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 liuqimichale
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// HSL to RGB converter. Both methods adapted from:
// http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
function hslToRgb(h, s, l) {
var r, g, b;
// normalize hue orientation b/w 0 and 360 degrees
h = h % 360;
if (h < 0)
h += 360;
h = ~~h / 360;
if (s < 0)
s = 0;
else if (s > 100)
s = 100;
s = ~~s / 100;
if (l < 0)
l = 0;
else if (l > 100)
l = 100;
l = ~~l / 100;
if (s === 0) {
r = g = b = l; // achromatic
} else {
var q = l < 0.5 ?
l * (1 + s) :
l + s - l * s;
var p = 2 * l - q;
r = hueToRgb(p, q, h + 1/3);
g = hueToRgb(p, q, h);
b = hueToRgb(p, q, h - 1/3);
}
return [~~(r * 255), ~~(g * 255), ~~(b * 255)];
}
function hueToRgb(p, q, t) {
if (t < 0) t += 1;
if (t > 1) t -= 1;
if (t < 1/6) return p + (q - p) * 6 * t;
if (t < 1/2) return q;
if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
return p;
}
function shortenHsl(hue, saturation, lightness) {
var asRgb = hslToRgb(hue, saturation, lightness);
var redAsHex = asRgb[0].toString(16);
var greenAsHex = asRgb[1].toString(16);
var blueAsHex = asRgb[2].toString(16);
return '#' +
((redAsHex.length == 1 ? '0' : '') + redAsHex) +
((greenAsHex.length == 1 ? '0' : '') + greenAsHex) +
((blueAsHex.length == 1 ? '0' : '') + blueAsHex);
}
module.exports = shortenHsl;
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