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) ];
}   

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，

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};
}

一个hsl|的颜色值，设置在javascript，将立即 所有你需要做的是，然后访问 计算样式值

document.body.style.color = 'hsla(44, 100%, 50%, 0.8)';

console.log(window.getComputedStyle(document.body).color);

// displays: rgba(255, 187, 0, 0.8)

从技术上讲，我想，这甚至不是任何一行代码-这是 自动完成。所以，取决于你的环境，你 也许这样就能逃过一劫。并不是说没有 这里有很多深思熟虑的回复。我不知道你的 目标是。

现在，如果你想从rbg|a转换到hsl|a呢?

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;
}

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);
}