convert Hsl to rgb and hex
I need a color converter to convert from hsl to rgb and hex value. I am going to do similar like this. I am using jquery and jquery ui range slider for this. Here is my code:
$(function() {
$( "#hsl_hue_range" ).slider({
min: 0,
max: 100,
value: 0,
range: false,
animate:"slow",
orientation: "horizontal",
slide: function( event, ui ) {
var hsl_hue = ui.value;
}
});
});
$(function() {
$( "#hsl_saturation_range" ).slider({
min: 0,
max: 100,
value: 0,
range: false,
animate:"slow",
orientation: "horizontal",
slide: function( event, ui ) {
var hsl_saturation = ui.value;
}
});
});
$(function() {
$( "#hsl_light_range" ).slider({
min: 0,
max: 100,
value: 0,
range: false,
animate:"slow",
orientation: "horizontal",
slide: function( event, ui ) {
var hsl_light = ui.value;
}
});
});
I want the solution like this:
the input to converter can be given by the variables. like hsl_hue hsl_saturation hsl_light.
Is there any way to do this?
if no way, what can I do?
Solution 1:
New approach (inspired by @Kamil-Kiełczewski solution)
Takes degree, percentage, percentage and returns css hex color:
function hslToHex(h, s, l) {
l /= 100;
const a = s * Math.min(l, 1 - l) / 100;
const f = n => {
const k = (n + h / 30) % 12;
const color = l - a * Math.max(Math.min(k - 3, 9 - k, 1), -1);
return Math.round(255 * color).toString(16).padStart(2, '0'); // convert to Hex and prefix "0" if needed
};
return `#${f(0)}${f(8)}${f(4)}`;
}
Example:
hslToHex(360, 100, 50) // "#ff0000" -> red
Original version: (still OK, just longer)
Takes degree, percentage, percentage and returns css hex color:
function hslToHex(h, s, l) {
h /= 360;
s /= 100;
l /= 100;
let r, g, b;
if (s === 0) {
r = g = b = l; // achromatic
} else {
const hue2rgb = (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;
};
const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
const p = 2 * l - q;
r = hue2rgb(p, q, h + 1 / 3);
g = hue2rgb(p, q, h);
b = hue2rgb(p, q, h - 1 / 3);
}
const toHex = x => {
const hex = Math.round(x * 255).toString(16);
return hex.length === 1 ? '0' + hex : hex;
};
return `#${toHex(r)}${toHex(g)}${toHex(b)}`;
}
Example:
hslToHex(360, 100, 50) // "#ff0000" -> red
Solution 2:
Shortest
Try this (wiki, error analysis, more: rgb2hsl, hsv2rgb rgb2hsv and hsl2hsv)
// input: h in [0,360] and s,v in [0,1] - output: r,g,b in [0,1]
function hsl2rgb(h,s,l)
{
let a= s*Math.min(l,1-l);
let f= (n,k=(n+h/30)%12) => l - a*Math.max(Math.min(k-3,9-k,1),-1);
return [f(0),f(8),f(4)];
}
To calc hsl2hex use rgb2hex(...hsl2rgb(30,1,0.5)). To convert string from format e.g. rgb(255, 255, 255) to hex use rgbStrToHex (which handle empty string case) as follows
// oneliner version
let hsl2rgb = (h,s,l, a=s*Math.min(l,1-l), f= (n,k=(n+h/30)%12) => l - a*Math.max(Math.min(k-3,9-k,1),-1)) => [f(0),f(8),f(4)];
// r,g,b are in [0-1], result e.g. #0812fa.
let rgb2hex = (r,g,b) => "#" + [r,g,b].map(x=>Math.round(x*255).toString(16).padStart(2,0) ).join('');
// hexStr e.g #abcdef, result "rgb(171,205,239)"
let hexStr2rgb = (hexStr) => `rgb(${hexStr.substr(1).match(/../g).map(x=>+`0x${x}`)})`;
// rgb - color str e.g."rgb(12,233,43)", result color hex e.g. "#0ce92b"
let rgbStrToHex= rgb=> '#'+rgb.match(/\d+/g).map(x=>(+x).toString(16).padStart(2,0)).join``
console.log(`hsl: (30,0.2,0.3) --> rgb: (${hsl2rgb(30,0.2,0.3)}) --> hex: ${rgb2hex(...hsl2rgb(30,0.2,0.3))}`);
console.log(`rgb: ${hexStr2rgb("#ff647b")} --> hex: ${rgbStrToHex("rgb(255,100, 123)")}`)
// ---------------
// UX
// ---------------
rgb= [0,0,0];
hs= [0,0,0];
let $ = x => document.querySelector(x);
function changeRGB(i,e) {
rgb[i]=e.target.value/255;
hs = rgb2hsl(...rgb);
refresh();
}
function changeHS(i,e) {
hs[i]=e.target.value/(i?255:1);
rgb= hsl2rgb(...hs);
refresh();
}
function refresh() {
rr = rgb.map(x=>x*255|0).join(', ')
hh = rgb2hex(...rgb);
tr = `RGB: ${rr}`
th = `HSL: ${hs.map((x,i)=>i? (x*100).toFixed(2)+'%':x|0).join(', ')}`
thh= `HEX: ${hh}`
$('.box').style.backgroundColor=`rgb(${rr})`;
$('.infoRGB').innerHTML=`${tr}`;
$('.infoHS').innerHTML =`${th}\n${thh}`;
$('#r').value=rgb[0]*255;
$('#g').value=rgb[1]*255;
$('#b').value=rgb[2]*255;
$('#h').value=hs[0];
$('#s').value=hs[1]*255;
$('#l').value=hs[2]*255;
}
function rgb2hsl(r,g,b) {
let a=Math.max(r,g,b), n=a-Math.min(r,g,b), f=(1-Math.abs(a+a-n-1));
let h= n && ((a==r) ? (g-b)/n : ((a==g) ? 2+(b-r)/n : 4+(r-g)/n));
return [60*(h<0?h+6:h), f ? n/f : 0, (a+a-n)/2];
}
refresh();.box {
width: 50px;
height: 50px;
margin: 20px;
}
body {
display: flex;
}<div>
<input id="r" type="range" min="0" max="255" oninput="changeRGB(0,event)">R<br>
<input id="g" type="range" min="0" max="255" oninput="changeRGB(1,event)">G<br>
<input id="b" type="range" min="0" max="255" oninput="changeRGB(2,event)">B<br>
<pre class="infoRGB"></pre>
</div>
<div>
<div class="box hsl"></div>
</div>
<div>
<input id="h" type="range" min="0" max="360" oninput="changeHS(0,event)">H<br>
<input id="s" type="range" min="0" max="255" oninput="changeHS(1,event)">S<br>
<input id="l" type="range" min="0" max="255" oninput="changeHS(2,event)">L<br>
<pre class="infoHS"></pre><br>
</div>Solution 3:
HSL to RGB:
/**
* Converts an HSL color value to RGB. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes h, s, and l are contained in the set [0, 1] and
* returns r, g, and b in the set [0, 255].
*
* @param {number} h The hue
* @param {number} s The saturation
* @param {number} l The lightness
* @return {Array} The RGB representation
*/
function hslToRgb(h, s, l){
var r, g, b;
if(s == 0){
r = g = b = l; // achromatic
}else{
var hue2rgb = function hue2rgb(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;
}
var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
var p = 2 * l - q;
r = hue2rgb(p, q, h + 1/3);
g = hue2rgb(p, q, h);
b = hue2rgb(p, q, h - 1/3);
}
return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
}
You can find more information here - HSL to RGB color conversion