rgb插值

    function gradientColor(startColor,endColor,step){
        startRGB = this.colorRgb(startColor);//转换为rgb数组模式
        startR = startRGB[0];
        startG = startRGB[1];
        startB = startRGB[2];
 
        endRGB = this.colorRgb(endColor);
        endR = endRGB[0];
        endG = endRGB[1];
        endB = endRGB[2];
 
        sR = (endR-startR)/step;//总差值
        sG = (endG-startG)/step;
        sB = (endB-startB)/step;
 
        var colorArr = [];
        for(var i=0;i<step;i++){
            //计算每一步的hex值 
            var hex = this.colorHex('rgb('+parseInt((sR*i+startR))+','+parseInt((sG*i+startG))+','+parseInt((sB*i+startB))+')');
            colorArr.push(hex);
        }
        return colorArr;
    }
 
    // 将hex表示方式转换为rgb表示方式(这里返回rgb数组模式)
    gradientColor.prototype.colorRgb = function(sColor){
        var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
        var sColor = sColor.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 sColorChange;
        }else{
            return sColor;
        }
    };
 
    // 将rgb表示方式转换为hex表示方式
    gradientColor.prototype.colorHex = function(rgb){
        var _this = rgb;
        var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
        if(/^(rgb|RGB)/.test(_this)){
            var aColor = _this.replace(/(?:(|)|rgb|RGB)*/g,"").split(",");
            var strHex = "#";
            for(var i=0; i<aColor.length; i++){
                var hex = Number(aColor[i]).toString(16);
                hex = hex<10 ? 0+''+hex :hex;// 保证每个rgb的值为2位
                if(hex === "0"){
                    hex += hex;
                }
                strHex += hex;
            }
            if(strHex.length !== 7){
                strHex = _this;
            }
            return strHex;
        }else if(reg.test(_this)){
            var aNum = _this.replace(/#/,"").split("");
            if(aNum.length === 6){
                return _this;
            }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 _this;
        }
    }