Viridis Color Palettes

Description

This function creates a vector of n equally spaced colors along the selected color map.

Usage

viridis(n, alpha = 1, begin = 0, end = 1, direction = 1, option = "D")

viridisMap(n = 256, alpha = 1, begin = 0, end = 1, direction = 1, option = "D")

magma(n, alpha = 1, begin = 0, end = 1, direction = 1)

inferno(n, alpha = 1, begin = 0, end = 1, direction = 1)

plasma(n, alpha = 1, begin = 0, end = 1, direction = 1)

cividis(n, alpha = 1, begin = 0, end = 1, direction = 1)

rocket(n, alpha = 1, begin = 0, end = 1, direction = 1)

mako(n, alpha = 1, begin = 0, end = 1, direction = 1)

turbo(n, alpha = 1, begin = 0, end = 1, direction = 1)

Arguments

Details

Here are the color scales:

magma(), plasma(), inferno(), cividis(), rocket(), mako(), and turbo() are convenience functions for the other color map options, which are useful when the scale must be passed as a function name.

Semi-transparent colors ($0 < alpha < 1$) are supported only on some devices: see rgb.

Value

viridis returns a character vector, cv, of color hex codes. This can be used either to create a user-defined color palette for subsequent graphics by palette(cv), a col = specification in graphics functions or in par.

viridisMap returns a n lines data frame containing the red (R), green (G), blue (B) and alpha (alpha) channels of n equally spaced colors along the selected color map. n = 256 by default.

Author(s)

Simon Garnier: garnier@njit.edu / @sjmgarnier

Examples

library(ggplot2)
library(hexbin)

dat <- data.frame(x = rnorm(10000), y = rnorm(10000))

ggplot(dat, aes(x = x, y = y)) +
  geom_hex() + coord_fixed() +
  scale_fill_gradientn(colours = viridis(256, option = "D"))

# using code from RColorBrewer to demo the palette
n = 200
image(
  1:n, 1, as.matrix(1:n),
  col = viridis(n, option = "D"),
  xlab = "viridis n", ylab = "", xaxt = "n", yaxt = "n", bty = "n"
)

Color Map Data

Description

A data set containing the RGB values of the color maps included in the package. These are:

• 'magma', 'inferno', 'plasma', and 'viridis' as defined in Matplotlib for Python. These color maps are designed in such a way that they will analytically be perfectly perceptually-uniform, both in regular form and also when converted to black-and-white. They are also designed to be perceived by readers with the most common form of color blindness. They were created by Stéfan van der Walt and Nathaniel Smith;

• 'cividis', a corrected version of 'viridis', 'cividis', developed by Jamie R. Nuñez, Christopher R. Anderton, and Ryan S. Renslow, and originally ported to R by Marco Sciaini. It is designed to be perceived by readers with all forms of color blindness;

• 'rocket' and 'mako' as defined in Seaborn for Python;

• 'turbo', an improved Jet rainbow color map for reducing false detail, banding and color blindness ambiguity.

Usage

viridis.map

Format

A data frame with 2048 rows and 4 variables:

• R: Red value;

• G: Green value;

• B: Blue value;

• opt: The colormap "option" (A: magma; B: inferno; C: plasma; D: viridis; E: cividis; F: rocket; G: mako; H: turbo).

Author(s)

Simon Garnier: garnier@njit.edu / @sjmgarnier

References

• 'magma', 'inferno', 'plasma', and 'viridis': https://bids.github.io/colormap/

• 'cividis': https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199239

• 'rocket' and 'mako': https://seaborn.pydata.org/index.html

• 'turbo': https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html