setCLranges: Get Chroma and Luminance ranges for the given lightMode
In jmw86069/jamba: Jam Base Methods

setCLranges

R Documentation

Get Chroma and Luminance ranges for the given lightMode

Description

Return Crange, Lrange, Cgrey, adjustRgb values for the given lightMode, intended to provide ranges suitable for contrasting text displayed on a light or dark background.

Usage

setCLranges(
  lightMode = NULL,
  Crange = getOption("jam.Crange"),
  Lrange = getOption("jam.Lrange"),
  Cgrey = getOption("jam.Cgrey", 5),
  adjustRgb = getOption("jam.adjustRgb", 0),
  setOptions = c("FALSE", "ifnull", "TRUE"),
  verbose = FALSE,
  ...
)

Arguments

`lightMode`	boolean indicating whether the background color is light (TRUE is bright), or dark (FALSE is dark.) By default it calls `checkLightMode()` which queries `getOption("lightMode")`.
`Crange`	numeric range of chroma values, ranging between 0 and 100. By default, `getOptions("Crange")` is used, otherwise defaults will be assigned based upon `lightMode`.
`Lrange`	numeric range of luminance values, ranging between 0 and 100. By default, `getOptions("Crange")` is used, otherwise defaults will be assigned based upon `lightMode`.
`Cgrey`	numeric chroma (C) value, which defines grey colors at or below this chroma. Any colors at or below the grey cutoff will have their C values unchanged. This mechanism prevents converting black to red, for example. To disable the effect, set `Cgrey=-1`.
`adjustRgb`	numeric color adjustment factor, used during the conversion of RGB colors to the ANSI-compatible colors used by the `crayon` pacakge. The ANSI color range does not include a full RGB palette, and the conversion is somewhat lossy. By default, `getOptions("jam.adjustRgb")` is used to store a globally re-usable value.
`setOptions`	character or logical whether to update `options()` `"jam.Crange"` and `"jam.Lrange"`, with the following behavior: `"ifnull"` will update only `options()` which were previously `NULL` `FALSE` or `"FALSE"` does not update `options()` `TRUE` or `"TRUE"` will update `options()` with values determined by this function.
`verbose`	`logical` indicating whether to print verbose output.
`...`	additional arguments are ignored.

Details

This function is intended mainly for internal use by jamba such as printDebug(), and make_styles(), which is also mainly intended for console text or other printed text output. The utility of this function is to store the logic of determining sensible default ranges.

Companion functions:

applyCLranges() is used to apply the ranges to a vector of R colors.
checkLightMode() is used to detect whether console output is expected to have a light or dark background.

Value

list with elements:

Crange: Numeric vector of length 2, defining the HCL chroma (C) range.
Lrange: Numeric vector of length 2, defining the HCL luminance (L) range.
adjustRgb: Numeric vector of length 1, defining the adjustment to apply during RGB-to-ANSI color conversion.
Cgrey: Numeric vector of length 1, defining the HCL chroma (C) value below which colors are considered greyscale, and are converted to ANSI greyscale colors. HCL chroma ranges from 0 to 100. Set value Cgrey=-1 or Cgrey=FALSE to disable this logic, causing colors to be matched using all available ANSI color values.