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A safe discrete colour palette

Source: R/safe_pal.R
safe_pal.Rd

Provides a safe colour palette for categorical variable. It is based on Paul Tol's colour schemes designed to be distinct for all people, including colour-blind readers, distinct from black and white, distinct on screen and paper, and matching well together. It is primarily based on the bright colour scheme implemented in khroma::scale_fill_bright(). This colour scheme include 7 colours, including a grey reserved for NA values. Therefore, scale_fill_safe() use the bright scheme only if 6 or less colours are needed (keeping the grey for any NA value). If 7 to 9 colours are needed, the muted scheme (cf. khroma::scale_fill_muted()) is used instead. Finally, if 10 or more colours are requested, the rainbow scheme is used (cf. khroma::scale_fill_discreterainbow()). This is a sequential colour scheme. Here, colour are randomly reordered to provide more contrasts between modalities.

Usage

safe_pal(reverse = FALSE)

scale_fill_safe(
  name = ggplot2::waiver(),
  ...,
  reverse = FALSE,
  aesthetics = "fill",
  na.value = "#BBBBBB"
)

scale_colour_safe(
  name = ggplot2::waiver(),
  ...,
  reverse = FALSE,
  aesthetics = "colour",
  na.value = "#BBBBBB"
)

scale_color_safe(
  name = ggplot2::waiver(),
  ...,
  reverse = FALSE,
  aesthetics = "colour",
  na.value = "#BBBBBB"
)

Arguments

reverse

A logical scalar: should the resulting vector of colours be reversed?

name

The name of the scale. Used as the axis or legend title. If ggplot2::waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

...

Other arguments passed on to discrete_scale() to control name, limits, breaks, labels and so forth.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the colour and fill aesthetics at the same time, via aesthetics = c("colour", "fill").

na.value

Colour to be used for NA values (if any).

Value

A palette function.

Examples


scales::show_col(safe_pal()(6))

scales::show_col(safe_pal(reverse = TRUE)(6))

scales::show_col(safe_pal()(9))

scales::show_col(safe_pal()(16))


ggplot2::ggplot(titanic) +
  ggplot2::aes(x = Age, fill = Class) +
  ggplot2::geom_bar() +
  scale_fill_safe()


ggplot2::ggplot(iris) +
  ggplot2::aes(x = Petal.Length, y = Petal.Width, colour = Species) +
  ggplot2::geom_point(size = 3) +
  scale_colour_safe()