js自动缩放页面，html自动缩放页面，大屏自动缩放页面，数字看板自动缩放页面，大数据看板自动缩放页面

由纯JS实现

html代码

html 复制代码

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport"
        content="width=device-width,initial-scale=1.0,maximum-scale=1.0,minimum-scale=1.0,user-scalable=no">

    <title>缩放</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            overflow: hidden;
            color: rgb(0, 0, 0);
            background-color: #1d2553;
        }
        .main {
            width: 1920px;
            height: 1080px;
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            transform-origin: left top;
            background-color: beige;
        } 
        .main img{
            width: 600px;
            height: auto;
            max-width: 100%;
            max-height: 100%;
        }
    </style>
</head>

<body> 
        <div class="main" id="main">
            <h1>缩放</h1>
            <img src="./img/Mercedes_Logo_19.jpg" alt="">
        </div> 
    <script type="module">
        import useDraw from '../js/useDraw.js';
        console.log(useDraw);
        useDraw(document.getElementById('main'));
    </script>
</body>

</html>

js代码

useDraw.js

javascript 复制代码

const useDraw = (appRef) => {
    // * 指向最外层容器
    // let appRef;
    // * 定时函数
    let timer;
    // * 默认缩放值
    const scale = {
        width: '1',
        height: '1',
    }
    // * 设计稿尺寸（px）
    const baseWidth = 1920
    const baseHeight = 1080
    // * 需保持的比例（默认1.77778）
    const baseProportion = parseFloat((baseWidth / baseHeight).toFixed(5))
    const calcRate = () => {
        // 当前宽高比
        const currentRate = parseFloat((window.innerWidth / window.innerHeight).toFixed(5))
        if (appRef) {
            if (currentRate > baseProportion) {
                // 表示更宽
                scale.width = ((window.innerHeight * baseProportion) / baseWidth).toFixed(5)
                scale.height = (window.innerHeight / baseHeight).toFixed(5)
                appRef.style.transform = `scale(${scale.width}, ${scale.height}) translate(-50%, -50%)`
            } else {
                // 表示更高
                scale.height = ((window.innerWidth / baseProportion) / baseHeight).toFixed(5)
                scale.width = (window.innerWidth / baseWidth).toFixed(5)
                appRef.style.transform = `scale(${scale.width}, ${scale.height}) translate(-50%, -50%)`
            }
        }
    }
    calcRate()
    const resize = () => {
        clearTimeout(timer)
        timer = setTimeout(() => {
            calcRate()
        }, 200)
    }

    window.addEventListener('resize', resize)

    // 改变窗口大小重新绘制
    const unWindowDraw = () => {
        window.removeEventListener('resize', resize)
    }
}
export default useDraw;