hwba
HWB colors

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<hwba> ( hue whiteness blackness alpha -- hwba )

Vocabulary
colors.hwb

Class description
The class of HWB (Hue, Whiteness, Blackness) colors with an alpha channel. All slots store values in the interval [0,1].

Definition

IN: colors.hwb

TUPLE: hwba
    { hue read-only } { whiteness read-only }
    { blackness read-only } { alpha read-only } ;

Methods

USING: colors.hwb ;

M: hwba >hwba ; inline


USING: accessors colors colors.gray colors.hsl colors.hwb kernel
locals.backend math ;

M: hwba >rgba
    [ hue>> ] keep [ whiteness>> ] keep [ blackness>> ] keep
    [ alpha>> ] keep drop 4 load-locals
    -2 get-local -1 get-local + load-local 0 get-local 1 >=
    -3 get-local 0 get-local -1 get-local [
        3 load-locals -2 get-local -1 get-local /
        0 get-local <gray> 3 drop-locals
    ] curry curry curry
    -4 get-local -1 get-local 0 get-local -3 get-local [
        4 load-locals -3 get-local 1.0 0.5 -2 get-local <hsla>
        >rgba-components -1 get-local 0 get-local [
            2 load-locals -1 get-local 0 get-local [
                2 load-locals 1 -1 get-local - * 0 get-local +
                2 drop-locals
            ] curry curry tri@ 2 drop-locals
        ] curry curry dip <rgba> 4 drop-locals
    ] curry curry curry curry if 5 drop-locals ; inline