title                package:graphics                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 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.lab")' and color 'par("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'. 
          '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 a 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'.

References:

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

See Also:

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

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, 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),
          labels = expression(-pi, -pi/2, 0, pi/2, pi))
     abline(h = 0, v = pi/2 * c(-1,1), lty = 2, lwd = .1, col = "gray70")

