Question

我正在尝试制作圆形动画，
我目前有这个：http://jsfiddle.net/gf327jxu/1/

<svg width="100" height="100" class="circle">
   <circle cx="50" cy="50" r="40" />
</svg>

的CSS：

.circle{
stroke:green;
stroke-width:10;
fill:none;
}

我希望它像一个圆形进展一样动画，像这样：http://jsfiddle.net/andsens/mLA7X/但在SVG中，我需要顺时针方向，我怎么能实现这一点，这是否可能？

Answer 1

这是一个fiddle example。

注意：我使用了r = 57，因为周边是358.1，接近360 degrees。对于不同的r值，您需要计算stroke-dasharray

非常感谢@Robert Longson，@ErikDahlström和@Phrogz多年来的SO解决方案。这个小提琴只是他们的一个调整。

(function() {
  // math trick 2*pi*57 = 358, must be less than 360 degree 
  var circle = document.getElementById('green-halo');
  var myTimer = document.getElementById('myTimer');
  var interval = 30;
  var angle = 0;
  var angle_increment = 6;

  window.timer = window.setInterval(function() {
    circle.setAttribute("stroke-dasharray", angle + ", 20000");
    myTimer.innerHTML = parseInt(angle / 360 * 100) + '%';

    if (angle >= 360) {
      window.clearInterval(window.timer);
    }
    angle += angle_increment;
  }.bind(this), interval);
})()

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" viewBox="0 0 300 300" preserveAspectRatio="none" style="width:300; height:300; top:0; left:0;">
    <circle cx="100" cy="100" r="57" id="green-halo" fill="none" stroke="#00CC33" stroke-width="15" stroke-dasharray="0,20000" transform="rotate(-90,100,100)" />
    <text id="myTimer" text-anchor="middle" x="100" y="110" style="font-size: 36px;" >0%</text>
</svg>

Answer 2

const countdownNumberEl = document.getElementById('countdown-number');
const circle = document.getElementById('circle');

let countdown = 25;
const radius = Number(circle.getAttribute('r'));
const circumference = 2 * radius * Math.PI;

circle.style.transition = `all ${countdown}s linear`

countdownNumberEl.innerHTML = countdown;

function startTimer() {
  const interval = setInterval(() => {
    countdown = countdown - 1;
    countdownNumberEl.innerHTML = countdown;
    
    if (countdown === 0) {
      clearInterval(interval);
    }
  }, 1000);

  circle.setAttribute('stroke-dasharray', circumference);
  circle.setAttribute('stroke-dashoffset', circumference);
}

setTimeout(() => startTimer(), 0)

body {
  background: #333;
  font-family: sans-serif;
}

#countdown {
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  margin: 60px auto;
  height: 80px;
  width: 80px;
}

#countdown-number {
  color: darkgray;
}

svg {
  position: absolute;
  top: 0;
  right: 0;
  width: 100%;
  height: 100%;
  transform: rotateY(-180deg) rotateZ(-90deg);
}

<div id="countdown">
  <p id="countdown-number"></p>
  <svg>
    <circle r="24" cx="40" cy="40 "stroke-linecap="round" stroke-width="2" fill="none" stroke="black"></circle>
  </svg>
  <svg>
    <circle id="circle" r="24" cx="40" cy="40" stroke-linecap="round" stroke-width="2" fill="none" stroke="darkgray"></circle>
  </svg>
</div>

Answer 3

这是一个纯 svg 解决方案：codepen

<svg version="1.1" id="circle" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
  viewBox="0 0 100 100" xml:space="preserve">
    <circle fill="none" stroke="#000" stroke-width="4" stroke-mitterlimit="0" cx="50" cy="50" r="48" stroke-dasharray="360" stroke-linecap="round" transform="rotate(-90 ) translate(-100 0)" >
        <animate attributeName="stroke-dashoffset" values="360;0" dur="2s" repeatCount="indefinite"></animate>
    </circle>
</svg>

Answer 4

<!DOCTYPE html>
<html>
    <head>
        <title>svg circle animation</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <style>
            #XMLID_4_{
                stroke-dasharray: 1000;
                stroke-dashoffset: 2000;
                fill: #FFFFFF;
                stroke: #000000;
            }
            svg:hover #XMLID_4_{
                -webkit-animation: draw 3s forwards;
                animation: draw 3s;
            }
            @keyframes draw{
                from{
                    stroke-dashoffset: 1000;
                    fill:#efefef;
                    stroke:#ff5535;
                }
                to{
                    stroke-dashoffset: 0;   
                }
            }
            @-webkit-keyframes draw{
                from{
                    stroke:#ff5535;
                    stroke-dashoffset: 1000; 
                }
                to{
                    stroke-dashoffset: 0;   
                }
            }
        </style>
    </head>
    <body>
        <svg width="640" height="480" xmlns="http://www.w3.org/2000/svg">
        <g>
        <circle id="XMLID_4_"  stroke-width="3" stroke-miterlimit="10" cx="366.5" cy="135.6" r="44.7"/>
        </g>
        </svg>
    </body>
</html>

SVG圈动画

4 个答案: