transparent
is a simple little R library that allows us to conveniently set the alpha level of any of the standard R colours. It also has a few little functions that wrap the graphics::polygon
function and allow us to add circles and rectangles to plots.
Install the library directly from github using the devtools
library:
devtools::install_github("ram6ler/transparent")
Here is a little script that adds 20 randomly coloured circles to a plot. Notice that the fills are the same colour as the borders and texts, only transparent.
library(transparent)
# create an empty plot
par(mar = c(0, 0, 0, 0))
plot.new()
plot.window(xlim = c(0, 1), ylim = c(0, 1))
# start adding circles...
n <- 20
for (j in 1:n) {
# circle centre
x <- runif(1)
y <- runif(1)
# circle radius
r <- runif(1) * 0.15 + 0.025
# a random standard colour
rand_col <- sample(colors(), 1)
# the colour, with alpha level lowered
fill_col <- setAlpha(rand_col, 0.2)
# draw a circle using the colours
circle(x, y, r, border = rand_col, col = fill_col)
# insert the name of the colour as a label
text(x, y, labels = rand_col, col = rand_col, cex = r * 10)
}