text {graphics}R Documentation

Add Text to a Plot

Description

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.

Usage

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, xpd = NULL, ...)

Arguments

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 one or more character strings or expressions specifying the text to be written. An attempt is made to coerce other vectors (and factors) to character, and other language objects to expressions. 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 if a character vector of length 2 is specified, then Hershey vector fonts are used. The first element of the vector selects a typeface and the second element selects a style.
cex numeric character expansion factor; multiplied by par("cex") yields the final character size.
col, font the color and font to be used; these default to the values of the global graphical parameters in par().
xpd (where) should clipping take place? Defaults to par("xpd").
... further graphical parameters (from par).

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, 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.

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).

Labels whose x, y, labels, cex or col value is NA are omitted from the plot.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

mtext, title, Hershey for details on Hershey vector fonts, plotmath for details and more examples on mathematical annotation.

Examples

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 ę, but not « ...")
mtext("źISO-accents╗: ▒ ÚŔ °ě ň<┼ Š<Ă", 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 franšais, c'est fašile: RŔgles, LibertÚ, EgalitÚ, FraternitÚ...")
text(5,9.8, "Jetz no chli zŘritŘŘtsch: (noch ein bi▀chen ZŘrcher deutsch)")

[Package graphics version 2.1.0 Index]