使用 CSS3/JS 的 SVG 径向擦除动画

How can i achieve a radial wipe animation in CSS3 or JS? It's seems so simple but I can't figure it out.

这是使用 jQuery 的基本方法。可能有可用的插件可以简化此操作。

JSFiddle 演示

HTML

<svg xmlns="http://www.w3.org/2000/svg"
     xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">

    <!-- 0 degrees arc -->
    <path d="M100,100 v-100 a100,100 0 0,1 0,0 z"
          id="circle-wipe" fill="#999" stroke-width="0" />
</svg>

CSS

svg {
    width: 200px;
    height: 200px;
}

jQuery

// Utility function for drawing the circle arc

function drawCircleArc(elem, angle) {
    var endAngleDeg = angle - 90;
    var endAngleRad = (endAngleDeg * Math.PI) / 180;
    var largeArcFlag = (angle < 180 ? '0' : '1');

    var endX = Math.cos(endAngleRad) * 100;
    var endY = 100 + (Math.sin(endAngleRad) * 100);

    var data = 'M100,100 v-100 a100,100 0 ' + largeArcFlag + ',1 ' +
                endX + ',' + endY + ' z';

    $(elem).attr('d', data);
}

// Code for running the animation

var arcAngle = 0;        // Starts at 0, ends at 360
var arcAngleBy = 10;     // Degrees per frame
var arcAngleDelay = 50;  // Duration of each frame in msec

function updateCircleWipe() {
    arcAngle += arcAngleBy;

    drawCircleArc('#circle-wipe', arcAngle);

    if (arcAngle < 360) {
        setTimeout(function(){ updateCircleWipe(); }, arcAngleDelay);
    }
}

setTimeout(function(){ updateCircleWipe(); }, arcAngleDelay);

也可以看看：

• SVG Path(w3schools.com)
• Paths(w3.org)