geom_tile.Rd

% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/geom-raster.r, R/geom-rect.r, R/geom-tile.r
\name{geom_raster}
\alias{geom_raster}
\alias{geom_rect}
\alias{geom_tile}
\title{Draw rectangles.}
\usage{
geom_raster(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", hjust = 0.5, vjust = 0.5, interpolate = FALSE,
  show.legend = NA, inherit.aes = TRUE, ...)

geom_rect(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", show.legend = NA, inherit.aes = TRUE, ...)

geom_tile(mapping = NULL, data = NULL, stat = "identity",
  position = "identity", show.legend = NA, inherit.aes = TRUE, ...)
}
\arguments{
\item{mapping}{Set of aesthetic mappings created by \code{\link{aes}} or
\code{\link{aes_}}. If specified and \code{inherit.aes = TRUE} (the
default), is combined with the default mapping at the top level of the
plot. You only need to supply \code{mapping} if there isn't a mapping
defined for the plot.}

\item{data}{A data frame. If specified, overrides the default data frame
defined at the top level of the plot.}

\item{stat}{The statistical transformation to use on the data for this
layer, as a string.}

\item{position}{Position adjustment, either as a string, or the result of
a call to a position adjustment function.}

\item{hjust,vjust}{horizontal and vertical justification of the grob.  Each
justification value should be a number between 0 and 1.  Defaults to 0.5
for both, centering each pixel over its data location.}

\item{interpolate}{If \code{TRUE} interpolate linearly, if \code{FALSE}
(the default) don't interpolate.}

\item{show.legend}{logical. Should this layer be included in the legends?
\code{NA}, the default, includes if any aesthetics are mapped.
\code{FALSE} never includes, and \code{TRUE} always includes.}

\item{inherit.aes}{If \code{FALSE}, overrides the default aesthetics,
rather than combining with them. This is most useful for helper functions
that define both data and aesthetics and shouldn't inherit behaviour from
the default plot specification, e.g. \code{\link{borders}}.}

\item{...}{other arguments passed on to \code{\link{layer}}. There are
  three types of arguments you can use here:

  \itemize{
  \item Aesthetics: to set an aesthetic to a fixed value, like
     \code{color = "red"} or \code{size = 3}.
  \item Other arguments to the layer, for example you override the
    default \code{stat} associated with the layer.
  \item Other arguments passed on to the stat.
  }}
}
\description{
\code{geom_rect} and \code{geom_tile} do the same thing, but are
paramterised differently. \code{geom_rect} uses the locations of the four
corners (\code{xmin}, \code{xmax}, \code{ymin} and \code{ymax}).
\code{geom_tile} uses the center of the tile and it's size (\code{x},
\code{y}, \code{width}, \code{height}). \code{geom_raster} is a high
performance special case for when all the tiles are the same size.
}
\section{Aesthetics}{

\Sexpr[results=rd,stage=build]{ggplot2:::rd_aesthetics("geom", "tile")}
}
\examples{
# The most common use for rectangles is to draw a surface. You always want
# to use geom_raster here because it's so much faster, and produces
# smaller output when saving to PDF
ggplot(faithfuld, aes(waiting, eruptions)) +
 geom_raster(aes(fill = density))

# Interpolation smooths the surface & is most helpful when rendering images.
ggplot(faithfuld, aes(waiting, eruptions)) +
 geom_raster(aes(fill = density), interpolate = TRUE)

# If you want to draw arbitrary rectangles, use geom_tile() or geom_rect()
df <- data.frame(
  x = rep(c(2, 5, 7, 9, 12), 2),
  y = rep(c(1, 2), each = 5),
  z = factor(rep(1:5, each = 2)),
  w = rep(diff(c(0, 4, 6, 8, 10, 14)), 2)
)
ggplot(df, aes(x, y)) +
  geom_tile(aes(fill = z))
ggplot(df, aes(x, y)) +
  geom_tile(aes(fill = z, width = w), colour = "grey50")
ggplot(df, aes(xmin = x - w / 2, xmax = x + w / 2, ymin = y, ymax = y + 1)) +
  geom_rect(aes(fill = z, width = w), colour = "grey50")

\donttest{
# Justification controls where the cells are anchored
df <- expand.grid(x = 0:5, y = 0:5)
df$z <- runif(nrow(df))
# default is compatible with geom_tile()
ggplot(df, aes(x, y, fill = z)) + geom_raster()
# zero padding
ggplot(df, aes(x, y, fill = z)) + geom_raster(hjust = 0, vjust = 0)

# Inspired by the image-density plots of Ken Knoblauch
cars <- ggplot(mtcars, aes(mpg, factor(cyl)))
cars + geom_point()
cars + stat_bin2d(aes(fill = ..count..), binwidth = c(3,1))
cars + stat_bin2d(aes(fill = ..density..), binwidth = c(3,1))

cars + stat_density(aes(fill = ..density..), geom = "raster", position = "identity")
cars + stat_density(aes(fill = ..count..), geom = "raster", position = "identity")
}
}