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title: Plot Annotation

title

R Documentation

Plot Annotation

Description

This function can be used to add labels to a plot. Its first four principal arguments can also be used as arguments in most high-level plotting functions. They must be of type character or expression. In the latter case, quite a bit of mathematical notation is available such as sub- and superscripts, greek letters, fractions, etc: see plotmath

Usage

title(main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
      line = NA, outer = FALSE, ...)

Arguments

`main`	The main title (on top) using font, size (character expansion) and color `par(c("font.main", "cex.main", "col.main"))`.
`sub`	Sub-title (at bottom) using font, size and color `par(c("font.sub", "cex.sub", "col.sub"))`.
`xlab`	X axis label using font, size and color `par(c("font.lab", "cex.lab", "col.lab"))`.
`ylab`	Y axis label, same font attributes as `xlab`.
`line`	specifying a value for `line` overrides the default placement of labels, and places them this many lines outwards from the plot edge.
`outer`	a logical value. If `TRUE`, the titles are placed in the outer margins of the plot.
`...`	further graphical parameters from `par`. Use e.g., `col.main` or `cex.sub` instead of just `col` or `cex`. `adj` controls the justification of the titles. `xpd` can be used to set the clipping region: this defaults to the figure region unless `outer = TRUE`, otherwise the device region and can only be increased. `mgp` controls the default placing of the axis titles.

Details

The labels passed to title can be character strings or language objects (names, calls or expressions), or a list containing the string to be plotted, and a selection of the optional modifying graphical parameters cex=, col= and font=. Other objects will be coerced by as.graphicsAnnot.

The position of main defaults to being vertically centered in (outer) margin 3 and justified horizontally according to par("adj") on the plot region (device region for outer = TRUE).

The positions of xlab, ylab and sub are line (default for xlab and ylab being par("mgp")[1] and increased by 1 for sub) lines (of height par("mex")) into the appropriate margin, justified in the text direction according to par("adj") on the plot/device region.

References

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

Examples

plot(cars, main = "") # here, could use main directly
title(main = "Stopping Distance versus Speed")

plot(cars, main = "")
title(main = list("Stopping Distance versus Speed", cex = 1.5,
                  col = "red", font = 3))

## Specifying "..." :
plot(1, col.axis = "sky blue", col.lab = "thistle")
title("Main Title", sub = "sub title",
      cex.main = 2,   font.main= 4, col.main= "blue",
      cex.sub = 0.75, font.sub = 3, col.sub = "red")


x <- seq(-4, 4, length.out = 101)
y <- cbind(sin(x), cos(x))
matplot(x, y, type = "l", xaxt = "n",
        main = expression(paste(plain(sin) * phi, "  and  ",
                                plain(cos) * phi)),
        ylab = expression("sin" * phi, "cos" * phi), # only 1st is taken
        xlab = expression(paste("Phase Angle ", phi)),
        col.main = "blue")
axis(1, at = c(-pi, -pi/2, 0, pi/2, pi),
     labels = expression(-pi, -pi/2, 0, pi/2, pi))
abline(h = 0, v = pi/2 * c(-1,1), lty = 2, lwd = .1, col = "gray70")