svg 环形进度条加读取进度效果（读数效果）-- 移动端 rem 适配
项目需求做一个环形进度条的效果需要有一个读数的效果，在网上查阅相关资料后整理了下
gif 效果如下，录制的不是很流畅多停留下时间看下 都是动态的效果
代码如下
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
<link href="base.css" rel="stylesheet" type="text/css">
<script src="jquery.min.js">script>
<style>
* {
box-sizing: border-box;
}
html,
body {
margin: 0 0;
padding: 0;
height: 100%;
}
body {
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
background: #212121;
font-family: 'Roboto', Helvetica, Arial, sans-serif;
display: flex;
align-items: center;
justify-content: center;
width: 100%;
height: 100%;
}
/* svg最外层 */
.donut {
position: relative;
}
/* 文字最外层 */
.donut__copy {
text-align: center;
width: 100%;
height: 100%;
padding-top: 1.2rem;
top: 0;
left: 0;
position: absolute;
}
.donut__title {
display: block;
margin: 0;
padding: 0;
}
.donut-speed {
font-size:0.26rem;
color: rgba(255, 255, 255, 0.7);
display:block;
text-align: center;
}
/* 中间文字和% 样式 */
.donut__title,
.donut__spic {
color: #ffffff;
font-weight: 200;
}
/* 中间文字 */
.donut__title {
font-size: 1rem;
position: relative;
margin-top:0.4rem;
}
/* % 符号 */
.donut__spic {
position: absolute;
top: 0.5rem;
font-size: 0.26rem;
line-height: 1em;
color: rgba(255, 255, 255, 0.4);
}
/* svg 旋转 */
.donut__svg {
transform: rotate(90deg);
}
/* 线条渲染 cubic-bezier 是贝塞尔曲线*/
/*
SVG元素有两个画笔属性 stroke-dasharray 和 stroke-dashoffset，前者是用来定义画笔线型（stroke pattern），后者定义线型起始点位置。这两个属性可以用来构造很多的图形效果（尤其是虚线），在这里我们使用其中一个特例，即无间隔的单个线条填充。填满整个圆周的长度为2*3.14*半径 = 周长（圆周长计算公式为Circumstance =2*PI*Radius）*/
.donut__svg__circle--one {
stroke-dasharray: 12.566370614359173rem;
stroke-dashoffset: 12.566370614359173rem;
transition: stroke-dashoffset 1200ms cubic-bezier(.28,.56,0,1.04);
}
style>
head>
<body>
<div class="donut">
<svg width="4.4rem" height="4.4rem" xmlns="http://www.w3.org/2000/svg" version="1.1" class="donut__svg">
<circle id="donut-graph-x" class="donut__svg__scrim" r="2rem" cy="2.2rem" cx="2.2rem" stroke-width="0.25rem" stroke="#333" fill="none" />
<circle id="donut-graph" class="donut__svg__circle--one" r="2rem" cy="2.2rem" cx="2.2rem" stroke-width="0.25rem" stroke="url(#purple)" stroke-linejoin="round" stroke-linecap="round" fill="none" />
<defs>
<linearGradient id="purple" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" stop-color="#92ce56" />
<stop offset="100%" stop-color="#59ce61" />
linearGradient>
defs>
svg>
<div class="donut__copy">
<span class="donut__title">
<span class="js-donut-figure">span>
<span class="donut__spic">sspan>
span>
div>
div>
<script>
window.onload = function () {
'use strict';
var ProgressCircle = (function() {
function ProgressCircle(percent, radius, elementClass) {
this._percent = percent;
this._radius = radius;
this._elementClass = elementClass;
}
ProgressCircle.prototype.calcDashOffset = function() {
var circumference;
circumference = Math.PI * (2 * this._radius); //计算圆圈的周长
return Math.round(circumference - this._percent / 100 * circumference) / 100 + 'rem'; //计算圆圈要渲染的 长度
};
//渲染进度条
ProgressCircle.prototype.createCSS = function() {
return $("." + this._elementClass + " .donut__svg .donut__svg__circle--one").css('stroke-dashoffset', this.calcDashOffset());
};
//读数效果
ProgressCircle.prototype.updateText = function() {
var num, i, s,_this;
num = $("." + this._elementClass + " .js-donut-figure");
i = 0;
_this = this;
s = setInterval(function(){
i++;
console.log(i, _this._percent);
if(i >= _this._percent){
clearInterval(s);
}
num.html(i);
},10);
};
ProgressCircle.prototype.init = function() {
var _this = this;
setTimeout(function(){
_this.updateText();
return _this.createCSS();
},1000);
};
return ProgressCircle;
})();
var progress = new ProgressCircle(50, 200, 'donut');
progress.init();
}
script>
body>
html>代码中的 base.css 代码如下 依靠媒介查询改变 html根元素的的文字大小来实现rem 适配
@charset "utf-8";
body, h1, h2, h3, h4, h5, h6, blockquote, p, pre, dl, dd, menu, ol, ul, caption, th, td, form, fieldset, legend, input, button, textarea {
margin: 0;
padding: 0
}
h1, h2, h3, h4, h5, h6 {
font-size: 100%
}
menu, ol, ul {
list-style: none
}
table {
border-collapse: collapse;
border-spacing: 0
}
fieldset, img {
border: 0
}
legend {
display: none
}
a:active, a:focus {
outline: none
}
address, cite, dfn, em, var {
font-style: normal
}
code, kbd, pre, samp {
font-family: 'courier new', courier, monospace
}
input, button, textarea, select {
font-size: 100%
}
abbr[title] {
border-bottom: 1px dotted;
cursor: help
}
a {
text-decoration: none
}
.clear {
zoom: 1
}
.clear:after {
content: "";
display: block;
clear: both
}
@media screen and (min-width: 320px) {
html {
font-size: 50px
}
}
@media screen and (min-width: 360px) {
html {
font-size: 56px
}
}
@media screen and (min-width: 400px) {
html {
font-size: 63px
}
}
@media screen and (min-width: 440px) {
html {
font-size: 69px
}
}
@media screen and (min-width: 480px) {
html {
font-size: 75px
}
}
html {
font-size: 15.625vw
}
@media screen and (min-width: 640px) {
html {
font-size: 100px
}
}原文地址： 原文有动画演示 并且是pc端的，我是根据原文思路修改的代码来实现的效果适配的移动端，有兴趣的可以看下
http://www.techbrood.com/zh/news/css3/%E4%BD%BF%E7%94%A8svg%E5%92%8Ccss3%E5%88%9B%E5%BB%BA%E5%9C%86%E5%BD%A2%E8%BF%9B%E5%BA%A6%E6%9D%A1%E5%8A%A8%E7%94%BB.html