颜色值rgb与16进制color转换

颜色值之间的转换js代码。

十六进制与RGB转换

//十六进制颜色值的正则表达式
var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
/*RGB颜色转换为16进制*/
String.prototype.colorHex = function(){
    var that = this;
    if(/^(rgb|RGB)/.test(that)){
        var aColor = that.replace(/(?:\(|\)|rgb|RGB)*/g,"").split(",");
        var strHex = "#";
        for(var i=0; i<aColor.length; i++){
            var hex = Number(aColor[i]).toString(16);
            if(hex === "0"){
                hex += hex; 
            }
            strHex += hex;
        }
        if(strHex.length !== 7){
            strHex = that;  
        }
        return strHex;
    }else if(reg.test(that)){
        var aNum = that.replace(/#/,"").split("");
        if(aNum.length === 6){
            return that;    
        }else if(aNum.length === 3){
            var numHex = "#";
            for(var i=0; i<aNum.length; i+=1){
                numHex += (aNum[i]+aNum[i]);
            }
            return numHex;
        }
    }else{
        return that;    
    }
};

//-------------------------------------------------

/*16进制颜色转为RGB格式*/
String.prototype.colorRgb = function(){
    var sColor = this.toLowerCase();
    if(sColor && reg.test(sColor)){
        if(sColor.length === 4){
            var sColorNew = "#";
            for(var i=1; i<4; i+=1){
                sColorNew += sColor.slice(i,i+1).concat(sColor.slice(i,i+1));   
            }
            sColor = sColorNew;
        }
        //处理六位的颜色值
        var sColorChange = [];
        for(var i=1; i<7; i+=2){
            sColorChange.push(parseInt("0x"+sColor.slice(i,i+2)));  
        }
        return "RGB(" + sColorChange.join(",") + ")";
    }else{
        return sColor;  
    }
};

HSL转RGB

/**
 * HSL颜色值转换为RGB. 
 * 换算公式改编自 http://en.wikipedia.org/wiki/HSL_color_space.
 * h, s, 和 l 设定在 [0, 1] 之间
 * 返回的 r, g, 和 b 在 [0, 255]之间
 *
 * @param   Number  h       色相
 * @param   Number  s       饱和度
 * @param   Number  l       亮度
 * @return  Array           RGB色值数值
 */
function hslToRgb(h, s, l){
    var r, g, b;

    if(s == 0){
        r = g = b = l; // achromatic
    }else{
        var hue2rgb = 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;
        }

        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;
        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
}

RGB转HSL

/**
 * RGB 颜色值转换为 HSL.
 * 转换公式参考自 http://en.wikipedia.org/wiki/HSL_color_space.
 * r, g, 和 b 需要在 [0, 255] 范围内
 * 返回的 h, s, 和 l 在 [0, 1] 之间
 *
 * @param   Number  r       红色色值
 * @param   Number  g       绿色色值
 * @param   Number  b       蓝色色值
 * @return  Array           HSL各值数组
 */
function rgbToHsl(r, g, b){
    r /= 255, g /= 255, b /= 255;
    var max = Math.max(r, g, b), min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2;

    if(max == min){
        h = s = 0; // achromatic
    }else{
        var d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
        switch(max){
            case r: h = (g - b) / d + (g < b ? 6 : 0); break;
            case g: h = (b - r) / d + 2; break;
            case b: h = (r - g) / d + 4; break;
        }
        h /= 6;
    }

    return [h, s, l];
}

原文出处：前端开发博客 (http://caibaojian.com/rgb2color.html)