on the baseline
for strings but on the bottom of the bounding box for expressions.
This also affects vertical centering: for strings the centering
excludes any descenders whereas for expressions it includes them.
Using NA for strings centers them, including descenders.
The pos and offset arguments can be used in conjunction
with values returned by identify to recreate an interactively
labelled plot.
Text can be rotated by using graphical parameters srt
(see par); this rotates about the centre set by
adj.
Graphical parameters col, cex and font can be
vectors and will then be applied cyclically to the labels (and
extra values will be ignored). NA values of font are
replaced by par("font"), and similarly for col.
Labels whose x, y or labels value is NA
are omitted from the plot.
What happens when font = 5 (the symbol font) is selected can be
both device- and locale-dependent. Most often labels will be
interpreted in the Adobe symbol encoding, so e.g. "d" is delta,
and "\300" is aleph.
Euro symbol
The Euro symbol was introduced relatively recently and may not be
available in older fonts. In recent versions of Adobe symbol fonts it
is character 160, so text(x, y, "\xA0", font = 5) may work.
People using Western European locales on Unix-alikes can probably
select ISO-8895-15 (Latin-9) which has the Euro as character 165: this
can also be used for postscript and pdf.
It is \u20ac in Unicode, which can be used in UTF-8 locales.
unix The Euro should be rendered correctly by X11 in UTF-8
locales, but the corresponding single-byte encoding in
postscript and pdf will need to be selected
as ISOLatin9.enc.
windows In all the European Windows encodings the Euro is symbol 128 and
\u20ac will work in all locales: however not all fonts will
include it. It is not in the symbol font used for
windows and related devices, including the Windows printer.
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
Murrell, P. (2005) R Graphics. Chapman & Hall/CRC Press.
See Also
text.formula for the formula method;
mtext, title,
Hershey for details on Hershey vector fonts,
plotmath for details and more examples on
mathematical annotation.
Examples
library(graphics)
plot(-1:1, -1:1, type = "n", xlab = "Re", ylab = "Im")
K <- 16; text(exp(1i * 2 * pi * (1:K) / K), col = 2)
## The following two examples use latin1 characters: these may not
## appear correctly (or be omitted entirely).
plot(1:10, 1:10, main = "text(...) examples\n~~~~~~~~~~~~~~",
sub = "R is GNU ©, but not ® ...")
mtext("«Latin-1 accented chars»: éè øØ å<Å æ<Æ", side = 3)
points(c(6,2), c(2,1), pch = 3, cex = 4, col = "red")
text(6, 2, "the text is CENTERED around (x,y) = (6,2) by default",
cex = .8)
text(2, 1, "or Left/Bottom - JUSTIFIED at (2,1) by 'adj = c(0,0)'",
adj = c(0,0))
text(4, 9, expression(hat(beta) == (X^t * X)^{-1} * X^t * y))
text(4, 8.4, "expression(hat(beta) == (X^t * X)^{-1} * X^t * y)",
cex = .75)
text(4, 7, expression(bar(x) == sum(frac(x[i], n), i==1, n)))
## Two more latin1 examples
text(5, 10.2,
"Le français, c'est façile: Règles, Liberté, Egalité, Fraternité...")
text(5, 9.8,
"Jetz no chli züritüütsch: (noch ein bißchen Zürcher deutsch)")