使用纯css实现赛车loader动画效果的方法(html5,web开发)

效果预览

源代码下载

https://github.com/comehope/front-end-daily-challenges

代码解读

定义 dom，容器中包含 1 个 .car 元素，它的 2 个子元素分别代表车身和车轮：

<figure class="loader"> <div class="car"> <span class="body"></span> <span class="wheels"></span> </div></figure>

居中显示：

body { margin: 0; height: 100vh; display: flex; align-items: center; justify-content: center; background-color: #333;}

定义容器尺寸和车的颜色：

.loader { width: 11.7em; height: 4.2em; color: lightcyan; position: relative;}

画出底盘：

.car { position: absolute; width: inherit; height: 2em; background-color: currentColor; top: 1.5em; border-radius: 0 5em 1em 0 / 0 4em 1em 0;}

画出尾冀：

.car::before { content: ''; position: absolute; width: 0; height: 0; border: 0.6em solid transparent; border-left-width: 0; border-right-color: currentColor; transform-origin: left; transform: rotate(-45deg); top: -0.5em;}

（这时看起来有点儿像飞机，哈哈~~）

画出车身：

.body { position: absolute; width: 7.5em; height: 3.5em; box-sizing: border-box; border: 0.4em solid; border-radius: 3em 4.5em 0 0 / 3em 4em 0 0; top: -1.5em; left: 1.2em;}

用伪元素画出车窗：

.body::before { content: ''; position: absolute; width: 3.5em; height: inherit; background-color: currentColor; border-top-left-radius: inherit; left: -0.4em; top: -0.4em;}

画出车轮的轮廓：

.wheels::before,.wheels::after { content: ''; position: absolute; box-sizing: border-box; width: 2.6em; height: 2.6em; background-color: #333; border-radius: 50%; bottom: -1em;}

画出轮毂：

.wheels::before,.wheels::after { border: 0.3em solid #333; background-image: linear-gradient( 135deg, transparent 45%, currentColor 46%, currentColor 54%, transparent 55% ), linear-gradient( 90deg, transparent 45%, currentColor 46%, currentColor 54%, transparent 55% ), linear-gradient( 45deg, transparent 45%, currentColor 46%, currentColor 54%, transparent 55% ), linear-gradient( 0deg, transparent 45%, currentColor 46%, currentColor 54%, transparent 55% ), radial-gradient( currentColor 29%, transparent 30%, transparent 50%, currentColor 51% );}

把车轮定位到左右两侧：

.wheels::before { left: 1.2em;}.wheels::after { right: 0.8em;}

接下来制作动画效果。

增加表示风影的 dom 元素 .strikes，它包含 5 个子元素：

<figure class="loader"> <p class="car"> <span class="body"></span> <span class="wheels"></span> </p> <p class="strikes"> <span></span> <span></span> <span></span> <span></span> <span></span> </p></figure>

画出 5 段短细线：

.strikes { position: absolute; width: 1em; height: inherit; border: 1px dashed white; display: flex; flex-direction: column; justify-content: space-between;}.strikes span { height: 0.1em; background-color: lightcyan;}

增加风影飘逝的动画效果，定义 css 变量，设置动画延时：

.strikes span { animation: drift 0.2s linear infinite; animation-delay: calc((var(--n) - 1) * 0.05s);}@keyframes drift { from { transform: translate(3.5em); } to { transform: translate(-8em); filter: opacity(0); }}.strikes span:nth-child(1) { --n: 1;}.strikes span:nth-child(2) { --n: 2;}.strikes span:nth-child(3) { --n: 3;}.strikes span:nth-child(4) { --n: 4;}.strikes span:nth-child(5) { --n: 5;}

增加轮子转动动画效果：

.wheels::before,.wheels::after { animation: rotating 0.5s linear infinite;}@keyframes rotating { to { transform: rotate(1turn); }}

增加车身颠簸的动画效果：

.car { animation: run 0.25s linear infinite;}@keyframes run { 0% { transform: translate(0.2em, 0.1em) rotate(0deg); } 20% { transform: translate(0.1em, 0.2em) rotate(1deg); } 40% { transform: translate(0.1em, -0.1em) rotate(-1deg); } 60% { transform: translate(-0.1em, 0.2em) rotate(0deg); } 80% { transform: translate(-0.1em, 0.1em) rotate(1deg); } 100% { transform: translate(0.2em, 0.1em) rotate(-1deg); }}

大功告成！