@Mohsen代码的PHP实现(包括Test!)

很抱歉重新发布这篇文章。但我真的没有看到任何其他实现可以提供我所需的质量。

/**
 * 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 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 $p;
        }
function hslToRgb($h, $s, $l){
    if($s == 0){
        $r = $l;
        $g = $l;
        $b = $l; // achromatic
    }else{
        $q = $l < 0.5 ? $l * (1 + $s) : $l + $s - $l * $s;
        $p = 2 * $l - $q;
        $r = hue2rgb($p, $q, $h + 1/3);
        $g = hue2rgb($p, $q, $h);
        $b = hue2rgb($p, $q, $h - 1/3);
    }

    return array(round($r * 255), round($g * 255), round($b * 255));
}

/* Uncomment to test * /
for ($i=0;$i<360;$i++) {
  $rgb=hslToRgb($i/360, 1, .9);
  echo '<div style="background-color:rgb(' .$rgb[0] . ', ' . $rgb[1] . ', ' . $rgb[2] . ');padding:2px;"></div>';
}
/* End Test */

找到了最简单的方法，蟒蛇来拯救:D

colorsys。Hls_to_rgb (h, l, s) 将颜色从HLS坐标转换为RGB坐标。

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);
}

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。

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;
}