R: Write Text into the Margins of a Plot

mtext {graphics}

R Documentation

Write Text into the Margins of a Plot

Description

Text is written in one of the four margins of the current figure region or one of the outer margins of the device region.

Usage

mtext(text, side = 3, line = 0, outer = FALSE, at = NA,
      adj = NA, padj = NA, cex = NA, col = NA, font = NA, vfont = NULL, ...)

Arguments

text

one or more character strings or expressions.

side

on which side of the plot (1=bottom, 2=left, 3=top, 4=right).

line

on which MARgin line, starting at 0 counting outwards.

outer

use outer margins if available.

at

give location in user-coordinates. If length(at)==0 (the default), the location will be determined by adj.

adj

adjustment for each string in reading direction. For strings parallel to the axes, adj=0 means left or bottom alignment, and adj=1 means right or top alignment. If adj is not a finite value (the default), the value of par("las") determines the adjustment. For strings plotted parallel to the axis the default is to centre the string.

padj

adjustment for each string perpendicular to the reading direction (which is controlled by adj). For strings parallel to the axes, padj=0 means right or top alignment, and padj=1 means left or bottom alignment.

If padj is not a finite value (the default), the value of par("las") determines the adjustment. For strings plotted perpendicular to the axis the default is to centre the string.

...

Further graphical parameters (see text and par) ; currently supported are:

cex

character expansion factor (default = 1).

col

color to use.

font

font for text.

vfont

vector font for text.

Details

The “user coordinates” in the outer margins always range from zero to one, and are not affected by the user coordinates in the figure region(s) — R is differing here from other implementations of S.

The arguments side, line, at, at, adj, the further graphical parameters and even outer can be vectors, and recycling will take place to plot as many strings as the longest of the vector arguments. Note that a vector adj has a different meaning from text.

adj = 0.5 will centre the string, but for outer=TRUE on the device region rather than the plot region.

Parameter las will determine the orientation of the string(s). For strings plotted perpendicular to the axis the default justification is to place the end of the string nearest the axis on the specified line. (Note that this differs from S, which uses srt if at is supplied and las if it is not.)

Note that if the text is to be plotted perpendicular to the axis, adj determines the justification of the string and the position along the axis unless at is specified.

Side Effects

The given text is written onto the current plot.

References

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

Examples

plot(1:10, (-4:5)^2, main="Parabola Points", xlab="xlab")
mtext("10 of them")
for(s in 1:4)
    mtext(paste("mtext(..., line= -1, {side, col, font} = ",s,
          ", cex = ", (1+s)/2, ")"), line = -1,
          side=s, col=s, font=s, cex= (1+s)/2)
mtext("mtext(..., line= -2)", line = -2)
mtext("mtext(..., line= -2, adj = 0)", line = -2, adj =0)
##--- log axis :
plot(1:10, exp(1:10), log='y', main="log='y'", xlab="xlab")
for(s in 1:4) mtext(paste("mtext(...,side=",s,")"), side=s)

[Package graphics version 2.0.0 ]