颜色16进制与rgb之间的相互转换

转自：https://blog.csdn.net/a1056244734/article/details/121593952 并优化部分代码

16进制转rgb

hexToRgb(hexStr){
    //十六进制颜色值的正则表达式
    let reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
    let sColor = hexStr.toLowerCase();
        if (sColor && reg.test(sColor)) {
            if (sColor.length === 4) {
                let sColorNew = "#";
                for (let i = 1; i < 4; i += 1) {
                sColorNew += sColor.slice(i, i + 1).concat(sColor.slice(i, i + 1));
            }
            sColor = sColorNew;
        }
        //处理六位的颜色值f
        let sColorChange = [];
        for (let i = 1; i < 7; i += 2) {
            sColorChange.push(parseInt(`0x${sColor.slice(i, i + 2)}`));
        }
        let rgbText = `rgb(${sColorChange.join(",")})`
        return rgbText;
    } else {
        return sColor;
    }
},


hexToRgb("#0088f0")  //rgb(0,136,240)

rgb转16进制

rgbToHex(rgbStr){
    //十六进制颜色值的正则表达式
    const reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
    if (/^(rgb|RGB)/.test(rgbStr)) {
        const aColor = rgbStr.replace(/(?:\(|\)|rgb|RGB)*/g, "").split(",");
        let strHex = "#";
        for (let i = 0; i < aColor.length; i++) {
            let hex = Number(aColor[i]).toString(16).padStart(2,0);
            if (hex === "0") {
                hex += hex;
            }
            strHex += hex;
        }
        if (strHex.length !== 7) {
            strHex = rgbStr;
        }
        return strHex;
    } else if (reg.test(rgbStr)) {
        const aNum = rgbStr.replace(/#/, "").split("");
        if (aNum.length === 6) {
            return rgbStr;
        } else if (aNum.length === 3) {
            let numHex = "#";
            for (let i = 0; i < aNum.length; i += 1) {
                numHex += (aNum[i] + aNum[i]);
            }
            return numHex;
        }
    } else {
        return rgbStr;
    }
},