chroma-js
Version:
JavaScript library for color conversions
32 lines (21 loc) • 852 B
text/coffeescript
lab2rgb = () ->
args = unpack arguments
[] = args
y = (l + 16) / 116
x = if isNaN(a) then y else y + a / 500
z = if isNaN(b) then y else y - b / 200
y = LAB_CONSTANTS.Yn * lab_xyz y
x = LAB_CONSTANTS.Xn * lab_xyz x
z = LAB_CONSTANTS.Zn * lab_xyz z
r = xyz_rgb 3.2404542 * x - 1.5371385 * y - 0.4985314 * z
g = xyz_rgb -0.9692660 * x + 1.8760108 * y + 0.0415560 * z
b = xyz_rgb 0.0556434 * x - 0.2040259 * y + 1.0572252 * z
r = limit r,0,255
g = limit g,0,255
b = limit b,0,255
[] else 1]
xyz_rgb = (r) ->
round(255 * (if r <= 0.00304 then 12.92 * r else 1.055 * pow(r, 1 / 2.4) - 0.055))
lab_xyz = (t) ->
if t > LAB_CONSTANTS.t1 then t * t * t else LAB_CONSTANTS.t2 * (t - LAB_CONSTANTS.t0)