Identify a suitable font color (black or white) given a background HEX color

You could use auto_contrast as a shortcut of aes(colour = after_scale(hex_bw(.data$fill))). You should use !!! to inject it within ggplot2::aes() (see examples).

hex_bw_threshold() is a variation of hex_bw(). For values below threshold, black ("#000000") will always be returned, regardless of hex_code.

Usage

hex_bw(hex_code)

hex_bw_threshold(hex_code, values, threshold)

auto_contrast

Format

An object of class uneval of length 1.

Source

Adapted from saros for hex_code() and from https://github.com/teunbrand/ggplot_tricks?tab=readme-ov-file#text-contrast for auto_contrast.

Arguments

hex_code

Background color in hex-format.

values

Values to be compared.

threshold

Threshold.

Value

Either black or white, in hex-format

Examples

hex_bw("#0dadfd")
#> [1] "#000000"

library(ggplot2)
ggplot(diamonds) +
  aes(x = cut, fill = color, label = after_stat(count)) +
  geom_bar() +
  geom_text(
    mapping = aes(color = after_scale(hex_bw(.data$fill))),
    position = position_stack(.5),
    stat = "count",
    size = 2
  )


ggplot(diamonds) +
  aes(x = cut, fill = color, label = after_stat(count)) +
  geom_bar() +
  geom_text(
    mapping = auto_contrast,
    position = position_stack(.5),
    stat = "count",
    size = 2
  )


ggplot(diamonds) +
  aes(x = cut, fill = color, label = after_stat(count), !!!auto_contrast) +
  geom_bar() +
  geom_text(
    mapping = auto_contrast,
    position = position_stack(.5),
    stat = "count",
    size = 2
  )