text {graphics} | R Documentation |
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.
text(x, ...) ## Default S3 method: text (x, y = NULL, labels = seq_along(x), adj = NULL, pos = NULL, offset = 0.5, vfont = NULL, cex = 1, col = NULL, font = NULL, ...)
x, y |
numeric vectors of coordinates where the text
labels should be written. If the length of x and
y differs, 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 .
If labels is longer than x and
y , the coordinates are recycled to the length of labels . |
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 adj value given. Values of 1 ,
2 , 3 and 4 , respectively indicate
positions below, to the left of, above and to the right of
the specified coordinates. |
offset |
when pos is specified, this value gives the
offset of the label from the specified coordinate in fractions
of a character width. |
vfont |
NULL for 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 if labels is an expression. |
cex |
numeric character expansion factor; multiplied
by par("cex") yields the final character size.
NULL and NA are equivalent to 1.0 . |
col, font |
the color and (if vfont = NULL ) font to be
used, possibly vectors. These default to the values of the global
graphical parameters in par() . |
... |
further graphical parameters (from par ),
such as srt , family and xpd . |
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, 0.5)
. 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.
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")
.
Labels whose x
, y
, labels
, cex
or col
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.
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.
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
.
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.
mtext
, title
,
Hershey
for details on Hershey vector fonts,
plotmath
for details and more examples on
mathematical annotation.
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)")