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

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

n The number of colors ($$\ge 1$$) to be in the palette. The alpha transparency, a number in [0,1], see argument alpha in hsv. The (corrected) hue in [0,1] at which the color map begins. The (corrected) hue in [0,1] at which the color map ends. Sets the order of colors in the scale. If 1, the default, colors are ordered from darkest to lightest. If -1, the order of colors is reversed. A character string indicating the color map option to use. Eight options are available: "magma" (or "A") "inferno" (or "B") "plasma" (or "C") "viridis" (or "D") "cividis" (or "E") "rocket" (or "F") "mako" (or "G") "turbo" (or "H")

## 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.

## 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.

## Author

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"
)