如何在运动路径上有效地反转SVG(SMIL)动画？

Question

我正在尝试确定如何有效地反转使用该元素animateMotion的d属性的SVG动画(使用SMIL)path.我需要动画在形状周围逆时针运行.

可在此处找到当前动画,相关代码如下.

document.getElementById("svgobject").pauseAnimations();

<svg version="1.1" id="svgobject" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="451.5px" height="451.5px" viewBox="0 0 461.5 461.5" enable-background="new 0 0 461.5 461.5" xml:space="preserve">
  <g>
    <path fill="none" stroke="black"
          d="M446.85,280.187c0,30.296-24.56,54.854-54.854,54.854H60.239c-30.296,0-54.854-24.559-54.854-54.854l0,0c0-30.296,24.559-54.854,54.854-54.854h331.756C422.29,225.333,446.85,249.891,446.85,280.187L446.85,280.187z"/>
    <rect id="rect" x="0" y="0" width="50" height="20" fill="gray" stroke="black" stroke-width="1" transform="translate(-25, -10)">
      <animateMotion path="M446.85,280.187c0,30.296-24.56,54.854-54.854,54.854H60.239c-30.296,0-54.854-24.559-54.854-54.854l0,0c0-30.296,24.559-54.854,54.854-54.854h331.756C422.29,225.333,446.85,249.891,446.85,280.187L446.85,280.187z"
        begin= "0s" dur="2s" repeatCount="1" rotate="auto" fill="freeze" />
    </rect>
  </g>

  <!--start and stop animation-->
  <g onclick="document.getElementById('svgobject').unpauseAnimations()"
     transform="translate(160 100)">
    <rect width="60" height="30" rx="10" stroke="black" fill-opacity="0.2"/>
    <text style="font: 16px Arial Black; fill: white; stroke: black;"
          transform="translate(2 20)">START</text>
  </g>
  <g onclick="document.getElementById('svgobject').pauseAnimations()"
     transform="translate(260 100)">
    <rect width="60" height="30" rx="10" stroke="black" fill-opacity="0.2"/>
    <text style="font: 16px Arial Black; fill: white; stroke: black;"
          transform="translate(5 20)">STOP</text>
  </g>
</svg>

据我所知,我可以手动反转SVG路径数据命令,包括moveto(M,m),lineto(L,l),curveto(C,c)等.

鉴于我需要反转的路径坐标的数量(除了这个动画中的那些),我正在尝试确定是否有更有效的方法来执行此操作.

Answer 1

您可以使用keyPoints和keyTimes属性来反转动画的方向.

<animateMotion path="..." begin= "0s" dur="2s" repeatCount="1" rotate="auto"
               fill="freeze" keyPoints="1;0" keyTimes="0;1">

这里我们告诉运动从1(路径的末尾)到0(路径的开始).

这适用于Firefox,但遗憾的是不适用于Chrome.Chrome似乎被窃听了.

更新:

我发现与此相关的Chrome错误:https://code.google.com/p/chromium/issues/detail？id = 353108

如果calcMode是"节奏"(默认为),则keyTimes似乎被打破.如果您将其更改为其他内容,例如"线性:动画也可以在Chrome中正常运行.

<animateMotion path="..." begin= "0s" dur="2s" repeatCount="1" rotate="auto"
               fill="freeze" keyPoints="1;0" keyTimes="0;1" calcMode="linear">

在这里演示

在这里更新了Codepen