niram/dist/helpers/hslToRgb.js

A javascript library to convert between various css colour formats.

import { numberTo2Hex } from './hex.js';
import { normaliseFraction, normaliseDegree } from './normalisers.js';
export function hslToRgb(type, hueDegree, satPercent, levelPercent, alphaFraction = 1) {
    const satFraction = normaliseFraction(Number(satPercent) / 100);
    const levelFraction = normaliseFraction(Number(levelPercent) / 100);
    const c = (1 - Math.abs(2 * levelFraction - 1)) * satFraction;
    const m = levelFraction - c / 2;
    const { red_, green_, blue_ } = getRgbFraction(normaliseDegree(hueDegree), c);
    return {
        type,
        redHex: numberTo2Hex(((red_ + m) * 255).toFixed()),
        greenHex: numberTo2Hex(((green_ + m) * 255).toFixed()),
        blueHex: numberTo2Hex(((blue_ + m) * 255).toFixed()),
        alphaFraction: normaliseFraction(alphaFraction),
    };
}
function getRgbFraction(hueDegree, c) {
    const x = c * (1 - Math.abs(((hueDegree / 60) % 2) - 1));
    if (0 <= hueDegree && hueDegree < 60) {
        return { red_: c, green_: x, blue_: 0 };
    }
    else if (60 <= hueDegree && hueDegree < 120) {
        return { red_: x, green_: c, blue_: 0 };
    }
    else if (120 <= hueDegree && hueDegree < 180) {
        return { red_: 0, green_: c, blue_: x };
    }
    else if (180 <= hueDegree && hueDegree < 240) {
        return { red_: 0, green_: x, blue_: c };
    }
    else if (240 <= hueDegree && hueDegree < 300) {
        return { red_: x, green_: 0, blue_: c };
    }
    else if (300 <= hueDegree && hueDegree < 360) {
        return { red_: c, green_: 0, blue_: x };
    }
    return { red_: 0, green_: 0, blue_: 0 };
}