| 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$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 |
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 |
adj |
one or two values in [0, 1] which specify the x (and optionally y) adjustment (‘justification’) of the labels, with 0 for left/bottom, 1 for right/top, and 0.5 for centered. On most devices values outside [0, 1] will also work. See below. |
pos |
a position specifier for the text. If specified this
overrides any |
offset |
when |
vfont |
|
cex |
numeric character expansion factor; multiplied
by |
col, font |
the color and (if |
... |
further graphical parameters (from |
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 position with respect to
(x, y).
Values of 0, 0.5, and 1 specify that (x, y) should align with
the left/bottom, middle and
right/top of the text, 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). When adj is specified, a non-zero
srt rotates the label about (x, y). If pos is
specified, srt rotates the text about the point on its bounding
box which is closest to (x, y): top center for pos = 1,
right center for pos = 2, bottom center for pos = 3, and
left center for pos = 4. The pos interface is not as
useful for rotated text because the result is no longer centered
vertically or horizontally with respect to (x, y). At present
there is no interface in the graphics package for directly
rotating text about its center which is achievable however by fiddling
with adj and srt simultaneously.
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.
The Euro symbol may not be available in older fonts. In current
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 (and the font will need to contain the Euro
glyph, which for example older printers may not).
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.
text.formula for the formula method;
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)")