我正在寻找一个算法之间的HSL颜色转换为RGB。
在我看来，HSL不是很广泛地使用，所以我没有太多的运气寻找一个转换器。
当前回答
简短而精确- JS
使用这个JS代码(更多:rgb2hsl, hsv2rgb rgb2hsv和hsl2hsv) - php版本在这里
// input: h as an angle in [0,360] and s,l 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)];
}
// 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(''); console.log(`hsl: (30,0.2,0.3) --> rgb: (${hsl2rgb(30,0.2,0.3)}) --> hex: ${rgb2hex(...hsl2rgb(30,0.2,0.3))}`); // --------------- // 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>
以下是我在wiki +错误分析中发现并精确描述的公式，
其他回答
当你需要RGB到HSV，反之亦然:
function rgbToHsv(r, g, b)
{
r /= 255, g /= 255, b /= 255;
var min = Math.min(r, g, b),
max = Math.max(r, g, b),
delta = max - min,
h = 0, s = 0, v = max;
if (min != max)
{
s = (delta / max);
switch (max)
{
case r: h = (g - b) / delta + (g < b ? 6 : 0); break;
case g: h = (b - r) / delta + 2; break;
case b: h = (r - g) / delta + 4; break;
}
h /= 6;
}
return [h, s, v];
}
function hsvToRgb(h, s, v)
{
var step = h / (1 / 6),
pos = step - Math.floor(step), // the hue position within the current step
m = (Math.floor(step) % 2) ? (1 - pos) * v : pos * v, // mix color value adjusted to the brightness(v)
max = 1 * v,
min = (1 - s) * v,
med = m + ((1 - s) * (v - m)),
r, g, b;
switch (Math.floor(step))
{
case 0:
r = max;
g = med;
b = min;
break;
case 1:
r = med;
g = max;
b = min;
break;
case 2:
r = min;
g = max;
b = med;
break;
case 3:
r = min;
g = med;
b = max;
break;
case 4:
r = med;
g = min;
b = max;
break;
case 5:
r = max;
g = min;
b = med;
break;
}
return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
}
H, S, L在[0,1]范围内:
ConvertHslToRgb: function (iHsl)
{
var min, sv, sextant, fract, vsf;
var v = (iHsl.l <= 0.5) ? (iHsl.l * (1 + iHsl.s)) : (iHsl.l + iHsl.s - iHsl.l * iHsl.s);
if (v === 0)
return { Red: 0, Green: 0, Blue: 0 };
min = 2 * iHsl.l - v;
sv = (v - min) / v;
var h = (6 * iHsl.h) % 6;
sextant = Math.floor(h);
fract = h - sextant;
vsf = v * sv * fract;
switch (sextant)
{
case 0: return { r: v, g: min + vsf, b: min };
case 1: return { r: v - vsf, g: v, b: min };
case 2: return { r: min, g: v, b: min + vsf };
case 3: return { r: min, g: v - vsf, b: v };
case 4: return { r: min + vsf, g: min, b: v };
case 5: return { r: v, g: min, b: v - vsf };
}
}
Unity3D c#代码来自Mohsen的回答。
以下是Mohsen用c#编写的针对Unity3D的回答。它改编自上面Alec Thilenius给出的c#答案。
using UnityEngine;
using System.Collections;
public class ColorTools {
/// <summary>
/// Converts an HSL color value to RGB.
/// Input: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )**strong text**
/// Output: Color ( R: [0.0, 1.0], G: [0.0, 1.0], B: [0.0, 1.0], A: [0.0, 1.0] )
/// </summary>
/// <param name="hsl">Vector4 defining X = h, Y = s, Z = l, W = a. Ranges [0, 1.0]</param>
/// <returns>RGBA Color. Ranges [0.0, 1.0]</returns>
public static Color HslToRgba(Vector4 hsl)
{
float r, g, b;
if (hsl.y == 0.0f)
r = g = b = hsl.z;
else
{
var q = hsl.z < 0.5f ? hsl.z * (1.0f + hsl.y) : hsl.z + hsl.y - hsl.z * hsl.y;
var p = 2.0f * hsl.z - q;
r = HueToRgb(p, q, hsl.x + 1.0f / 3.0f);
g = HueToRgb(p, q, hsl.x);
b = HueToRgb(p, q, hsl.x - 1.0f / 3.0f);
}
return new Color(r, g, b, hsl.w);
}
// Helper for HslToRgba
private static float HueToRgb(float p, float q, float t)
{
if (t < 0.0f) t += 1.0f;
if (t > 1.0f) t -= 1.0f;
if (t < 1.0f / 6.0f) return p + (q - p) * 6.0f * t;
if (t < 1.0f / 2.0f) return q;
if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6.0f;
return p;
}
/// <summary>
/// Converts an RGB color value to HSL.
/// Input: Color ( R: [0.0, 1.0], G: [0.0, 1.0], B: [0.0, 1.0], A: [0.0, 1.0] )
/// Output: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )
/// </summary>
/// <param name="rgba"></param>
/// <returns></returns>
public static Vector4 RgbaToHsl(Color rgba)
{
float max = (rgba.r > rgba.g && rgba.r > rgba.b) ? rgba.r :
(rgba.g > rgba.b) ? rgba.g : rgba.b;
float min = (rgba.r < rgba.g && rgba.r < rgba.b) ? rgba.r :
(rgba.g < rgba.b) ? rgba.g : rgba.b;
float h, s, l;
h = s = l = (max + min) / 2.0f;
if (max == min)
h = s = 0.0f;
else
{
float d = max - min;
s = (l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (rgba.r > rgba.g && rgba.r > rgba.b)
h = (rgba.g - rgba.b) / d + (rgba.g < rgba.b ? 6.0f : 0.0f);
else if (rgba.g > rgba.b)
h = (rgba.b - rgba.r) / d + 2.0f;
else
h = (rgba.r - rgba.g) / d + 4.0f;
h /= 6.0f;
}
return new Vector4(h, s, l, rgba.a);
}
}
Mohsen代码的Java实现
注意，所有整数都声明为浮点数(即1f)，必须是浮点数，否则您将选择灰色。
HSL到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 h The hue
* @param s The saturation
* @param l The lightness
* @return int array, the RGB representation
*/
public static int[] hslToRgb(float h, float s, float l){
float r, g, b;
if (s == 0f) {
r = g = b = l; // achromatic
} else {
float q = l < 0.5f ? l * (1 + s) : l + s - l * s;
float p = 2 * l - q;
r = hueToRgb(p, q, h + 1f/3f);
g = hueToRgb(p, q, h);
b = hueToRgb(p, q, h - 1f/3f);
}
int[] rgb = {to255(r), to255(g), to255(b)};
return rgb;
}
public static int to255(float v) { return (int)Math.min(255,256*v); }
/** Helper method that converts hue to rgb */
public static float hueToRgb(float p, float q, float t) {
if (t < 0f)
t += 1f;
if (t > 1f)
t -= 1f;
if (t < 1f/6f)
return p + (q - p) * 6f * t;
if (t < 1f/2f)
return q;
if (t < 2f/3f)
return p + (q - p) * (2f/3f - t) * 6f;
return p;
}
RGB到HSL
/**
* Converts an RGB color value to HSL. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes pR, pG, and bpBare contained in the set [0, 255] and
* returns h, s, and l in the set [0, 1].
*
* @param pR The red color value
* @param pG The green color value
* @param pB The blue color value
* @return float array, the HSL representation
*/
public static float[] rgbToHsl(int pR, int pG, int pB) {
float r = pR / 255f;
float g = pG / 255f;
float b = pB / 255f;
float max = (r > g && r > b) ? r : (g > b) ? g : b;
float min = (r < g && r < b) ? r : (g < b) ? g : b;
float h, s, l;
l = (max + min) / 2.0f;
if (max == min) {
h = s = 0.0f;
} else {
float d = max - min;
s = (l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (r > g && r > b)
h = (g - b) / d + (g < b ? 6.0f : 0.0f);
else if (g > b)
h = (b - r) / d + 2.0f;
else
h = (r - g) / d + 4.0f;
h /= 6.0f;
}
float[] hsl = {h, s, l};
return hsl;
}
如果你正在寻找一些完全符合HSL和RGB的CSS语义的东西，你可以使用css3规范中指定的算法，它如下:
HOW TO RETURN hsl.to.rgb(h, s, l):
SELECT:
l<=0.5: PUT l*(s+1) IN m2
ELSE: PUT l+s-l*s IN m2
PUT l*2-m2 IN m1
PUT hue.to.rgb(m1, m2, h+1/3) IN r
PUT hue.to.rgb(m1, m2, h ) IN g
PUT hue.to.rgb(m1, m2, h-1/3) IN b
RETURN (r, g, b)
HOW TO RETURN hue.to.rgb(m1, m2, h):
IF h<0: PUT h+1 IN h
IF h>1: PUT h-1 IN h
IF h*6<1: RETURN m1+(m2-m1)*h*6
IF h*2<1: RETURN m2
IF h*3<2: RETURN m1+(m2-m1)*(2/3-h)*6
RETURN m1
我相信这是这里其他一些答案的来源。
