Emulate Ggplot2 Default Color Palette
What Function Can I Use to Emulate Ggplot2'S Default Color Palette for a Desired Number of Colors. for Example, an Input of 3 Would Produce a Character Vector...
What function can I use to emulate ggplot2's default color palette for a desired number of colors. For example, an input of 3 would produce a character vector of HEX colors with these colors:
4 Answers
It is just equally spaced hues around the color wheel, starting from 15:
gg_color_hue <- function(n) {
hues = seq(15, 375, length = n + 1)
hcl(h = hues, l = 65, c = 100)[1:n]
}
For example:
n = 4
cols = gg_color_hue(n)
dev.new(width = 4, height = 4)
plot(1:n, pch = 16, cex = 2, col = cols)
This is the result from
library(scales)
show_col(hue_pal()(4))
show_col(hue_pal()(3))
These answers are all very good, but I wanted to share another thing I discovered on stackoverflow that is really quite useful, here is the direct link
Basically, @DidzisElferts shows how you can get all the colours, coordinates, etc that ggplot uses to build a plot you created. Very nice!
p <- ggplot(mpg,aes(x=class,fill=class)) + geom_bar()
ggplot_build(p)$data
[[1]]
fill y count x ndensity ncount density PANEL group ymin ymax xmin xmax
1 #F8766D 5 5 1 1 1 1.111111 1 1 0 5 0.55 1.45
2 #C49A00 47 47 2 1 1 1.111111 1 2 0 47 1.55 2.45
3 #53B400 41 41 3 1 1 1.111111 1 3 0 41 2.55 3.45
4 #00C094 11 11 4 1 1 1.111111 1 4 0 11 3.55 4.45
5 #00B6EB 33 33 5 1 1 1.111111 1 5 0 33 4.55 5.45
6 #A58AFF 35 35 6 1 1 1.111111 1 6 0 35 5.55 6.45
7 #FB61D7 62 62 7 1 1 1.111111 1 7 0 62 6.55 7.45
From page 106 of the ggplot2 book by Hadley Wickham:
The default colour scheme, scale_colour_hue picks evenly spaced hues around the hcl colour wheel.
With a bit of reverse engineering you can construct this function:
ggplotColours <- function(n = 6, h = c(0, 360) + 15){
if ((diff(h) %% 360) < 1) h[2] <- h[2] - 360/n
hcl(h = (seq(h[1], h[2], length = n)), c = 100, l = 65)
}
Demonstrating this in barplot:
y <- 1:3
barplot(y, col = ggplotColours(n = 3))
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