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.

alpha

The alpha transparency, a number in [0,1], see argument alpha in hsv.

begin

The (corrected) hue in [0,1] at which the color map begins.

end

The (corrected) hue in [0,1] at which the color map ends.

direction

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.

option

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" )