color_dither function

Make dithered color pattern light-dark

color_dither(
  x,
  L_diff = 4,
  L_max = 90,
  L_min = 30,
  min_contrast = 1.25,
  direction = 1,
  returnType = c("vector", "list", "matrix"),
  debug = FALSE,
  ...
)

Arguments

• x: character vector of R colors

• L_diff: numeric value added or subtracted from the L in HSL color space for each color, until contrast is at least min_contrast.

• L_max, L_min: numeric values that define the permitted range of L values in HSL color space, which ranges from 0 to 100.

• min_contrast: numeric minimum contrast as defined by colorspace::contrast_ratio() for the input and potential output color.

• direction: numeric that defines the initial direction, where values >= 0 start by making colors lighter, and values < 0 make colors darker.

• returnType: character string that defines the output of this function:

  • vector: two colors for every input color in x
  • matrix: two rows, input colors on first row, output colors on second row
  • list: a list with two colors in each element, with input and output colors together in each vector.

• debug: logical indicating whether to plot the color iterations using showColors().

• ...: additional arguments are ignored.

Returns

format defined by argument returnType:

• vector: two colors for every input color in x
• matrix: two rows, input colors on first row, output colors on second row
• list: a list with two colors in each element, with input and output colors together in each vector.

Details

This function serves a very simple purpose, mainly for printDebug() to use subtle alternating light/dark colors for vector output. It takes a color and returns two colors which are slightly lighter and darker than each other, to a minimum contrast defined by colorspace::contrast_ratio().

Examples

x <- "firebrick1";
showColors(color_dither(x))

showColors(color_dither(x, direction=-1))

x <- vigrep("^green[0-9]", grDevices::colors())
showColors(color_dither(x))
showColors(color_dither(x, direction=-1, returnType="list"))

x <- c("green1", "cyan", "blue", "red", "gold", "yellow", "pink")
showColors(color_dither(x))

color_dither(x, debug=TRUE)

See Also

Other jam practical functions: breakDensity(), call_fn_ellipsis(), checkLightMode(), check_pkg_installed(), colNum2excelName(), exp2signed(), getAxisLabel(), isFALSEV(), isTRUEV(), jargs(), kable_coloring(), lldf(), log2signed(), middle(), minorLogTicks(), newestFile(), printDebug(), reload_rmarkdown_cache(), renameColumn(), rmInfinite(), rmNA(), rmNAs(), rmNULL(), setPrompt()