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;(function(win, lib) {
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var doc = win.document;
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var docEl = doc.documentElement;
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var metaEl = doc.querySelector('meta[name="viewport"]');
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var flexibleEl = doc.querySelector('meta[name="flexible"]');
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var dpr = 0;
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var scale = 0;
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var tid;
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var flexible = lib.flexible || (lib.flexible = {});
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if (metaEl) {
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console.warn('将根据已有的meta标签来设置缩放比例');
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var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);
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if (match) {
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scale = parseFloat(match[1]);
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dpr = parseInt(1 / scale);
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}
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} else if (flexibleEl) {
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var content = flexibleEl.getAttribute('content');
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if (content) {
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var initialDpr = content.match(/initial\-dpr=([\d\.]+)/);
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var maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/);
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if (initialDpr) {
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dpr = parseFloat(initialDpr[1]);
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scale = parseFloat((1 / dpr).toFixed(2));
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}
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if (maximumDpr) {
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dpr = parseFloat(maximumDpr[1]);
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scale = parseFloat((1 / dpr).toFixed(2));
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}
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}
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}
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if (!dpr && !scale) {
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var isAndroid = win.navigator.appVersion.match(/android/gi);
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var isIPhone = win.navigator.appVersion.match(/iphone/gi);
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var devicePixelRatio = win.devicePixelRatio;
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if (isIPhone) {
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// iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
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if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {
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dpr = 3;
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} else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)){
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dpr = 2;
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} else {
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dpr = 1;
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}
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} else {
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// 其他设备下，仍旧使用1倍的方案
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dpr = 1;
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}
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scale = 1 / dpr;
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}
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docEl.setAttribute('data-dpr', dpr);
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if (!metaEl) {
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metaEl = doc.createElement('meta');
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metaEl.setAttribute('name', 'viewport');
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metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');
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if (docEl.firstElementChild) {
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docEl.firstElementChild.appendChild(metaEl);
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} else {
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var wrap = doc.createElement('div');
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wrap.appendChild(metaEl);
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doc.write(wrap.innerHTML);
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}
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}
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function refreshRem(){
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var width = docEl.getBoundingClientRect().width;
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if (width / dpr > 1920) {
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width = 1920 * dpr;
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}else if (width / dpr < 1920 && width / dpr > 900) {
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width = width * dpr;
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}
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var rem = width / 10;
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docEl.style.fontSize = rem + 'px';
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flexible.rem = win.rem = rem;
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}
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win.addEventListener('resize', function() {
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clearTimeout(tid);
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tid = setTimeout(refreshRem, 300);
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}, false);
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win.addEventListener('pageshow', function(e) {
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if (e.persisted) {
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clearTimeout(tid);
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tid = setTimeout(refreshRem, 300);
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}
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}, false);
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if (doc.readyState === 'complete') {
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doc.body.style.fontSize = 12 * dpr + 'px';
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} else {
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doc.addEventListener('DOMContentLoaded', function(e) {
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doc.body.style.fontSize = 12 * dpr + 'px';
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}, false);
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}
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refreshRem();
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flexible.dpr = win.dpr = dpr;
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flexible.refreshRem = refreshRem;
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flexible.rem2px = function(d) {
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var val = parseFloat(d) * this.rem;
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if (typeof d === 'string' && d.match(/rem$/)) {
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val += 'px';
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}
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return val;
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}
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flexible.px2rem = function(d) {
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var val = parseFloat(d) / this.rem;
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if (typeof d === 'string' && d.match(/px$/)) {
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val += 'rem';
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}
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return val;
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}
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})(window, window['lib'] || (window['lib'] = {}));
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