| New file |
| | |
| | | /* |
| | | * @Author: shuishen 1109946754@qq.com |
| | | * @Date: 2022-10-21 16:42:56 |
| | | * @LastEditors: shuishen 1109946754@qq.com |
| | | * @LastEditTime: 2022-10-21 16:43:01 |
| | | * @FilePath: \sd-jg-school-web\src\utils\devicePixelRatio.js |
| | | * @Description: |
| | | * |
| | | * Copyright (c) 2022 by shuishen 1109946754@qq.com, All Rights Reserved. |
| | | */ |
| | | class DevicePixelRatio { |
| | | constructor() { |
| | | // this.flag = false |
| | | } |
| | | |
| | | // 获取系统类型 |
| | | _getSystem () { |
| | | const flag = false |
| | | var agent = navigator.userAgent.toLowerCase() |
| | | // var isMac = /macintosh|mac os x/i.test(navigator.userAgent); |
| | | // if(isMac) { |
| | | // return false; |
| | | // } |
| | | // 现只针对windows处理,其它系统暂无该情况,如有,继续在此添加 |
| | | if (agent.indexOf('windows') >= 0) { |
| | | return true |
| | | } |
| | | } |
| | | |
| | | // 获取页面缩放比例 |
| | | // _getDevicePixelRatio() { |
| | | // let t = this; |
| | | // } |
| | | // 监听方法兼容写法 |
| | | _addHandler (element, type, handler) { |
| | | if (element.addEventListener) { |
| | | element.addEventListener(type, handler, false) |
| | | } else if (element.attachEvent) { |
| | | element.attachEvent('on' + type, handler) |
| | | } else { |
| | | element['on' + type] = handler |
| | | } |
| | | } |
| | | |
| | | // 校正浏览器缩放比例 |
| | | _correct () { |
| | | const t = this |
| | | // 页面devicePixelRatio(设备像素比例)变化后,计算页面body标签zoom修改其大小,来抵消devicePixelRatio带来的变化。 |
| | | document.getElementsByTagName('body')[0].style.zoom = 1 / window.devicePixelRatio |
| | | } |
| | | |
| | | // 监听页面缩放 |
| | | _watch () { |
| | | const t = this |
| | | t._addHandler(window, 'resize', function () { // 注意这个方法是解决全局有两个window.resize |
| | | // 重新校正 |
| | | t._correct() |
| | | }) |
| | | } |
| | | |
| | | // 初始化页面比例 |
| | | init () { |
| | | const t = this |
| | | if (t._getSystem()) { // 判断设备,目前只在windows系统下校正浏览器缩放比例 |
| | | // 初始化页面校正浏览器缩放比例 |
| | | t._correct() |
| | | // 开启监听页面缩放 |
| | | t._watch() |
| | | } |
| | | } |
| | | } |
| | | export default DevicePixelRatio |