When you select color literals, a palette, or a ggplot2 object, the colors used there will be output in the console.
# install from CRAN
install.packages("seecolor")
# install from GitHub:
devtools::install_github("lovestat/seecolor")# Highlight objects by cursor to show the contained colors
pick_color()
# Change output styles, "ribbon" or "mosaic"
pick_color(type = "r")
# Change the length of the color blocks
pick_color(blank.len = 1)
# Print colors contained in literal, palette and ggplot objects
print_color(colors(), type = "m", blank.len = 1)
# Open the pre-defined test file
open_sample()