title                  package:base                  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.

Usage:

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

Arguments:

    main: The main title (on top) using font and size (character
          expansion) `par("font.main")' and color `par("col.main")'.

     sub: Sub-title (at bottom) using font and size `par("font.sub")'
          and color `par("col.sub")'.

    xlab: X axis label using font and character expansion
          `par("font.axis")' and color `par("col.axis")'.

    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 from the plot.

   outer: a logical value.  If `TRUE', the titles are placed in the
          outer margins of the plot.

     ...: further graphical parameters (from `par').

Details:

     The labels passed to title can be simple strings or expressions,
     or they can be a list containing the string to be plotted, and a
     selection of the optional modifying graphical parameters `cex=',
     `col=', `font='.

See Also:

     `mtext', `text'; `plotmath' for details on mathematical
     annotation.

Examples:

     data(cars)
     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))

     x <- seq(-4, 4, len = 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),
          lab = expression(-pi, -pi/2, 0, pi/2, pi))
     abline(h = 0, v = pi/2 * c(-1,1), lty = 2, lwd = .1, col = "gray70")

