| % File src/library/graphics/man/zAxis.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2010 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{Axis} |
| \alias{Axis} |
| \title{Generic Function to Add an Axis to a Plot} |
| \description{ |
| Generic function to add a suitable axis to the current plot. |
| } |
| \usage{ |
| Axis(x = NULL, at = NULL, \dots, side, labels = NULL) |
| } |
| \arguments{ |
| \item{x}{an object which indicates the range over which an axis should |
| be drawn} |
| \item{at}{the points at which tick-marks are to be drawn.} |
| \item{side}{an integer specifying which side of the plot the axis is |
| to be drawn on. The axis is placed as follows: 1=below, |
| 2=left, 3=above and 4=right.} |
| \item{labels}{this can either be a logical value specifying whether |
| (numerical) annotations are to be made at the tickmarks, or a |
| character or expression vector of labels to be placed at the |
| tickpoints. If this is specified as a character or expression |
| vector, \code{at} should be supplied and they should be the same |
| length.} |
| \item{\dots}{arguments to be passed to methods and perhaps then to |
| \code{\link{axis}}.} |
| } |
| \value{ |
| The numeric locations on the axis scale at which tick marks were drawn |
| when the plot was first drawn (see \sQuote{Details}). |
| |
| This function is usually invoked for its side effect, which is to add |
| an axis to an already existing plot. |
| } |
| \details{ |
| This is a generic function. It works in a slightly non-standard way: |
| if \code{x} is supplied and non-NULL it dispatches on \code{x}, |
| otherwise if \code{at} is supplied and non-NULL it dispatches on \code{at}, |
| and the default action is to call \code{\link{axis}}, omitting argument |
| \code{x}. |
| |
| The idea is that for plots for which either or both of the axes are |
| numerical but with a special interpretation, the standard plotting |
| functions (including \code{\link{boxplot}}, \code{\link{contour}}, |
| \code{\link{coplot}}, \code{\link{filled.contour}}, |
| \code{\link{pairs}}, \code{\link{plot.default}}, \code{\link{rug}} and |
| \code{\link{stripchart}}) will set up user coordinates and \code{Axis} |
| will be called to label them appropriately. |
| |
| There are \code{"Date"} and \code{"POSIXt"} methods which can pass an |
| argument \code{format} on to the appropriate \code{axis} method (see |
| \code{\link{axis.POSIXct}}). |
| } |
| \seealso{ |
| \code{\link{axis}} (which is eventually called from all \code{Axis()} |
| methods in package \pkg{graphics}. |
| } |
| \keyword{aplot} |