rgb>gray ( r g b -- color )

Vocabulary

io.streams.256color.private

Inputs

r	an object
g	an object
b	an object

Outputs

color

an object

Definition

USING: combinators math math.order ;

IN: io.streams.256color.private

:: rgb>gray ( r g b -- color )
    {
        { [ r 0 4 between? ] [ 16 ] }
        { [ r 5 8 between? ] [ 232 ] }
        { [ r 238 246 between? ] [ 255 ] }
        { [ r 247 255 between? ] [ 231 ] }
        [ r 8 - 10 /i 232 + ]
    } cond ;