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% Generated by roxygen2 (4.0.1): do not edit by hand
\name{scale_colour_gradient2}
\alias{scale_color_gradient2}
\alias{scale_colour_gradient2}
\alias{scale_fill_gradient2}
\title{Diverging colour gradient}
\usage{
scale_colour_gradient2(..., low = muted("red"), mid = "white",
high = muted("blue"), midpoint = 0, space = "rgb",
na.value = "grey50", guide = "colourbar")
scale_fill_gradient2(..., low = muted("red"), mid = "white",
high = muted("blue"), midpoint = 0, space = "rgb",
na.value = "grey50", guide = "colourbar")
scale_color_gradient2(..., low = muted("red"), mid = "white",
high = muted("blue"), midpoint = 0, space = "rgb",
na.value = "grey50", guide = "colourbar")
}
\arguments{
\item{midpoint}{The midpoint (in data value) of the diverging scale.
Defaults to 0.}
\item{guide}{Type of legend. Use \code{"colourbar"} for continuous
colour bar, or \code{"legend"} for discrete colour legend.}
\item{...}{Other arguments passed on to \code{\link{discrete_scale}}
to control name, limits, breaks, labels and so forth.}
\item{na.value}{Colour to use for missing values}
\item{low}{colour for low end of gradient.}
\item{mid}{colour for mid point}
\item{high}{colour for high end of gradient.}
\item{space}{colour space in which to calculate gradient. "Lab" usually
best unless gradient goes through white.}
}
\description{
Diverging colour gradient
}
\examples{
\donttest{
dsub <- subset(diamonds, x > 5 & x < 6 & y > 5 & y < 6)
dsub$diff <- with(dsub, sqrt(abs(x-y))* sign(x-y))
(d <- qplot(x, y, data=dsub, colour=diff))
d + scale_colour_gradient2()
# Change scale name
d + scale_colour_gradient2(expression(sqrt(abs(x - y))))
d + scale_colour_gradient2("Difference\\nbetween\\nwidth and\\nheight")
# Change limits and colours
d + scale_colour_gradient2(limits=c(-0.2, 0.2))
# Using "muted" colours makes for pleasant graphics
# (and they have better perceptual properties too)
library(scales) # for muted
d + scale_colour_gradient2(low="red", high="blue")
d + scale_colour_gradient2(low=muted("red"), high=muted("blue"))
# Using the Lab colour space also improves perceptual properties
# at the price of slightly slower operation
d + scale_colour_gradient2(space="Lab")
# About 5\% of males are red-green colour blind, so it's a good
# idea to avoid that combination
d + scale_colour_gradient2(high=muted("green"))
# We can also make the middle stand out
d + scale_colour_gradient2(mid=muted("green"), high="white", low="white")
# or use a non zero mid point
(d <- qplot(carat, price, data=diamonds, colour=price/carat))
d + scale_colour_gradient2(midpoint=mean(diamonds$price / diamonds$carat))
# Fill gradients work much the same way
p <- qplot(letters[1:5], 1:5, fill= c(-3, 3, 5, 2, -2), geom = "bar",
stat = "identity")
p + scale_fill_gradient2("fill")
# Note how positive and negative values of the same magnitude
# have similar intensity
}
}
\seealso{
Other colour scales: \code{\link{scale_color_brewer}},
\code{\link{scale_color_distiller}},
\code{\link{scale_colour_brewer}},
\code{\link{scale_colour_distiller}},
\code{\link{scale_fill_brewer}},
\code{\link{scale_fill_distiller}};
\code{\link{scale_color_continuous}},
\code{\link{scale_color_gradient}},
\code{\link{scale_colour_continuous}},
\code{\link{scale_colour_gradient}},
\code{\link{scale_fill_continuous}},
\code{\link{scale_fill_gradient}};
\code{\link{scale_color_discrete}},
\code{\link{scale_color_hue}},
\code{\link{scale_colour_discrete}},
\code{\link{scale_colour_hue}},
\code{\link{scale_fill_discrete}},
\code{\link{scale_fill_hue}};
\code{\link{scale_color_gradientn}},
\code{\link{scale_colour_gradientn}},
\code{\link{scale_fill_gradientn}};
\code{\link{scale_color_grey}},
\code{\link{scale_colour_grey}},
\code{\link{scale_fill_grey}}
}
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