Matplotlib 'viridis' color map
This function creates a vector of
n equally spaced colors along the
Matplolib 'viridis' color map created by Stéfan van der Walt
and Nathaniel Smith. This color map is
designed in such a way that it will analytically be perfectly perceptually-uniform,
both in regular form and also when converted to black-and-white. It is also
designed to be perceived by readers with the most common form of color blindness.
viridis(n, alpha = 1, begin = 0, end = 1, option = "D")viridisMap(n = 256, alpha = 1, begin = 0, end = 1, option = "D")magma(n, alpha = 1, begin = 0, end = 1)inferno(n, alpha = 1, begin = 0, end = 1)plasma(n, alpha = 1, begin = 0, end = 1)
- The number of colors ($\ge 1$) to be in the palette.
- The alpha transparency, a number in [0,1], see argument alpha in
- The (corrected) hue in [0,1] at which the viridis colormap begins.
- The (corrected) hue in [0,1] at which the viridis colormap ends.
- A character string indicating the colormap option to use. Four options are available: "magma" (or "A"), "inferno" (or "B"), "plasma" (or "C"), and "viridis" (or "D", the default option).
Here are the color scales:
inferno() are convenience
functions for the other colormap options, which are useful the scale must
be passed as a function name.
Semi-transparent colors ($0 < alpha < 1$) are supported only on some
viridisreturns a character vector,
cv, of color hex codes. This can be used either to create a user-defined color palette for subsequent graphics by
col =specification in graphics functions or in
nlines data frame containing the red (
R), green (
G), blue (
B) and alpha (
alpha) channels of
nequally spaced colors along the 'viridis' color map.
n = 256by default, which corresponds to the data from the original 'viridis' color map in Matplotlib.
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" )