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Create an ANSI color style

Source: R/machinery.R
make_style.Rd

Create a style, or a style function, or both. This function is intended for those who wish to use 256 ANSI colors, instead of the more widely supported eight colors.

Usage

make_style(..., bg = FALSE, grey = FALSE, colors = num_colors())

Arguments

...

The style to create. See details and examples below.

bg

Whether the color applies to the background.

grey

Whether to specifically create a grey color. This flag is included because ANSI 256 has a finer color scale for greys than the usual 0:5 scale for R, G and B components. It is only used for RGB color specifications (either numerically or via a hexa string) and is ignored on eigth color ANSI terminals.

colors

Number of colors, detected automatically by default.

Value

A function that can be used to color strings.

Details

The crayon package comes with predefined styles (see styles() for a list) and functions for the basic eight-color ANSI standard (red, blue, etc., see crayon).

There are no predefined styles or style functions for the 256 color ANSI mode, however, because we simply did not want to create that many styles and functions. Instead, make_style() can be used to create a style (or a style function, or both).

There are two ways to use this function:

  1. If its first argument is not named, then it returns a function that can be used to color strings.

  2. If its first argument is named, then it also creates a style with the given name. This style can be used in style(). One can still use the return value of the function, to create a style function.

The style (the ... argument) can be anything of the following:

  • An R color name, see colors().

  • A 6- or 8-digit hexa color string, e.g. #ff0000 means red. Transparency (alpha channel) values are ignored.

  • A one-column matrix with three rows for the red, green and blue channels, as returned by col2rgb (in the base grDevices package).

make_style() detects the number of colors to use automatically (this can be overridden using the colors argument). If the number of colors is less than 256 (detected or given), then it falls back to the color in the ANSI eight color mode that is closest to the specified (RGB or R) color.

See the examples below.

See also

Other styles: drop_style()

Examples

## Create a style function without creating a style
pink <- make_style("pink")
bgMaroon <- make_style(rgb(0.93, 0.19, 0.65), bg = TRUE)
cat(bgMaroon(pink("I am pink if your terminal wants it, too.\n")))
#> I am pink if your terminal wants it, too.
#> 

## Create a new style for pink and maroon background
make_style(pink = "pink")
#> Crayon style function, pink: example output.
make_style(bgMaroon = rgb(0.93, 0.19, 0.65), bg = TRUE)
#> Crayon style function, bgMaroon: example output.
"pink" %in% names(styles())
#> [1] TRUE
"bgMaroon" %in% names(styles())
#> [1] TRUE
cat(style("I am pink, too!\n", "pink", bg = "bgMaroon"))
#> I am pink, too!
#>