discrete_scale.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/scale-.r
\name{discrete_scale}
\alias{discrete_scale}
\title{Discrete scale constructor}
\usage{
discrete_scale(
  aesthetics,
  scale_name,
  palette,
  name = waiver(),
  breaks = waiver(),
  labels = waiver(),
  limits = NULL,
  expand = waiver(),
  na.translate = TRUE,
  na.value = NA,
  drop = TRUE,
  guide = "legend",
  position = "left",
  super = ScaleDiscrete
)
}
\arguments{
\item{aesthetics}{The names of the aesthetics that this scale works with.}

\item{scale_name}{The name of the scale that should be used for error messages
associated with this scale.}

\item{palette}{A palette function that when called with a single integer
argument (the number of levels in the scale) returns the values that
they should take (e.g., \code{\link[scales:hue_pal]{scales::hue_pal()}}).}

\item{name}{The name of the scale. Used as the axis or legend title. If
\code{waiver()}, the default, the name of the scale is taken from the first
mapping used for that aesthetic. If \code{NULL}, the legend title will be
omitted.}

\item{breaks}{One of:
\itemize{
\item \code{NULL} for no breaks
\item \code{waiver()} for the default breaks (the scale limits)
\item A character vector of breaks
\item A function that takes the limits as input and returns breaks
as output. Also accepts rlang \link[rlang:as_function]{lambda} function
notation.
}}

\item{labels}{One of:
\itemize{
\item \code{NULL} for no labels
\item \code{waiver()} for the default labels computed by the
transformation object
\item A character vector giving labels (must be same length as \code{breaks})
\item An expression vector (must be the same length as breaks). See ?plotmath for details.
\item A function that takes the breaks as input and returns labels
as output. Also accepts rlang \link[rlang:as_function]{lambda} function
notation.
}}

\item{limits}{One of:
\itemize{
\item \code{NULL} to use the default scale values
\item A character vector that defines possible values of the scale and their
order
\item A function that accepts the existing (automatic) values and returns
new ones. Also accepts rlang \link[rlang:as_function]{lambda} function
notation.
}}

\item{expand}{For position scales, a vector of range expansion constants used to add some
padding around the data to ensure that they are placed some distance
away from the axes. Use the convenience function \code{\link[=expansion]{expansion()}}
to generate the values for the \code{expand} argument. The defaults are to
expand the scale by 5\% on each side for continuous variables, and by
0.6 units on each side for discrete variables.}

\item{na.translate}{Unlike continuous scales, discrete scales can easily show
missing values, and do so by default. If you want to remove missing values
from a discrete scale, specify \code{na.translate = FALSE}.}

\item{na.value}{If \code{na.translate = TRUE}, what aesthetic value should the
missing values be displayed as? Does not apply to position scales
where \code{NA} is always placed at the far right.}

\item{drop}{Should unused factor levels be omitted from the scale?
The default, \code{TRUE}, uses the levels that appear in the data;
\code{FALSE} uses all the levels in the factor.}

\item{guide}{A function used to create a guide or its name. See
\code{\link[=guides]{guides()}} for more information.}

\item{position}{For position scales, The position of the axis.
\code{left} or \code{right} for y axes, \code{top} or \code{bottom} for x axes.}

\item{super}{The super class to use for the constructed scale}
}
\description{
Discrete scale constructor
}
\keyword{internal}