对于所有说Garry Tan解决方案转换不正确从RGB到HSL和回来。这是因为他在代码中遗漏了数字的一部分。 我纠正了他的代码(javascript)。 对不起，俄语的链接，但在英语缺席- HSL-wiki

function toHsl(r, g, b)
{
    r /= 255.0;
    g /= 255.0;
    b /= 255.0;
    var max = Math.max(r, g, b);
    var min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2.0;

    if(max == min)
    {
        h = s = 0; 
    }
    else
    {
        var d = max - min;
        s = (l > 0.5 ? d / (2.0 - max - min) : d / (max + min));

        if(max == r && g >= b)
        {
            h = 1.0472 * (g - b) / d ;
        }
        else if(max == r && g < b)
        {
            h = 1.0472 * (g - b) / d + 6.2832;
        }
        else if(max == g)
        {
            h = 1.0472 * (b - r) / d + 2.0944;
        }
        else if(max == b)
        {
            h = 1.0472 * (r - g) / d + 4.1888;
        }
    }
    return {
        str: 'hsl(' + parseInt(h / 6.2832 * 360.0 + 0.5) + ',' + parseInt(s * 100.0 + 0.5) + '%,' + parseInt(l * 100.0 + 0.5) + '%)',
        obj: { h: parseInt(h / 6.2832 * 360.0 + 0.5), s: parseInt(s * 100.0 + 0.5), l: parseInt(l * 100.0 + 0.5) }
    };
};

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。

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 };
    }
}

下面是GLSL中快速、超级简单、无分支的版本:

vec3 hsl2rgb( vec3 c ) {
    vec3 rgb = clamp(abs(mod(c.x*6.0 + vec3(0.0, 4.0, 2.0), 6.0)-3.0)-1.0, 0.0, 1.0);
    return c.z + c.y * (rgb-0.5)*(1.0-abs(2.0*c.z-1.0));
}

没有比这更短的了~

原始概念验证的链接:https://www.shadertoy.com/view/XljGzV

(免责声明:不是我的代码!)

Chris的c#代码的Php实现

也是从这里，这很好地解释了它的数学原理。

这基本上是一堆转换HSL(色相饱和度亮度)的函数

在PHP 5.6.15上测试并使用

TL;DR:完整的代码可以在Pastebin上找到。

##Hex to HSL 输入:十六进制颜色，格式:[#]0f4或[#]00ff44(磅号可选) 输出:HSL的程度，百分比，百分比

/**
* Input: hex color
* Output: hsl(in ranges from 0-1)
* 
* Takes the hex, converts it to RGB, and sends
* it to RGBToHsl.  Returns the output.
* 
*/
function hexToHsl($hex) {
    $r = "";
    $g = "";
    $b = "";

    $hex = str_replace('#', '', $hex);
    
    if (strlen($hex) == 3) {
        $r = substr($hex, 0, 1);
        $r = $r . $r;
        $g = substr($hex, 1, 1);
        $g = $g . $g;
        $b = substr($hex, 2, 1);
        $b = $b . $b;
    } elseif (strlen($hex) == 6) {
        $r = substr($hex, 0, 2);
        $g = substr($hex, 2, 2);
        $b = substr($hex, 4, 2);
    } else {
        return false;
    }

    $r = hexdec($r);
    $g = hexdec($g);
    $b = hexdec($b);

    $hsl =  rgbToHsl($r,$g,$b);
    return $hsl;
}

RGB到HSL

输入:RGB，范围0-255 输出:HSL的程度，百分比，百分比。

/**
* 
*Credits:
* https://stackoverflow.com/questions/4793729/rgb-to-hsl-and-back-calculation-problems
* http://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/
*
* Called by hexToHsl by default.
*
* Converts an RGB color value to HSL. Conversion formula
* adapted from http://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/.
* Assumes r, g, and b are contained in the range [0 - 255] and
* returns h, s, and l in the format Degrees, Percent, Percent.
*
* @param   Number  r       The red color value
* @param   Number  g       The green color value
* @param   Number  b       The blue color value
* @return  Array           The HSL representation
*/
function rgbToHsl($r, $g, $b){  
    //For the calculation, rgb needs to be in the range from 0 to 1. To convert, divide by 255 (ff). 
    $r /= 255;
    $g /= 255;
    $b /= 255;
    
    $myMax = max($r, $g, $b);
    $myMin = min($r, $g, $b);
    
    $maxAdd = ($myMax + $myMin);
    $maxSub = ($myMax - $myMin);
    
    //luminence is (max + min)/2
    $h = 0;
    $s = 0;
    $l = ($maxAdd / 2.0);
    
    //if all the numbers are equal, there is no saturation (greyscale).
    if($myMin != $myMax){
        if ($l < 0.5) {
            $s = ($maxSub / $maxAdd);
        } else {
            $s = (2.0 - $myMax - $myMin); //note order of opperations - can't use $maxSub here
            $s = ($maxSub / $s);
        }
        
        //find hue
        switch($myMax){
            case $r: 
                $h = ($g - $b);
                $h = ($h / $maxSub);
                break;
            case $g: 
                $h = ($b - $r); 
                $h = ($h / $maxSub);
                $h = ($h + 2.0);
                break;
            case $b: 
                $h = ($r - $g);
                $h = ($h / $maxSub); 
                $h = ($h + 4.0);
                break;
        } 
    }
    
    $hsl = hslToDegPercPerc($h, $s, $l);
    return $hsl;
}

##HSL(0-1范围)到程度，百分比，百分比格式

对于数学计算，HSL在0-1范围内更容易处理，但对于人类可读性而言，在Degrees, Percent, Percent中更容易处理。该函数接受范围为0-1的HSL，并返回以度、百分比、百分比为单位的HSL。

/**
* Input: HSL in ranges 0-1.
* Output: HSL in format Deg, Perc, Perc.
* 
* Note: rgbToHsl calls this function by default.
* 
* Multiplies $h by 60, and $s and $l by 100.
*/
function hslToDegPercPerc($h, $s, $l) {
    //convert h to degrees
    $h *= 60;
    
    if ($h < 0) {
        $h += 360;
    }
    
    //convert s and l to percentage
    $s *= 100;
    $l *= 100;
    
    $hsl['h'] = $h;
    $hsl['s'] = $s;
    $hsl['l'] = $l;
    return $hsl;
}

##HSL(度，百分比，百分比格式)到范围为0-1的HSL

该函数将格式为Degrees, Percent, Percent的HSL转换为0-1的范围，以便于计算。

/**
* Input: HSL in format Deg, Perc, Perc
* Output: An array containing HSL in ranges 0-1
* 
* Divides $h by 60, and $s and $l by 100.
* 
* hslToRgb calls this by default.
*/
function degPercPercToHsl($h, $s, $l) { 
    //convert h, s, and l back to the 0-1 range
    
    //convert the hue's 360 degrees in a circle to 1
    $h /= 360;
    
    //convert the saturation and lightness to the 0-1 
    //range by multiplying by 100
    $s /= 100;
    $l /= 100;
    
    $hsl['h'] =  $h;
    $hsl['s'] = $s;
    $hsl['l'] = $l;
    
    return $hsl;
}

##HSL到RGB

输入:格式为度，百分比，百分比的HSL 输出:RGB，格式为255,255,255。

/**
* Converts an HSL color value to RGB. Conversion formula
* adapted from http://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/.
* Assumes h, s, and l are in the format Degrees,
* Percent, Percent, and returns r, g, and b in 
* the range [0 - 255].
*
* Called by hslToHex by default.
*
* Calls: 
*   degPercPercToHsl
*   hueToRgb
*
* @param   Number  h       The hue value
* @param   Number  s       The saturation level
* @param   Number  l       The luminence
* @return  Array           The RGB representation
*/
function hslToRgb($h, $s, $l){
    $hsl = degPercPercToHsl($h, $s, $l);
    $h = $hsl['h'];
    $s = $hsl['s'];
    $l = $hsl['l'];

    //If there's no saturation, the color is a greyscale,
    //so all three RGB values can be set to the lightness.
    //(Hue doesn't matter, because it's grey, not color)
    if ($s == 0) {
        $r = $l * 255;
        $g = $l * 255;
        $b = $l * 255;
    }
    else {
        //calculate some temperary variables to make the 
        //calculation eaisier.
        if ($l < 0.5) {
            $temp2 = $l * (1 + $s);
        } else {
            $temp2 = ($l + $s) - ($s * $l);
        }
        $temp1 = 2 * $l - $temp2;
        
        //run the calculated vars through hueToRgb to
        //calculate the RGB value.  Note that for the Red
        //value, we add a third (120 degrees), to adjust 
        //the hue to the correct section of the circle for
        //red.  Simalarly, for blue, we subtract 1/3.
        $r = 255 * hueToRgb($temp1, $temp2, $h + (1 / 3));
        $g = 255 * hueToRgb($temp1, $temp2, $h);
        $b = 255 * hueToRgb($temp1, $temp2, $h - (1 / 3));
    }
        
    $rgb['r'] = $r;
    $rgb['g'] = $g;
    $rgb['b'] = $b;

    return $rgb;
}

###色调到RGB

hslToRgb调用此函数将色调转换为单独的RGB值。

/**
* Converts an HSL hue to it's RGB value.  
*
* Input: $temp1 and $temp2 - temperary vars based on 
* whether the lumanence is less than 0.5, and 
* calculated using the saturation and luminence
* values.
*  $hue - the hue (to be converted to an RGB 
* value)  For red, add 1/3 to the hue, green 
* leave it alone, and blue you subtract 1/3 
* from the hue.
*
* Output: One RGB value.
*
* Thanks to Easy RGB for this function (Hue_2_RGB).
* http://www.easyrgb.com/index.php?X=MATH&$h=19#text19
*
*/
function hueToRgb($temp1, $temp2, $hue) {
    if ($hue < 0) { 
        $hue += 1;
    }
    if ($hue > 1) {
        $hue -= 1;
    }
    
    if ((6 * $hue) < 1 ) {
        return ($temp1 + ($temp2 - $temp1) * 6 * $hue);
    } elseif ((2 * $hue) < 1 ) {
        return $temp2;
    } elseif ((3 * $hue) < 2 ) {
        return ($temp1 + ($temp2 - $temp1) * ((2 / 3) - $hue) * 6);
    }
    return $temp1;
}

##HSL到Hex

输入:HSL格式的度，百分比，百分比 输出:十六进制格式00ff22(没有磅号)。

转换为RGB，然后分别转换为十六进制。

/**
* Converts HSL to Hex by converting it to 
* RGB, then converting that to hex.
* 
* string hslToHex($h, $s, $l[, $prependPound = true]
* 
* $h is the Degrees value of the Hue
* $s is the Percentage value of the Saturation
* $l is the Percentage value of the Lightness
* $prependPound is a bool, whether you want a pound 
*  sign prepended. (optional - default=true)
*
* Calls: 
*   hslToRgb
*
* Output: Hex in the format: #00ff88 (with 
* pound sign).  Rounded to the nearest whole
* number.
*/
function hslToHex($h, $s, $l, $prependPound = true) {
    //convert hsl to rgb
    $rgb = hslToRgb($h,$s,$l);

    //convert rgb to hex
    $hexR = $rgb['r'];
    $hexG = $rgb['g'];
    $hexB = $rgb['b'];
    
    //round to the nearest whole number
    $hexR = round($hexR);
    $hexG = round($hexG);
    $hexB = round($hexB);
    
    //convert to hex
    $hexR = dechex($hexR);
    $hexG = dechex($hexG);
    $hexB = dechex($hexB);
    
    //check for a non-two string length
    //if it's 1, we can just prepend a
    //0, but if it is anything else non-2,
    //it must return false, as we don't 
    //know what format it is in.
    if (strlen($hexR) != 2) {
        if (strlen($hexR) == 1) {
            //probably in format #0f4, etc.
            $hexR = "0" . $hexR;
        } else {
            //unknown format
            return false;
        }
    }
    if (strlen($hexG) != 2) {
        if (strlen($hexG) == 1) {
            $hexG = "0" . $hexG;
        } else {
            return false;
        }
    }
    if (strlen($hexB) != 2) {
        if (strlen($hexB) == 1) {
            $hexB = "0" . $hexB;
        } else {
            return false;
        }
    }
    
    //if prependPound is set, will prepend a
    //# sign to the beginning of the hex code.
    //(default = true)
    $hex = "";
    if ($prependPound) {
        $hex = "#";
    }
    
    $hex = $hex . $hexR . $hexG . $hexB;
    
    return $hex;
}

来自Mohsen回答的c#代码。

下面是Mohsen用c#编写的答案代码，如果有人想要的话。注意:Color是自定义类，Vector4来自OpenTK。两者都很容易被你选择的其他东西取代。

Hsl到Rgba

/// <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] )
/// Output: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// </summary>
/// <param name="hsl">Vector4 defining X = h, Y = s, Z = l, W = a. Ranges [0, 1.0]</param>
/// <returns>RGBA Color. Ranges [0, 255]</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((int)(r * 255), (int)(g * 255), (int)(b * 255), (int)(hsl.W * 255));
}

// 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;
}

Rgba到Hsl

/// <summary>
/// Converts an RGB color value to HSL.
/// Input: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// 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 r = rgba.R / 255.0f;
    float g = rgba.G / 255.0f;
    float b = rgba.B / 255.0f;

    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;
    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 (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;
    }

    return new Vector4(h, s, l, rgba.A / 255.0f);
}