当你在3D环境中工作时(webGL, ThreeJS)，你有时需要为网格的不同面创建3个值，基本的一个(主色)，一个浅一点的和一个深一点的:

material.color.set( 0x660000, 0xff0000, 0xff6666 ); // red cube

我们可以从主RBG颜色创建这3个值:255,0,0

function rgbToHex(rgb) { 
  var hex = Number(rgb).toString(16);
  if (hex.length < 2) {
       hex = "0" + hex;
  }
  return hex;
};

function convertToHex(r,g,b) { 

    var fact = 100;  // contrast 
    var code = '0x';

    // main color
    var r_hexa = rgbToHex(r);
    var g_hexa = rgbToHex(g);
    var b_hexa = rgbToHex(b);

    // lighter
    var r_light = rgbToHex(Math.floor(r+((1-(r/255))*fact)));
    var g_light = rgbToHex(Math.floor(g+((1-(g/255))*fact)));
    var b_light = rgbToHex(Math.floor(b+((1-(b/255))*fact)));

    // darker
    var r_dark = rgbToHex(Math.floor(r-((r/255)*(fact*1.5)))); // increase contrast
    var g_dark = rgbToHex(Math.floor(g-((g/255)*(fact*1.5))));
    var b_dark = rgbToHex(Math.floor(b-((b/255)*(fact*1.5))));

    var hexa = code+r_hexa+g_hexa+b_hexa;
    var light = code+r_light+g_light+b_light;
    var dark = code+r_dark+g_dark+b_dark;

    console.log('HEXs -> '+dark+" + "+hexa+" + "+light)

    var colors = [dark, hexa, light]; 
    return colors;

}

在你的ThreeJS代码中简单地写:

var material = new THREE.MeshLambertMaterial();
var c = convertToHex(255,0,0); // red cube needed
material.color.set( Number(c[0]), Number(c[1]), Number(c[2]) );

结果:

//                                 dark      normal     light
convertToHex(255,255,255) HEXs -> 0x696969 + 0xffffff + 0xffffff
convertToHex(255,0,0) HEXs -> 0x690000 + 0xff0000 + 0xff6464
convertToHex(255,127,0) HEXs -> 0x690000 + 0xff0000 + 0xff6464
convertToHex(100,100,100) HEXs -> 0x292929 + 0x646464 + 0xa0a0a0
convertToHex(10,10,10) HEXs -> 0x040404 + 0x0a0a0a + 0x6a6a6a

我发现了这个，因为我认为它非常直截了当，有验证测试和支持alpha值(可选)，这将适合这种情况。

只要注释掉regex行，如果你知道你在做什么，它会快一点。

function hexToRGBA(hex, alpha){
    hex = (""+hex).trim().replace(/#/g,""); //trim and remove any leading # if there (supports number values as well)
    if (!/^(?:[0-9a-fA-F]{3}){1,2}$/.test(hex)) throw ("not a valid hex string"); //Regex Validator
    if (hex.length==3){hex=hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2]} //support short form
    var b_int = parseInt(hex, 16);
    return "rgba("+[
        (b_int >> 16) & 255, //R
        (b_int >> 8) & 255, //G
        b_int & 255, //B
        alpha || 1  //add alpha if is set
    ].join(",")+")";
}

2021年版

你可以简单地使用rgb-十六进制和十六进制-rgb，因为它是经过战斗测试的，有多个选项，在其他解决方案中是不可用的。

我最近正在构建一个颜色选择器&这2个包派上用场。

使用

rgb-hex

import rgbHex from 'rgb-hex';

rgbHex(65, 131, 196);
//=> '4183c4'

rgbHex('rgb(40, 42, 54)');
//=> '282a36'

rgbHex(65, 131, 196, 0.2);
//=> '4183c433'

rgbHex(40, 42, 54, '75%');
//=> '282a36bf'

rgbHex('rgba(40, 42, 54, 75%)');
//=> '282a36bf'

hex-rgb

import hexRgb from 'hex-rgb';

hexRgb('4183c4');
//=> {red: 65, green: 131, blue: 196, alpha: 1}

hexRgb('#4183c4');
//=> {red: 65, green: 131, blue: 196, alpha: 1}

hexRgb('#fff');
//=> {red: 255, green: 255, blue: 255, alpha: 1}

hexRgb('#22222299');
//=> {red: 34, green: 34, blue: 34, alpha: 0.6}

hexRgb('#0006');
//=> {red: 0, green: 0, blue: 0, alpha: 0.4}

hexRgb('#cd2222cc');
//=> {red: 205, green: 34, blue: 34, alpha: 0.8}

hexRgb('#cd2222cc', {format: 'array'});
//=> [205, 34, 34, 0.8]

hexRgb('#cd2222cc', {format: 'css'});
//=> 'rgb(205 34 34 / 80%)'

hexRgb('#000', {format: 'css'});
//=> 'rgb(0 0 0)'

hexRgb('#22222299', {alpha: 1});
//=> {red: 34, green: 34, blue: 34, alpha: 1}

hexRgb('#fff', {alpha: 0.5});
//=> {red: 255, green: 255, blue: 255, alpha: 0.5}

一行功能HEX到RGBA

支持短#fff和长#ffffff格式。 支持alpha通道(不透明)。 不关心是否指定散列，在两种情况下都可以工作。

function hexToRGBA(hex, opacity) {
    return 'rgba(' + (hex = hex.replace('#', '')).match(new RegExp('(.{' + hex.length/3 + '})', 'g')).map(function(l) { return parseInt(hex.length%2 ? l+l : l, 16) }).concat(isFinite(opacity) ? opacity : 1).join(',') + ')';
}

例子:

hexToRGBA('#fff')        ->  rgba(255,255,255,1)  
hexToRGBA('#ffffff')     ->  rgba(255,255,255,1)  
hexToRGBA('#fff', .2)    ->  rgba(255,255,255,0.2)  
hexToRGBA('#ffffff', .2) ->  rgba(255,255,255,0.2)  
hexToRGBA('fff', .2)     ->  rgba(255,255,255,0.2)  
hexToRGBA('ffffff', .2)  ->  rgba(255,255,255,0.2)

hexToRGBA('#ffffff', 0)  ->  rgba(255,255,255,0)
hexToRGBA('#ffffff', .5) ->  rgba(255,255,255,0.5)
hexToRGBA('#ffffff', 1)  ->  rgba(255,255,255,1)

我发现了这个… http://jsfiddle.net/Mottie/xcqpF/1/light/

function rgb2hex(rgb){
    rgb = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?/i);
    return (rgb && rgb.length === 4) ? "#" +
        ("0" + parseInt(rgb[1],10).toString(16)).slice(-2) +
        ("0" + parseInt(rgb[2],10).toString(16)).slice(-2) +
        ("0" + parseInt(rgb[3],10).toString(16)).slice(-2) : '';
}

我正在使用XAML数据，具有十六进制格式的#AARRGGBB (Alpha，红色，绿色，蓝色)。利用上面的答案，以下是我的解决方案:

function hexToRgba(hex) {
    var bigint, r, g, b, a;
    //Remove # character
    var re = /^#?/;
    var aRgb = hex.replace(re, '');
    bigint = parseInt(aRgb, 16);

    //If in #FFF format
    if (aRgb.length == 3) {
        r = (bigint >> 4) & 255;
        g = (bigint >> 2) & 255;
        b = bigint & 255;
        return "rgba(" + r + "," + g + "," + b + ",1)";
    }

    //If in #RRGGBB format
    if (aRgb.length >= 6) {
        r = (bigint >> 16) & 255;
        g = (bigint >> 8) & 255;
        b = bigint & 255;
        var rgb = r + "," + g + "," + b;

        //If in #AARRBBGG format
        if (aRgb.length == 8) {
            a = ((bigint >> 24) & 255) / 255;
            return "rgba(" + rgb + "," + a.toFixed(1) + ")";
        }
    }
    return "rgba(" + rgb + ",1)";
}

http://jsfiddle.net/kvLyscs3/