如何用纯 CSS 创作一个货车 loader

骑猪看日落 2022-04-08 08:41 316阅读 0赞

![1446586357-5b70ceb1d54c1_articlex.gif][]

## 效果预览 ##

[在线演示][Link 1]

按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。

[https://codepen.io/comehope/pen/vaPGRz][https_codepen.io_comehope_pen_vaPGRz]

## 可交互视频 ##

此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。

请用 chrome, safari, edge 打开观看。

[https://scrimba.com/p/pEgDAM/cz32DUd][https_scrimba.com_p_pEgDAM_cz32DUd]

## 源代码下载 ##

[本地下载][Link 2]

每日前端实战系列的全部源代码请从 github 下载：

[https://github.com/comehope/front-end-daily-challenges][https_github.com_comehope_front-end-daily-challenges]

## 代码解读 ##

定义 dom，容器代表卡车，包含的 2 个子元素代表车头和尾气；`<hr>` 代表道路：

居中显示，同时道路与页面之间留出空间：

body {
        margin: 10%;
        padding-top: 10%;
    }

画出卡车车厢：

.truck {
        width: 15em;
        height: 5em;
        font-size: 10px;
        background-color: #444;
        border-radius: 0.4em;
    }

用伪元素画出车厢的车轮：

.truck {
        position: relative;
    }
    
    .truck::before,
    .truck::after {
        content: '';
        position: absolute;
        box-sizing: border-box;
        width: 2em;
        height: 2em;
        background-color: #444;
        border: 0.1em solid white;
        border-radius: 50%;
        bottom: -1em;
    }
    
    .truck::before {
        left: 0.6em;
    }
    
    .truck::after {
        right: 0.6em;
    }

画出车头：

.cab {
        position: absolute;
        width: 3.3em;
        height: 2.5em;
        background-color: #333;
        left: -3.5em;
        bottom: 0;
        border-radius: 40% 0 0.4em 0.4em;
    }
    
    .cab::before {
        content: '';
        position: absolute;
        width: 2em;
        height: 1.5em;
        background-color: #333;
        top: -1.5em;
        right: 0;
        border-radius: 100% 0 0 0;
    }

画出车头的车轮：

.cab::after {
        content: '';
        position: absolute;
        box-sizing: border-box;
        width: 2em;
        height: 2em;
        background-color: #444;
        border: 0.1em solid white;
        border-radius: 50%;
        bottom: -1em;
        left: 0.5em;
    }

画出尾气的初始状态：

.smoke,
    .smoke::before,
    .smoke::after {
        content: '';
        position: absolute;
        width: 1em;
        height: 1em;
        background-color: #333;
        right: -0.1em;
        bottom: -0.5em;
        border-radius: 50%;
    }

增加排出尾气的动画：

.smoke {
        animation: smoke-1 2s infinite;
    }
    
    .smoke::before {
        animation: smoke-2 2s infinite;
    }
    
    .smoke::after {
        animation: smoke-3 2s infinite;
    }
    
    @keyframes smoke-1 {
        to {
            width: 3em;
            height: 3em;
            right: -3em;
            bottom: 0.5em;
        }
    }
    
    @keyframes smoke-2 {
        to {
            width: 2.5em;
            height: 2.5em;
            right: -6em;
            bottom: 0.8em;
        }
    }
    
    @keyframes smoke-3 {
        to {
            width: 3.5em;
            height: 3.5em;
            right: -4em;
            bottom: 0.2em;
        }
    }

增加尾气的飘散效果：

.smoke {
        animation:
            drift 2s infinite,
            smoke-1 2s infinite;
    }
    
    .smoke::before {
        animation: 
            drift 3s infinite,
            smoke-2 3s infinite;
    }
    
    .smoke::after {
        animation: 
            drift 4s infinite,
            smoke-3 4s infinite;
    }
    
    @keyframes drift {
        0%, 100% {
            filter: opacity(0);
        }
    
        15% {
            filter: opacity(0.9);
        }
    }

增加卡车行驶的动画效果：

.truck {
        animation: 
            move 5s infinite;
    }
    
    @keyframes move {
        0% {
            margin-left: 90%;
        }
    
        50% {
            margin-left: 45%;
        }
    
        100% {
            margin-left: 0;
        }
    
        0%, 100% {
            filter: opacity(0);
        }
    
        10%, 90% {
            filter: opacity(1);
        }
    }

增加卡片行驶中颠簸的动画效果：

.truck {
        animation: 
            put-put 2s infinite,
            move 10s infinite;
    }
    
    @keyframes put-put {
        0% {
            margin-top: 0;
            height: 5em;
        }
    
        5% {
            margin-top: -0.2em;
            height: 5.2em;
        }
    
        20% {
            margin-top: -0.1em;
            height: 5em;
        }
    
        35% {
            margin-top: 0.1em;
            height: 4.9em;
        }
    
        40% {
            margin-top: -0.1em;
            height: 5.1em;
        }
    
        60% {
            margin-top: 0.1em;
            height: 4.9em;
        }
    
        75% {
            margin-top: 0;
            height: 5em;
        }
    
        80% {
            margin-top: -0.4em;
            height: 5.2em;
        }
    
        100% {
            margin-top: 0.1em;
            height: 4.9em;
        }
    }

大功告成！

原文地址：https://segmentfault.com/a/1190000015982054

[1446586357-5b70ceb1d54c1_articlex.gif]: /images/20220407/ef07b7490b23494a9eb44e76d6a4e7a6.png
[Link 1]: https://www.jqhtml.com/yanshi?demourl=%2Fwp-content%2Fuploads%2F2018%2F11%2Ffront-end-daily-challenges-master%2F104-truck-loader&demotitle=%E7%94%A8%E7%BA%AF%20CSS%20%E5%88%9B%E4%BD%9C%E4%B8%80%E4%B8%AA%E8%B4%A7%E8%BD%A6%20loader
[https_codepen.io_comehope_pen_vaPGRz]: https://codepen.io/comehope/pen/vaPGRz
[https_scrimba.com_p_pEgDAM_cz32DUd]: https://scrimba.com/p/pEgDAM/cz32DUd
[Link 2]: http://www.jqhtml.com/20674.html
[https_github.com_comehope_front-end-daily-challenges]: https://github.com/comehope/front-end-daily-challenges