# 纯 CSS 实现波浪效果！

## 使用 SVG 实现波浪效果

<svg width="200px" height="200px" version="1.1" xmlns="http://www.w3.org/2000/svg">
<text class="liquidFillGaugeText" text-anchor="middle" font-size="42px" transform="translate(100,120)" style="fill: #000">50.0%</text>
<!-- Wave -->
<g id="wave">
<path id="wave-2" fill="rgba(154, 205, 50, .8)" d="M 0 100 C 133.633 85.12 51.54 116.327 200 100 A 95 95 0 0 1 0 100 Z">
<animate dur="5s" repeatCount="indefinite" attributeName="d" attributeType="XML" values="M0 100 C90 28, 92 179, 200 100 A95 95 0 0 1 0 100 Z;
M0 100 C145 100, 41 100, 200 100 A95 95 0 0 1 0 100 Z;
M0 100 C90 28, 92 179, 200 100 A95 95 0 0 1 0 100 Z"></animate>
</path>
</g>
<circle cx="100" cy="100" r="80" stroke-width="10" stroke="white" fill="transparent"></circle>
<circle cx="100" cy="100" r="90" stroke-width="20" stroke="yellowgreen" fill="none" class="percentage-pie-svg"></circle>
</svg>

## 使用 canvas 实现波浪效果

$(function() { let canvas =$("canvas");
let ctx = canvas[0].getContext('2d');
let radians = (Math.PI / 180) * 180;
let startTime = Date.now();
let time = 2000;
let clockwise = 1;
let cp1x, cp1y, cp2x, cp2y;

// 初始状态
// ctx.bezierCurveTo(90, 28, 92, 179, 200, 100);
// 末尾状态
// ctx.bezierCurveTo(145, 100, 41, 100, 200, 100);

requestAnimationFrame(function waveDraw() {
let t = Math.min(1.0, (Date.now() - startTime) / time);

if(clockwise) {
cp1x = 90 + (55 * t);
cp1y = 28 + (72 * t);
cp2x = 92 - (51 * t);
cp2y = 179 - (79 * t);
} else {
cp1x = 145 - (55 * t);
cp1y = 100 - (72 * t);
cp2x = 41 + (51 * t);
cp2y = 100 + (79 * t);
}

ctx.clearRect(0, 0, 200, 200);
ctx.beginPath();
ctx.moveTo(0, 100);
// 绘制三次贝塞尔曲线
ctx.bezierCurveTo(cp1x, cp1y, cp2x, cp2y, 200, 100);
// 绘制圆弧
ctx.arc(100, 100, 100, 0, radians, 0);
ctx.fillStyle = "rgba(154, 205, 50, .8)";
ctx.fill();
ctx.save();

if( t == 1 ) {
startTime = Date.now();
clockwise = !clockwise;
}

requestAnimationFrame(waveDraw);
});
})

## 纯 CSS 实现波浪效果

### 实现

body {
position: relative;
align-items: center;
min-height: 100vh;
background-color: rgb(118, 218, 255);
overflow: hidden;

&:before, &:after {
content: "";
position: absolute;
left: 50%;
min-width: 300vw;
min-height: 300vw;
background-color: #fff;
animation-name: rotate;
animation-iteration-count: infinite;
animation-timing-function: linear;
}

&:before {
bottom: 15vh;
animation-duration: 10s;
}

&:after {
bottom: 12vh;
opacity: .5;
animation-duration: 10s;
}
}

@keyframes rotate {
0% {
transform: translate(-50%, 0) rotateZ(0deg);
}
50% {
transform: translate(-50%, -2%) rotateZ(180deg);
}
100% {
transform: translate(-50%, 0%) rotateZ(360deg);
}
}

### 值得探讨的点

• 中间高，两边低的效果不符合物理学原理，看上去十分别扭；

CodePen Demo -- pure css wave

## 使用纯 CSS 实现波浪进度图

HTML 结构如下：

<div class="container">
<div class="wave"></div>
</div>

CSS 代码如下：

.wave {
position: relative;
width: 200px;
height: 200px;
background-color: rgb(118, 218, 255);

&::before,
&::after{
content: "";
position: absolute;
width: 400px;
height: 400px;
top: 0;
left: 50%;
background-color: rgba(255, 255, 255, .4);
transform: translate(-50%, -70%) rotate(0);
animation: rotate 6s linear infinite;
z-index: 10;
}

&::after {
background-color: rgba(255, 255, 255, .9);
transform: translate(-50%, -70%) rotate(0);
animation: rotate 10s linear -5s infinite;
z-index: 20;
}
}

@keyframes rotate {
50% {
transform: translate(-50%, -73%) rotate(180deg);
} 100% {
transform: translate(-50%, -70%) rotate(360deg);
}
}

## 一些小技巧

• 在动画过程中，利用 transform 对旋转椭圆进行轻微的位移、变形；
• 上面也演示到了，多个椭圆同时转动，赋予不同时长的动画，并且添加轻微的透明度，让整个效果更佳逼真。

## 最后

posted @ 2017-07-18 11:02 ChokCoco 阅读(...) 评论(...) 编辑 收藏