javascript - SVG 动画 : sluggish/poor performance in Chrome

Question

我们正在开发一个相当复杂的场景，其中有很多移动部件，到目前为止还没有涉及任何 SVG 动画。

一切都很顺利并且表现良好，直到我们引入了一个带有几条虚线的 SVG，我们使用 stroke-dashoffset 属性对其进行了动画处理。

这在 Edge 或 Firefox 中完全没有区别，但在 Chrome 中，整个场景的动画变得不稳定和缓慢。

我们甚至为同一目的尝试了两种方法 - CSS 关键帧和 SVG 元素内的 SMIL - 但两者的表现同样糟糕。

是否有我们缺少的 Chrome 性能技巧？

编辑:例子

标记:

.stream {
  animation: stream 10s infinite;
}

@keyframes stream {
  100% {
    stroke-dashoffset: 100;
  }
}

<svg version="1.0" id="streams" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 225.32 66.19" enable-background="new 0 0 225.32 66.19" xml:space="preserve">
      <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" d="M107.38,50.54c0,0-6.78-84.52-106.51-22.2" />
      <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" d="M110.49,45.31c-0.63-13.01-4.56-44.87-27.83-43.8c-27.6,1.27-37.33,39.66-38.49,60.34"/>
      <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" d="M180.63,59.88c-0.69-9.65-3.6-30.18-15.76-45.51C148.44-6.34,131.85,2.22,128.87,5c-2.89,2.7-12.81,7.14-14.28,42"/>
      <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" d="M118.59,45.41c2.4-10.18,9.9-31.97,30.87-37.59c26.03-6.98,55.13,9.32,72.02,19.37"/>
</svg>

Answer 1

重复 How can I animate infinite marker movement down an SVG path without very high CPU usage?

这里真正的问题是糟糕的 svg 实现，参见 chrome bug

一种解决方法确实会降低 javascript 动画的帧速率，请参阅代码示例

这个特殊情况可以用虚线圆圈和 css 来完成 transform: rotate3d() .而且“GPU 转换”翻译/旋转在今天的 svg 实现中表现不佳。解决方法:将 svg 代码包装在 <div> 中并为 div 设置动画，瞧! cpu 下降到零。相关:crmarsh.com/svg-performance

const svg_elem = document.getElementById('streams')

const animateDashTime = 200 // milliseconds
let anim_dash_offset = 0
let animateDashTimer = null

function animateDashStep(){

  anim_dash_offset += 1

  svg_elem.setAttribute('style',
    '--stroke-dashoffset: '+anim_dash_offset);

  // repeat
  animateDashTimer = setTimeout(
    animateDashStep,
    animateDashTime
  )
}

// start
animateDashStep()

// stop
//clearTimeout(animateDashTimer)

<svg version="1.0" id="streams" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 225.32 66.19" enable-background="new 0 0 225.32 66.19" xml:space="preserve" 

  style="--stroke-dashoffset: 0"
>
  <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" 
  
    stroke-dasharray="3,4" 
    stroke-dashoffset="var(--stroke-dashoffset)" 

    d="M107.38,50.54c0,0-6.78-84.52-106.51-22.2"
  />
  <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" stroke-dashoffset="var(--stroke-dashoffset)" d="M110.49,45.31c-0.63-13.01-4.56-44.87-27.83-43.8c-27.6,1.27-37.33,39.66-38.49,60.34"
  />
  <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" stroke-dashoffset="var(--stroke-dashoffset)" d="M180.63,59.88c-0.69-9.65-3.6-30.18-15.76-45.51C148.44-6.34,131.85,2.22,128.87,5c-2.89,2.7-12.81,7.14-14.28,42"/>
  <path class="stream" fill="none" stroke="#000" stroke-width="1.75" stroke-linecap="round" stroke-miterlimit="10" stroke-dasharray="3,4" stroke-dashoffset="var(--stroke-dashoffset)" d="M118.59,45.41c2.4-10.18,9.9-31.97,30.87-37.59c26.03-6.98,55.13,9.32,72.02,19.37"/>
</svg>