R: Draw an X-Axis

grid.xaxis {grid}

R Documentation

Draw an X-Axis

Description

These functions create and draw an x-axis.

Usage

grid.xaxis(at = NULL, label = TRUE, main = TRUE,
           edits = NULL, name = NULL,
           gp = gpar(), draw = TRUE, vp = NULL)

xaxisGrob(at = NULL, label = TRUE, main = TRUE,
          edits = NULL, name = NULL,
          gp = gpar(), vp = NULL)

Arguments

`at`	A numeric vector of x-value locations for the tick marks.
`label`	A logical value indicating whether to draw the labels on the tick marks, or an expression or character vector which specify the labels to use. If not logical, must be the same length as the `at` argument.
`main`	A logical value indicating whether to draw the axis at the bottom (`TRUE`) or at the top (`FALSE`) of the viewport.
`edits`	A gEdit or gEditList containing edit operations to apply (to the children of the axis) when the axis is first created and during redrawing whenever `at` is `NULL`.
`name`	A character identifier.
`gp`	An object of class `"gpar"`, typically the output from a call to the function `gpar`. This is basically a list of graphical parameter settings.
`draw`	A logical value indicating whether graphics output should be produced.
`vp`	A Grid viewport object (or `NULL`).

Details

Both functions create an xaxis grob (a graphical object describing an xaxis), but only grid.xaxis draws the xaxis (and then only if draw is TRUE).

Value

An xaxis grob. grid.xaxis returns the value invisibly.

Children

If the at slot of an xaxis grob is not NULL then the xaxis will have the following children:

major: representing the line at the base of the tick marks.
ticks: representing the tick marks.
labels: representing the tick labels.

If the at slot is NULL then there are no children and ticks are drawn based on the current viewport scale.

Author(s)

Paul Murrell