chroma-js/src/io/css/css2rgb.js

JavaScript library for color conversions

const hsl2rgb = require('../hsl/hsl2rgb');
const input = require('../input');

const RE_RGB = /^rgb\(\s*(-?\d+),\s*(-?\d+)\s*,\s*(-?\d+)\s*\)$/;
const RE_RGBA = /^rgba\(\s*(-?\d+),\s*(-?\d+)\s*,\s*(-?\d+)\s*,\s*([01]|[01]?\.\d+)\)$/;
const RE_RGB_PCT = /^rgb\(\s*(-?\d+(?:\.\d+)?)%,\s*(-?\d+(?:\.\d+)?)%\s*,\s*(-?\d+(?:\.\d+)?)%\s*\)$/;
const RE_RGBA_PCT = /^rgba\(\s*(-?\d+(?:\.\d+)?)%,\s*(-?\d+(?:\.\d+)?)%\s*,\s*(-?\d+(?:\.\d+)?)%\s*,\s*([01]|[01]?\.\d+)\)$/;
const RE_HSL = /^hsl\(\s*(-?\d+(?:\.\d+)?),\s*(-?\d+(?:\.\d+)?)%\s*,\s*(-?\d+(?:\.\d+)?)%\s*\)$/;
const RE_HSLA = /^hsla\(\s*(-?\d+(?:\.\d+)?),\s*(-?\d+(?:\.\d+)?)%\s*,\s*(-?\d+(?:\.\d+)?)%\s*,\s*([01]|[01]?\.\d+)\)$/;

const {round} = Math;

const css2rgb = (css) => {
    css = css.toLowerCase().trim();
    let m;

    if (input.format.named) {
        try {
            return input.format.named(css);
        } catch (e) {
            // eslint-disable-next-line
        }
    }

    // rgb(250,20,0)
    if ((m = css.match(RE_RGB))) {
        const rgb = m.slice(1,4);
        for (let i=0; i<3; i++) {
            rgb[i] = +rgb[i];
        }
        rgb[3] = 1;  // default alpha
        return rgb;
    }

    // rgba(250,20,0,0.4)
    if ((m = css.match(RE_RGBA))) {
        const rgb = m.slice(1,5);
        for (let i=0; i<4; i++) {
            rgb[i] = +rgb[i]
        }
        return rgb;
    }

    // rgb(100%,0%,0%)
    if ((m = css.match(RE_RGB_PCT))) {
        const rgb = m.slice(1,4);
        for (let i=0; i<3; i++) {
            rgb[i] = round(rgb[i] * 2.55);
        }
        rgb[3] = 1;  // default alpha
        return rgb;
    }

    // rgba(100%,0%,0%,0.4)
    if ((m = css.match(RE_RGBA_PCT))) {
        const rgb = m.slice(1,5);
        for (let i=0; i<3; i++) {
            rgb[i] = round(rgb[i] * 2.55);
        }
        rgb[3] = +rgb[3];
        return rgb;
    }

    // hsl(0,100%,50%)
    if ((m = css.match(RE_HSL))) {
        const hsl = m.slice(1,4);
        hsl[1] *= 0.01;
        hsl[2] *= 0.01;
        const rgb = hsl2rgb(hsl);
        rgb[3] = 1;
        return rgb;
    }

    // hsla(0,100%,50%,0.5)
    if ((m = css.match(RE_HSLA))) {
        const hsl = m.slice(1,4);
        hsl[1] *= 0.01;
        hsl[2] *= 0.01;
        const rgb = hsl2rgb(hsl);
        rgb[3] = +m[4]  // default alpha = 1
        return rgb;
    }
}

css2rgb.test = (s) => {
    return RE_RGB.test(s) ||
        RE_RGBA.test(s) ||
        RE_RGB_PCT.test(s) ||
        RE_RGBA_PCT.test(s) ||
        RE_HSL.test(s) ||
        RE_HSLA.test(s);
}

module.exports = css2rgb;