The munsell
package provides easy access to, and
manipulation of, the Munsell colours. The munsell
package
provides a mapping between Munsell’s original notation (e.g. “5R 5/10”)
and hexadecimal sRGB strings suitable for use directly in R graphics.
The package also provides utilities to explore slices through the
Munsell colour tree, to transform Munsell colours and display colour
palettes.
Munsell devised his system of colour notation to match the three perceptual dimensions of colour: hue, value and chroma. His notation provides a naming scheme to colours that eases the choice of color according to a specific purpose. His century old advice is still relevant for the producers of statistical graphics and the munsell package aims to enable user to easily follow it.
Functions in munsell
fall into three basic use
categories: specifying Munsell colours, altering Munsell colours and
exploring the Munsell color space.
The code below relies on the development version of
munsell
, get it with:
::install_github("cwickham/munsell") devtools
Following Munsell, specifying colours is done with a specific string
format: “H V/C” where H is a hue code (see mnsl_hues()
for
a list of those available, excluding “N”), V an integer in ([0, 10])
specifying value, and C an even integer specifying chroma. The
mnsl
function takes the string and returns a hexadecimal
RGB representation:
library(munsell)
mnsl("5R 5/10")
#> [1] "#C65858"
Visually examining a colour can either be done by using
mnsl
with a base plotting call, or using
plot_mnsl
which plots colour swatches using
ggplot2
:
plot.new()
rect(0, 0, 1 ,1 , col = mnsl("5R 5/10"))
plot_mnsl("5R 5/10")
munsell
provides convenience functions that alter a
colour by taking steps in the hue, value and chroma dimensions:
rygbp
, pbgyr
, lighter
,
darker
, saturate
and
desaturate
.
<- "5PB 5/8"
my_blue <- plot_mnsl(c(
p lighter(my_blue, 2), my_blue, darker(my_blue, 2),
desaturate(my_blue, 2), my_blue, saturate(my_blue, 2),
rygbp(my_blue, 2), my_blue, pbgyr(my_blue, 2)))
p
Each function optionally takes the number of steps to take in the dimension and consequently are easily used to create scales in a particular dimension.
<- plot_mnsl(sapply(0:6, darker, col = "5PB 7/4"))
p + ggplot2::facet_wrap(~ num, nrow = 1) p
Slices through the colour space of constant hue, chroma or value can
be displayed using the functions: hue_slice
,
chroma_slice
and value_slice
. Additionally
complement_slice
displays a slice of constant hue,
alongside a slice of its complement, the hue that is on the opposite
side of the colour sphere to that specified.
complement_slice("5R")