Java版本:

/*
Converts color from HSL/A format to RGB/A format
0 <= h <= 360
0 <= s, l, a <= 1
Based on: https://en.wikipedia.org/wiki/HSL_and_HSV#:~:text=%5Bedit%5D-,HSL%20to%20RGB%5Bedit%5D,-Given%20a%20color
 */
public RGB toRGB(double h, double s, double l, Double a) {
    double c = (1 - Math.abs(2 * l - 1)) * s;
    double x = c * (1 - Math.abs((h / 60) % 2 - 1));
    double m = l - c / 2;
    int[] RGBTag = Arrays.stream(getRGBTag(c, x)).mapToInt(e -> (int)Math.round((e + m) * 255)).toArray();
    return RGB(RGBTag[0], RGBTag[1], RGBTag[2], a);

}

private double[] getRGBTag(double c, double x) {
    if (h < 60) {
        return new double[] {c, x, 0};
    } else if (h < 120) {
        return new double[] {x, c, 0};
    } else if (h < 180) {
        return new double[] {0, c, x};
    } else if (h < 240) {
        return new double[] {0, x, c};
    } else if (h < 300) {
        return new double[] {x, 0, c};
    }
    return new double[] {c, 0, x};
}

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。

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)];
}

我需要一个非常轻的重量，它不是100%，但它足够接近一些用例。

float3 Hue(float h, float s, float l)
{
    float r = max(cos(h * 2 * UNITY_PI) * 0.5 + 0.5, 0);
    float g = max(cos((h + 0.666666) * 2 * UNITY_PI) * 0.5 + 0.5, 0);
    float b = max(cos((h + 0.333333) * 2 * UNITY_PI) * 0.5 + 0.5, 0);
    float gray = 0.2989 * r + 0.5870 * g + 0.1140 * b;
    return lerp(gray, float3(r, g, b), s) * smoothstep(0, 0.5, l) + 1 * smoothstep(0.5, 1, l);
}

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，

c++实现，性能可能比@Mohsen代码更好。它使用[0-6]范围的色调，避免除和乘6。S和L的范围为[0,1]

void fromRGBtoHSL(float rgb[], float hsl[])
{
     const float maxRGB = max(rgb[0], max(rgb[1], rgb[2]));
     const float minRGB = min(rgb[0], min(rgb[1], rgb[2]));
     const float delta2 = maxRGB + minRGB;
     hsl[2] = delta2 * 0.5f;

     const float delta = maxRGB - minRGB;
     if (delta < FLT_MIN)
         hsl[0] = hsl[1] = 0.0f;
     else
     {
         hsl[1] = delta / (hsl[2] > 0.5f ? 2.0f - delta2 : delta2);
         if (rgb[0] >= maxRGB)
         {
             hsl[0] = (rgb[1] - rgb[2]) / delta;
             if (hsl[0] < 0.0f)
                 hsl[0] += 6.0f;
         }
         else if (rgb[1] >= maxRGB)
             hsl[0] = 2.0f + (rgb[2] - rgb[0]) / delta;
         else
             hsl[0] = 4.0f + (rgb[0] - rgb[1]) / delta;
     }
}

void fromHSLtoRGB(const float hsl[], float rgb[])
{
    if(hsl[1] < FLT_MIN)
        rgb[0] = rgb[1] = rgb[2] = hsl[2];
    else if(hsl[2] < FLT_MIN)
        rgb[0] = rgb[1] = rgb[2] = 0.0f;
    else
    {
        const float q = hsl[2] < 0.5f ? hsl[2] * (1.0f + hsl[1]) : hsl[2] + hsl[1] - hsl[2] * hsl[1];
        const float p = 2.0f * hsl[2] - q;
        float t[] = {hsl[0] + 2.0f, hsl[0], hsl[0] - 2.0f};

        for(int i=0; i<3; ++i)
        {
            if(t[i] < 0.0f)
                t[i] += 6.0f;
            else if(t[i] > 6.0f)
                t[i] -= 6.0f;

            if(t[i] < 1.0f)
                rgb[i] = p + (q - p) * t[i];
            else if(t[i] < 3.0f)
                rgb[i] = q;
            else if(t[i] < 4.0f)
                rgb[i] = p + (q - p) * (4.0f - t[i]);
            else
                rgb[i] = p;
          }
      }
}