411 REFERENCE · Wikibooks
Rebol Programming/brightness?
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
USAGE:
BRIGHTNESS? color
DESCRIPTION:
Returns the monochrome brightness (0.0 to 1.0) for a color value.
BRIGHTNESS? is a function value.
ARGUMENTS
color -- (Type: tuple)
SOURCE CODE
brightness?: func [
{Returns the monochrome brightness (0.0 to 1.0) for a color value.}
color [tuple!]
][
(0.27 * color/1) + (0.63 * color/2) + (0.1 * color/3) / 255
]