How to ensure that the width and height of the image on the page always maintain a ratio of 16:9-CSS Tutorial-php.cn

How to ensure that the width and height of the image on the page always maintain a ratio of 16:9

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Release： 2018-10-23 16:25:24

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The content of this article is about how to keep the width and height of the picture on the page in a ratio of 16:9. It has a certain reference value. Friends in need can refer to it. I hope it will be helpful to you. .

Goal:
Encountered a requirement to keep the image on the page regardless of how the width changes. The width and height maintain the 16:9 ratio.

Implementation:

Method 1: This is also a more classic method, using padding-bottom to achieve.

<!DOCTYPE html>
<html>
<head>
    <title>固定宽高比16:9</title>
    <style type="text/css">
        *{
            margin: 0px;
            padding: 0px;
         }
        .wrap{
            width:100%;
        }
        /* 16:9宽高比，则设padding-bottom:56.25% */
        /* height: 0px,防止矩形被里面的内容撑出多余的高度*/
        .box{
            width: 100vw; 
            height: 0px; 
            position: relative;
            padding-bottom: 56.25%;
            background: pink;
        }
        /* 如果需要在div里面设置内容*/
        /* 需要设置position：absolute，才能设置内容高度100%和矩形一样 */
        /*.box p{
            width: 100%;
            height: 100%;
            position: absolute;
        }*/
    </style>
</head>
<body>
<div class="wrap">
    <div class="box">
        <p>这是一个16：9的矩形</p>
    </div>
</div>
</body>
</html>

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Method 2: Use vmin to achieve it.

<!DOCTYPE html>
<html>
<head>
    <title>固定宽高比16:9</title>
    <style type="text/css">
        *{
            margin: 0px;
            padding: 0px;
         }
        .wrap{
            width:100%;
        }
        /*vmin：相对于可视窗口的宽度或高度中较小的那个，被均分为100单位的vmin*/
        /*例：当宽度是300，高度是600，那么50vmin则是相对于宽度的50%*/
        .box{
            height: 56.25vmin;
            background: pink;
        }

    </style>
</head>
<body>
<div class="wrap">
    <div class="box">
        <p>这是一个16：9的矩形</p>
    </div>
</div>
</body>
</html>

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Note: If the screen width is larger and the height is smaller, vmax can be used. If you need to switch at will, you can control it through js.

Summary:
Both methods have their own pros and cons. Method one: has good compatibility, the code is relatively long, and it is more difficult to understand. Method 2: The code is concise and easy to understand after clarifying the definition, but the compatibility is relatively poor. But what about compatibility, so what are you afraid of? Hahaha.

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