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Contents
import { rgb2hue, rgb2value, rgb2whiteness, hue2rgb } from './util';
/* Convert between RGB and HSL
/* ========================================================================== */
export function rgb2hsl(rgbR, rgbG, rgbB, fallbackhue) {
const hslH = rgb2hue(rgbR, rgbG, rgbB, fallbackhue);
const hslV = rgb2value(rgbR, rgbG, rgbB);
const hslW = rgb2whiteness(rgbR, rgbG, rgbB);
// calculate value/whiteness delta
const hslD = hslV - hslW;
// calculate lightness
const hslL = (hslV + hslW) / 2;
// calculate saturation
const hslS = hslD === 0 ? 0 : hslD / (100 - Math.abs(2 * hslL - 100)) * 100;
return [ hslH, hslS, hslL ];
}
export function hsl2rgb(hslH, hslS, hslL) {
// calcuate t2
const t2 = hslL <= 50 ? hslL * (hslS + 100) / 100 : hslL + hslS - hslL * hslS / 100;
// calcuate t1
const t1 = hslL * 2 - t2;
// calculate rgb
const [ rgbR, rgbG, rgbB ] = [
hue2rgb(t1, t2, hslH + 120),
hue2rgb(t1, t2, hslH),
hue2rgb(t1, t2, hslH - 120)
];
return [ rgbR, rgbG, rgbB ];
}
/*
References
----------
- https://www.w3.org/TR/css-color-3/#hsl-color
- https://www.w3.org/TR/css-color-4/#hsl-to-rgb
- https://www.rapidtables.com/convert/color/rgb-to-hsl.html
- https://www.rapidtables.com/convert/color/hsl-to-rgb.html
/* ========================================================================== */
Version data entries
26 entries across 25 versions & 8 rubygems