自动化转化

var fs = require('fs');
var paths = require('path');

var config = {
    px: 12,
    fixNumber: 9,
    type: 'rem',
    cssClass: 'em'
};
var reg = {
    // 数字+px 10px
    px: /\d+px/g,
    // font-size 10px
    fontSize: /font-size.*\d+px/g,
    // number
    num: /[^0-9.]+/g
};
var cssFormate = function (path, px, callback) {
    var file = fs.createReadStream(path);
    var fileContent = [];
    var css = [];
    file.setEncoding('utf8');
    file.on('data', function (chunk) {
        // 直接}来分割块会有问题 无法处理{}嵌套的情况
        //fileContent = chunk.split('}');
        fileContent = cssSplit(chunk);
        cssBlock(px, fileContent, function (emFile) {
            emToFile(path, emFile, callback);
        });
    });
    file.on('end', function () {
    });
};

var cssSplit = function (chunk) {
    var stack = [];
    var stackTmp = [];
    var tmp = '';
    var index = 0;
    var fileContent = chunk.split('{');
    for (var i = 0; i < fileContent.length; i++) {
        if (i < fileContent.length - 1) fileContent[i] += '{';
        if (fileContent[i].indexOf('}') !== -1) {
            var right = fileContent[i].split('}');
            for (var j = 0; j < right.length; j++) {
                if (j < right.length - 1) right[j] += '}';
                stack.push(right[j]);
            }
        } else {
            stack.push(fileContent[i]);
        }
    }
    stack.forEach(function (item) {
        if (item.indexOf('{') !== -1) {
            index++;
        } else if (item.indexOf('}') !== -1) {
            index--;
        }
        tmp += item;
        if (index === 0) {
            stackTmp.push(tmp);
            tmp = '';
        }
    });

    return stackTmp;
};

var pxToem = function (chunk, px) {
    var emChunk = chunk.replace(/[\d\.]+px/g, function () {
        var args = Array.prototype.slice.call(arguments)[0];
        var num = args.split('px')[0];
        // 特殊处理1px的情况
        if(num == 0) return 0;
        return (num / px * 12 < 1) ? ('1px') : (num / px).toFixed(config.fixNumber) + config.type;
    });
    return emChunk;
};

var cssBlock = function (px, cssfile, callback) {
    var emFile = '';
    for (var i = 0; i < cssfile.length; i++) {
        var fontSize = 0;

        //if (cssfile[i].indexOf('{') !== -1) {
        //    cssfile[i] += '}';
        //}
        if (cssfile[i].indexOf('font-size') !== -1) {
            // 先把font-size/14处理
            cssfile[i] = cssfile[i].replace(reg.fontSize, function () {
                var args = Array.prototype.slice.call(arguments)[0];
                fontSize = args.replace(reg.num, '');
                return 'font-size: ' + (fontSize / (px || config.px)) + config.type;
            });
        }
        fontSize = (fontSize && config.type !== 'rem') ? fontSize : (px || config.px);
        emFile += pxToem(cssfile[i], fontSize);
    }
    callback(emFile);
};

var emToFile = function (path, emChunk, callback) {
    fs.writeFile(path, emChunk, 'utf-8', function () {
        console.log(path + '-->px2em success!');
        if (callback) {
            callback();
        }
    });
};

module.exports = cssFormate;

开头添加

 <script>
        (function () {
            var createStyle = function (cssText) {
                var document = window.document;
                var styleTag = document.createElement("style");
                styleTag.setAttribute("type", "text/css");
                styleTag.innerHTML = cssText;
                document.getElementsByTagName("head").item(0).appendChild(styleTag);
            };

            var ua = window.navigator.userAgent;
            var isMobile = ua.match(/(Android|iPhone|iPad)/);
            var width = 320;

            if (isMobile) {
                width = window.innerWidth;
                var height = window.innerHeight;
                createStyle('html { font-size: ' + width * 12 / 320 + 'px; font-family: "Helvetica"; }');
                createStyle('.doc { width: ' + width + 'px; height: ' + height+ 'px; }');
            } else {
                createStyle('html { font-size: ' + width * 12 / 320 + 'px; font-family: "黑体-简", "Helvetica"; } ');
                createStyle('textarea, input { font-family: "黑体-简"; } ');
                createStyle('.doc { width: ' + width + 'px; height: ' + width * 16 / 9 + 'px; }');
            }
        }());
    </script>

  csswatcher = gulp.watch(['./css/editor.css','./css/editor2.css','./css/header.css'], function(event){
    var srcPath = event.path;
    var buildPath = srcPath.substr(0,srcPath.length-4) + "-min.css";
    var cssContent = fs.readFileSync(srcPath, 'utf8');
    fs.writeFileSync(buildPath, cssContent, 'utf8');
    px2em(buildPath);
  });