source: trip-planner-front/node_modules/@csstools/convert-colors/lib/rgb-hsv.js@ 188ee53

import { rgb2value, rgb2whiteness, rgb2hue } from './util';

/* Convert between RGB and HSV
/* ========================================================================== */

export function rgb2hsv(rgbR, rgbG, rgbB, fallbackhue) {
        const hsvV = rgb2value(rgbR, rgbG, rgbB);
        const hsvW = rgb2whiteness(rgbR, rgbG, rgbB);
        const hsvH = rgb2hue(rgbR, rgbG, rgbB, fallbackhue);

        // calculate saturation
        const hsvS = hsvV === hsvW ? 0 : (hsvV - hsvW) / hsvV * 100;

        return [ hsvH, hsvS, hsvV ];
}

export function hsv2rgb(hsvH, hsvS, hsvV) {
        const rgbI = Math.floor(hsvH / 60);

        // calculate rgb parts
        const rgbF = hsvH / 60 - rgbI & 1 ? hsvH / 60 - rgbI : 1 - hsvH / 60 - rgbI;
        const rgbM = hsvV * (100 - hsvS) / 100;
        const rgbN = hsvV * (100 - hsvS * rgbF) / 100;

        const [ rgbR, rgbG, rgbB ] = rgbI === 5
                ? [ hsvV, rgbM, rgbN ]
        : rgbI === 4
                ? [ rgbN, rgbM, hsvV ]
        : rgbI === 3
                ? [ rgbM, rgbN, hsvV ]
        : rgbI === 2
                ? [ rgbM, hsvV, rgbN ]
        : rgbI === 1
                ? [ rgbN, hsvV, rgbM ]
        : [ hsvV, rgbN, rgbM ];

        return [ rgbR, rgbG, rgbB ];
}

/*

References
----------

- http://alvyray.com/Papers/CG/hsv2rgb.htm

/* ========================================================================== */