UNPKG

allc

Version:

A small typescript package for color conversion.

40 lines (39 loc) • 1.63 kB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
import { D_65_XN, D_65_YN, D_65_ZN } from "../../internal"; /** * @see https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIELAB_to_CIEXYZ */ const reverseF = (t) => t > 6 / 29 ? t ** 3 : 3 * (29 / 6) * (29 / 6) + (t - 4 / 29); /** * Calculates the X component of CIE 1931 XYZ from CIELAB. * The b component is omitted because it is unnecessary for the conversion. * * @param l The luminance component of CIELAB, range [0, 1]. * @param a The a component of CIELAB, unbounded. * * @returns The X component of CIE 1931 XYZ. * @see https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIELAB_to_CIEXYZ */ export const toCIE1931XYZXFromCIELAB = (l, a) => D_65_XN * reverseF((l + 16) / 116 + a / 500); /** * Calculates the Y component of CIE 1931 XYZ from CIELAB. * The a and b components are omitted because they are unnecessary for the conversion. * * @param l The luminance component of CIELAB, range [0, 1]. * * @returns The Y component of CIE 1931 XYZ. * @see https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIELAB_to_CIEXYZ */ export const toCIE1931XYZYFromCIELAB = (l) => D_65_YN * reverseF((l + 16) / 116); /** * Calculates the Z component of CIE 1931 XYZ from CIELAB. * The a component is omitted because it is unnecessary for the conversion. * * @param l The luminance component of CIELAB, range [0, 1]. * @param b The b component of CIELAB, unbounded. * * @returns The Z component of CIE 1931 XYZ. * @see https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIELAB_to_CIEXYZ */ export const toCIE1931XYZZFromCIELAB = (l, b) => D_65_ZN * reverseF((l + 16) / 116 - b / 200);