我从Brandon Mathis的HSL Picker源代码中得到了这个。

它最初是用CoffeeScript编写的。我使用在线转换器将其转换为JavaScript，并拿出验证用户输入是否为有效RGB值的机制。这个答案适用于我的用例，因为我发现这篇文章上投票最多的答案不能产生有效的HSL值。

注意，它返回一个hsla值，表示不透明/透明。0是完全透明的，1是完全不透明的。

function rgbToHsl(rgb) {
  var a, add, b, diff, g, h, hue, l, lum, max, min, r, s, sat;
  r = parseFloat(rgb[0]) / 255;
  g = parseFloat(rgb[1]) / 255;
  b = parseFloat(rgb[2]) / 255;
  max = Math.max(r, g, b);
  min = Math.min(r, g, b);
  diff = max - min;
  add = max + min;
  hue = min === max ? 0 : r === max ? ((60 * (g - b) / diff) + 360) % 360 : g === max ? (60 * (b - r) / diff) + 120 : (60 * (r - g) / diff) + 240;
  lum = 0.5 * add;
  sat = lum === 0 ? 0 : lum === 1 ? 1 : lum <= 0.5 ? diff / add : diff / (2 - add);
  h = Math.round(hue);
  s = Math.round(sat * 100);
  l = Math.round(lum * 100);
  a = parseFloat(rgb[3]) || 1;
  return [h, s, l, a];
}

PHP -简短但精确

在这里，我将我的JS答案(数学细节在那里)重写为PHP -你可以在这里运行它

function hsl2rgb($h,$s,$l) 
{
  $a = $s * min($l, 1-$l);
  $k = function($n,$h) { return ($n+$h/30)%12;};
  $f = function($n) use ($h,$s,$l,$a,$k) { 
      return $l - $a * max( min($k($n,$h)-3, 9-$k($n,$h), 1),-1);
  };
  return [ $f(0), $f(8), $f(4) ];
}   

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)];
}

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};
}

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);
}

@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 */