关于svg:SVG-动画开发实战-SVG-描边动画Stroke

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✏️ SVG 描边动画（Stroke）

演示

查看在线版本

  • Polygon’s PlayStation 4 Review
  • vivus.js – svg animation

原理

要实现下面酷炫的描边动画，首先咱们须要理解 SVG 中实现描边动画的三个相干属性：别离是 stroke、stroke-dasharray、stroke-dashoffset。这三个属性作为外观显示属性，都能够作为 CSS 属性来应用。

stroke

SVG 中的 stroke 属性用来管制绘制描边的形式，咱们也能够应用 CSS 来管制 SVG 的描边款式。

https://codepen.io/xiaoluobod…

stroke-dasharray

咱们晓得在 CSS 中实现虚线边框，要应用 border: 1px dashed #f4a;；在 SVG 中要实现虚线成果就要应用 stroke-dasharray 属性。

https://codepen.io/xiaoluobod…

stroke-dashoffset

stroke-dashoffset 属性用来指定门路从开始地位的偏移量。通过指定偏移量会让绘制好的线偏移

原来的地位一段空白

https://codepen.io/xiaoluobod…

动起来

那么联合下面三个属性，咱们试着动静扭转 stroke-dashoffset 属性，看看会产生什么。通过动静扭转偏移量属性，联合设定好的 width 以及 stroke-dasharray 属性，会让原来动态的线有一种用画笔描绘出来的成果。

https://codepen.io/xiaoluobod…

实战

上面咱们应用 GreenSock 实现描边成果，GreenSock 提供了 DrawSVGPlugin 用于管制各种图形的描边成果，原理次要是通过管制下面学过的 stroke-dasharray、stroke-dashoffset 两个 CSS 属性来实现动画成果。

获取 SVG 代码

这里就应用 vivus 中的 Hi There 动画 作为 Demo，关上 vivus 官网，关上开发者工具，这里应用的是 Chrome，选中 Hi There dom 元素，能够看到 Hi There 的 SVG 代码。咱们选中元素右键复制进去。

失去如下代码：

<div class="bloc bloc-head">
  <svg height="300" xmlns="http://www.w3.org/2000/svg" x="0px" y="0px" viewBox="0 0 404.7 354" enable-background="new 0 0 404.7 354" id="hi-there" onclick="hi.reset().play();">

    <!-- HI -->
    <path data-duration="10" d="M324.6,61.2c16.6,0,29.5-12.9,29.5-29.5c0-16.6-12.9-29.5-29.5-29.5c-16.6,0-29.5,12.9-29.5,29.5C295.1,48.4,308,61.2,324.6,61.2z" style="stroke-dasharray: 186, 226; stroke-dashoffset: 0;"></path>
    <path data-duration="130" d="M366.2,204.2c-9.8,0-15-5.6-15-15.1V77.2h-85v28h19.5c9.8,0,8.5,2.1,8.5,11.6v72.4c0,9.5,0.5,15.1-9.3,15.1H277h-20.7c-8.5,0-14.2-4.1-14.2-12.9V52.4c0-8.5,5.7-12.3,14.2-12.3h18.8v-28h-127v28h18.1c8.5,0,9.9,2.1,9.9,8.9v56.1h-75V53.4c0-11.5,8.6-13.3,17-13.3h11v-28H2.2v28h26c8.5,0,12,2.1,12,7.9v142.2c0,8.5-3.6,13.9-12,13.9h-21v33h122v-33h-11c-8.5,0-17-4.1-17-12.2v-57.8h75v58.4c0,9.1-1.4,11.6-9.9,11.6h-18.1v33h122.9h5.9h102.2v-33H366.2z" style="stroke-dasharray: 2216, 2256; stroke-dashoffset: 0;"></path>

    <path data-async=""data-delay="20"d="M358.8,82.8c11.1-4.2,18.8-14.7,18.8-27.5c0-8.5-3.4-16-8.9-21.3"style="stroke-dasharray: 60, 100; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M124.2,105.7V77c0-11.5,9.1-13.8,17.5-13.8h10.5V44.7"style="stroke-dasharray: 84, 124; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M147.9,40.2L171.2,63.2L175.7,63.2"style="stroke-dasharray: 38, 78; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M295.1,32.1L275.2,12.2"style="stroke-dasharray: 29, 69; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M266.2,204.7V75.9c0-8.5,5.2-12.8,13.7-12.8h18.3V44.7"style="stroke-dasharray: 187, 227; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M265.9,105.2L289.2,129.2L293.7,129.2"style="stroke-dasharray: 38, 78; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M374.2,204.7L374.2,94.2L358.8,82.8L351.2,77.2"style="stroke-dasharray: 140, 180; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M148.2,237.2L171.2,261.2L294.6,261.2L300.5,261.2L402.2,261.2L402.2,228.2L379.2,204.2"style="stroke-dasharray: 331, 371; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M124.2,204.7L124.2,157.2L175.7,157.2"style="stroke-dasharray: 99, 139; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M147.7,228.2L129.2,204.2"style="stroke-dasharray: 31, 71; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M7.2,237.3L30.2,261.2L152.2,261.2L152.2,241.7"style="stroke-dasharray: 175, 215; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M1.9,40.2L26,63.2L39.7,63.2"style="stroke-dasharray: 48, 88; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M129.2,12.2L148.2,33.2"style="stroke-dasharray: 29, 69; stroke-dashoffset: 0;"></path>
    <path data-async=""d="M303.9,53L328.1,77.2"style="stroke-dasharray: 35, 75; stroke-dashoffset: 0;"></path>

    <path d="M345.1,10.5L368.7,34" style="stroke-dasharray: 34, 74; stroke-dashoffset: 0;"></path>

    <!-- there -->
    <path data-delay="30" data-duration="60" stroke-linecap="round" stroke-linejoin="round" d="M76.8,337.3c0,0,1.9,12.2,13.1,12.2c22.1,0,23.8-1.8,59-66.4c-19.7,35.7-36.4,66.2-19.3,66.2c15.2,0,22.9-14.2,28.3-23.7c3.3-0.5,24-3.2,35-25.5c4-8.1,4.1-17.8-8.1-15.2c-5.6,1.2-13.1,14.8-15.7,19.2c-7.6,12.7-22.4,45.2-22.4,45.2s10.3-22.4,21.5-22.4c15.5,0-9.4,22.4,4.7,22.4c4.9,0,11.7-11.4,16.6-20.9c7.5,4.7,19.7,1.7,24.5-8.1c10.1-20.4-14.4-12.8-24.5,8.1c-5.5,11.3-2.2,21.1,11.2,21.1c16.4,0,26.1-28.3,30.5-37.5c9.9,2.5,14,2.5,22.7-1.1c-3.5,5.1-24,38.1-8.3,38.1c6.7,0,11.7-11.4,16.6-20.9c7.5,4.7,19.7,1.7,24.5-8.1c10.1-20.4-14.4-12.8-24.5,8.1c-5.5,11.3-2.2,21.1,11.2,21.1c16.4,0,20.6-4,24.7-10.5" style="stroke-dasharray: 851, 891; stroke-dashoffset: 0;"></path>

    <path stroke-linecap="round" stroke-linejoin="round" d="M157.3,300.8c3.8-2.3-29,0.8-35.6,3.2" style="stroke-dasharray: 37, 77; stroke-dashoffset: 0;"></path>
  </svg>
</div>

剖析动画时间轴

仔细观察 vivus 中的 Hi There 的描边动画中一共有四个阶段：

  1. 先描边一个 Hi 字母的圆点
  2. 而后描边 Hi 字母
  3. 再描边 Hi 字母的 3D 边框
  4. 最初描边 there 单词

咱们给要描边的图形，例子中会波及到 path、polyline、line 等定义好 class，用于抉择。将无用 vivus 属性去掉，优化后的代码如下：

<div class="bloc bloc-head">
  <svg height="300" xmlns="http://www.w3.org/2000/svg" x="0px" y="0px" viewBox="0 0 404.7 354" id="hi-there">

    <!-- HI -->
    <path class="hi-o" fill="none" stroke="#FFFFFF" stroke-width="4" d="M324.6,61.2c16.6,0,29.5-12.9,29.5-29.5c0-16.6-12.9-29.5-29.5-29.5c-16.6,0-29.5,12.9-29.5,29.5C295.1,48.4,308,61.2,324.6,61.2z" />
    <path class="hi" fill="none" stroke="#FFFFFF" stroke-width="4" d="M366.2,204.2c-9.8,0-15-5.6-15-15.1V77.2h-85v28h19.5c9.8,0,8.5,2.1,8.5,11.6v72.4c0,9.5,0.5,15.1-9.3,15.1H277h-20.7c-8.5,0-14.2-4.1-14.2-12.9V52.4c0-8.5,5.7-12.3,14.2-12.3h18.8v-28h-127v28h18.1c8.5,0,9.9,2.1,9.9,8.9v56.1h-75V53.4c0-11.5,8.6-13.3,17-13.3h11v-28H2.2v28h26c8.5,0,12,2.1,12,7.9v142.2c0,8.5-3.6,13.9-12,13.9h-21v33h122v-33h-11c-8.5,0-17-4.1-17-12.2v-57.8h75v58.4c0,9.1-1.4,11.6-9.9,11.6h-18.1v33h122.9h5.9h102.2v-33H366.2z" />

    <path fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" d="M358.8,82.8c11.1-4.2,18.8-14.7,18.8-27.5c0-8.5-3.4-16-8.9-21.3" />
    <path fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" d="M124.2,105.7V77c0-11.5,9.1-13.8,17.5-13.8h10.5V44.7" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="147.9,40.2 171.2,63.2 175.7,63.2" />
    <line fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" x1="295.1" y1="32.1" x2="275.2" y2="12.2" />
    <path fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" d="M266.2,204.7V75.9c0-8.5,5.2-12.8,13.7-12.8h18.3V44.7" />
    <polyline fill="none" class="threedline" class="threedline" stroke="#FFFFFF" stroke-width="4" points="265.9,105.2 289.2,129.2 293.7,129.2" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="374.2,204.7 374.2,94.2 358.8,82.8 351.2,77.2" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="148.2,237.2 171.2,261.2 294.6,261.2 300.5,261.2 402.2,261.2 402.2,228.2 379.2,204.2" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="124.2,204.7 124.2,157.2 175.7,157.2" />
    <line fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" x1="147.7" y1="228.2" x2="129.2" y2="204.2" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="7.2,237.3 30.2,261.2 152.2,261.2 152.2,241.7" />
    <polyline fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" points="1.9,40.2 26,63.2 39.7,63.2" />
    <line fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" x1="129.2" y1="12.2" x2="148.2" y2="33.2" />
    <line fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" x1="303.9" y1="53" x2="328.1" y2="77.2" />
    <line fill="none" class="threedline" stroke="#FFFFFF" stroke-width="4" x1="345.1" y1="10.5" x2="368.7" y2="34" />

    <!-- there -->
    <path class="there" fill="none" stroke="#FFFFFF" stroke-width="4" stroke-linecap="round" stroke-linejoin="round" d="M76.8,337.3c0,0,1.9,12.2,13.1,12.2c22.1,0,23.8-1.8,59-66.4c-19.7,35.7-36.4,66.2-19.3,66.2c15.2,0,22.9-14.2,28.3-23.7c3.3-0.5,24-3.2,35-25.5c4-8.1,4.1-17.8-8.1-15.2c-5.6,1.2-13.1,14.8-15.7,19.2c-7.6,12.7-22.4,45.2-22.4,45.2s10.3-22.4,21.5-22.4c15.5,0-9.4,22.4,4.7,22.4c4.9,0,11.7-11.4,16.6-20.9c7.5,4.7,19.7,1.7,24.5-8.1c10.1-20.4-14.4-12.8-24.5,8.1c-5.5,11.3-2.2,21.1,11.2,21.1c16.4,0,26.1-28.3,30.5-37.5c9.9,2.5,14,2.5,22.7-1.1c-3.5,5.1-24,38.1-8.3,38.1c6.7,0,11.7-11.4,16.6-20.9c7.5,4.7,19.7,1.7,24.5-8.1c10.1-20.4-14.4-12.8-24.5,8.1c-5.5,11.3-2.2,21.1,11.2,21.1c16.4,0,20.6-4,24.7-10.5" />
    <path class="there" fill="none" stroke="#FFFFFF" stroke-width="4" stroke-linecap="round" stroke-linejoin="round" d="M157.3,300.8c3.8-2.3-29,0.8-35.6,3.2" />
  </svg>
</div>

实现动画

GreenSock 提供了 timeline 用于创立间断的错开补间动画，很好了解，动画是按时间轴有序进行的。

借助 DrawSVGPlugin 实现了将 SVG path 从 0% 绘制到 100% 的动画成果。

// 创立时间轴
let tl = gsap.timeline({repeat: -1})

/**
 * 1、先描边一个 Hi 字母的圆点
 * 2、而后描边 Hi 字母
 * 3、再描边 Hi 字母的 3D 边框
 * 4、最初描边 there 单词
 */
tl
  .fromTo(
    '.hi-o',
    {drawSVG: "0%"},
    {duration: .3, drawSVG: "100%", stagger: 0.1},
  )
  .fromTo(
    '.hi',
    {drawSVG: "0%"},
    {duration: 3, drawSVG: "100%", stagger: 0.2},
  )
  .fromTo(
    '.threedline',
    {drawSVG: "0%"},
    {duration: 0.8, drawSVG: "100%"},
    "+=0.2"
  )
  .fromTo(
    '.there',
    {drawSVG: "0%"},
    {duration: 2, drawSVG: "100%", stagger: 0.5}
  )

最终成果：

https://codepen.io/xiaoluobod…

参考

  • https://www.polygon.com/a/ps4…
  • http://maxwellito.github.io/v…
  • https://developer.mozilla.org…
  • https://css-tricks.com/svg-li…

对于

本文是《SVG 动画开发实战》系列文章第五章。

Notion 版本

小册是在 Notion 上实现撰写的，所以我保留了 Notion 的分享版本，你也能够点击这里查看。

GitHub 版本

小册提供了 GitHub 版本的在线浏览体验，传送门

微信公众号版本

关注我的技术公号，同样也能够找到此小册系列，目前在更新中。。。

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发表至： svg
2020-12-23
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