uTools-Manuals/docs/vue/guide/transitioning-state.html

<div class="content guide with-sidebar transitioning-state-guide">
<h1>状态过渡</h1>
<p>Vue 的过渡系统提供了非常多简单的方法设置进入、离开和列表的动效。那么对于数据元素本身的动效呢，比如：</p>
<ul>
<li>数字和运算</li>
<li>颜色的显示</li>
<li>SVG 节点的位置</li>
<li>元素的大小和其他的属性</li>
</ul>
<p>这些数据要么本身就以数值形式存储，要么可以转换为数值。有了这些数值后，我们就可以结合 Vue 的响应式和组件系统，使用第三方库来实现切换元素的过渡状态。</p>
<h2 id="状态动画与侦听器"><a class="headerlink" href="#状态动画与侦听器" title="状态动画与侦听器"></a>状态动画与侦听器</h2><p>通过侦听器我们能监听到任何数值属性的数值更新。可能听起来很抽象，所以让我们先来看看使用 <a href="https://greensock.com/" rel="noopener" target="_blank">GreenSock</a> 一个例子：</p>
<pre><code class="hljs html"><span class="hljs-tag">&lt;<span class="hljs-name">script</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"https://cdnjs.cloudflare.com/ajax/libs/gsap/1.20.3/TweenMax.min.js"</span>&gt;</span><span class="undefined"></span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">div</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"animated-number-demo"</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">v-model.number</span>=<span class="hljs-string">"number"</span> <span class="hljs-attr">type</span>=<span class="hljs-string">"number"</span> <span class="hljs-attr">step</span>=<span class="hljs-string">"20"</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">p</span>&gt;</span>{{ animatedNumber }}<span class="hljs-tag">&lt;/<span class="hljs-name">p</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">div</span>&gt;</span></code></pre>
<pre><code class="hljs js"><span class="hljs-keyword">new</span> Vue({
  <span class="hljs-attr">el</span>: <span class="hljs-string">'#animated-number-demo'</span>,
  <span class="hljs-attr">data</span>: {
    <span class="hljs-attr">number</span>: <span class="hljs-number">0</span>,
    <span class="hljs-attr">tweenedNumber</span>: <span class="hljs-number">0</span>
  },
  <span class="hljs-attr">computed</span>: {
    <span class="hljs-attr">animatedNumber</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span>.tweenedNumber.toFixed(<span class="hljs-number">0</span>);
    }
  },
  <span class="hljs-attr">watch</span>: {
    <span class="hljs-attr">number</span>: <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">newValue</span>) </span>{
      TweenLite.to(<span class="hljs-keyword">this</span>.$data, <span class="hljs-number">0.5</span>, { <span class="hljs-attr">tweenedNumber</span>: newValue });
    }
  }
})</code></pre>
<script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/1.20.3/TweenMax.min.js"></script>
<div class="demo" id="animated-number-demo">
<input step="20" type="number" v-model.number="number"/>
<p>{{ animatedNumber }}</p>
</div>
<script>
new Vue({
  el: '#animated-number-demo',
  data: {
    number: 0,
    tweenedNumber: 0
  },
  computed: {
    animatedNumber: function() {
      return this.tweenedNumber.toFixed(0);
    }
  },
  watch: {
    number: function(newValue) {
      TweenLite.to(this.$data, 0.5, { tweenedNumber: newValue });
    }
  }
})
</script>
<p>当你把数值更新时，就会触发动画。这个是一个不错的演示，但是对于不能直接像数字一样存储的值，比如 CSS 中的 color 的值，通过下面的例子我们来通过 <a href="https://github.com/tweenjs/tween.js" rel="noopener" target="_blank">Tween.js</a> 和 <a href="https://github.com/brehaut/color-js" rel="noopener" target="_blank">Color.js</a> 实现一个例子：</p>
<pre><code class="hljs html"><span class="hljs-tag">&lt;<span class="hljs-name">script</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"https://cdn.jsdelivr.net/npm/tween.js@16.3.4"</span>&gt;</span><span class="undefined"></span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">script</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"https://cdn.jsdelivr.net/npm/color-js@1.0.3"</span>&gt;</span><span class="undefined"></span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">div</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"example-7"</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">input</span>
    <span class="hljs-attr">v-model</span>=<span class="hljs-string">"colorQuery"</span>
    <span class="hljs-attr">v-on:keyup.enter</span>=<span class="hljs-string">"updateColor"</span>
    <span class="hljs-attr">placeholder</span>=<span class="hljs-string">"Enter a color"</span>
  &gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">button</span> <span class="hljs-attr">v-on:click</span>=<span class="hljs-string">"updateColor"</span>&gt;</span>Update<span class="hljs-tag">&lt;/<span class="hljs-name">button</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">p</span>&gt;</span>Preview:<span class="hljs-tag">&lt;/<span class="hljs-name">p</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">span</span>
    <span class="hljs-attr">v-bind:style</span>=<span class="hljs-string">"{ backgroundColor: tweenedCSSColor }"</span>
    <span class="hljs-attr">class</span>=<span class="hljs-string">"example-7-color-preview"</span>
  &gt;</span><span class="hljs-tag">&lt;/<span class="hljs-name">span</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">p</span>&gt;</span>{{ tweenedCSSColor }}<span class="hljs-tag">&lt;/<span class="hljs-name">p</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">div</span>&gt;</span></code></pre>
<pre><code class="hljs js"><span class="hljs-keyword">var</span> Color = net.brehaut.Color

<span class="hljs-keyword">new</span> Vue({
  <span class="hljs-attr">el</span>: <span class="hljs-string">'#example-7'</span>,
  <span class="hljs-attr">data</span>: {
    <span class="hljs-attr">colorQuery</span>: <span class="hljs-string">''</span>,
    <span class="hljs-attr">color</span>: {
      <span class="hljs-attr">red</span>: <span class="hljs-number">0</span>,
      <span class="hljs-attr">green</span>: <span class="hljs-number">0</span>,
      <span class="hljs-attr">blue</span>: <span class="hljs-number">0</span>,
      <span class="hljs-attr">alpha</span>: <span class="hljs-number">1</span>
    },
    <span class="hljs-attr">tweenedColor</span>: {}
  },
  <span class="hljs-attr">created</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
    <span class="hljs-keyword">this</span>.tweenedColor = <span class="hljs-built_in">Object</span>.assign({}, <span class="hljs-keyword">this</span>.color)
  },
  <span class="hljs-attr">watch</span>: {
    <span class="hljs-attr">color</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">animate</span> (<span class="hljs-params"></span>) </span>{
        <span class="hljs-keyword">if</span> (TWEEN.update()) {
          requestAnimationFrame(animate)
        }
      }

      <span class="hljs-keyword">new</span> TWEEN.Tween(<span class="hljs-keyword">this</span>.tweenedColor)
        .to(<span class="hljs-keyword">this</span>.color, <span class="hljs-number">750</span>)
        .start()

      animate()
    }
  },
  <span class="hljs-attr">computed</span>: {
    <span class="hljs-attr">tweenedCSSColor</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> Color({
        <span class="hljs-attr">red</span>: <span class="hljs-keyword">this</span>.tweenedColor.red,
        <span class="hljs-attr">green</span>: <span class="hljs-keyword">this</span>.tweenedColor.green,
        <span class="hljs-attr">blue</span>: <span class="hljs-keyword">this</span>.tweenedColor.blue,
        <span class="hljs-attr">alpha</span>: <span class="hljs-keyword">this</span>.tweenedColor.alpha
      }).toCSS()
    }
  },
  <span class="hljs-attr">methods</span>: {
    <span class="hljs-attr">updateColor</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">this</span>.color = <span class="hljs-keyword">new</span> Color(<span class="hljs-keyword">this</span>.colorQuery).toRGB()
      <span class="hljs-keyword">this</span>.colorQuery = <span class="hljs-string">''</span>
    }
  }
})</code></pre>
<pre><code class="hljs css"><span class="hljs-selector-class">.example-7-color-preview</span> {
  <span class="hljs-attribute">display</span>: inline-block;
  <span class="hljs-attribute">width</span>: <span class="hljs-number">50px</span>;
  <span class="hljs-attribute">height</span>: <span class="hljs-number">50px</span>;
}</code></pre>
<script src="https://cdn.jsdelivr.net/npm/tween.js@16.3.4"></script>
<script src="https://cdn.jsdelivr.net/npm/color-js@1.0.3"></script>
<div class="demo" id="example-7">
<input placeholder="Enter a color" v-model="colorQuery" v-on:keyup.enter="updateColor"/>
<button v-on:click="updateColor">Update</button>
<p>Preview:</p>
<span class="example-7-color-preview" v-bind:style="{ backgroundColor: tweenedCSSColor }"></span>
<p>{{ tweenedCSSColor }}</p>
</div>
<script>
var Color = net.brehaut.Color
new Vue({
  el: '#example-7',
  data: {
    colorQuery: '',
    color: {
      red: 0,
      green: 0,
      blue: 0,
      alpha: 1
    },
    tweenedColor: {}
  },
  created: function () {
    this.tweenedColor = Object.assign({}, this.color)
  },
  watch: {
    color: function () {
      function animate () {
        if (TWEEN.update()) {
          requestAnimationFrame(animate)
        }
      }

      new TWEEN.Tween(this.tweenedColor)
        .to(this.color, 750)
        .start()

      animate()
    }
  },
  computed: {
    tweenedCSSColor: function () {
      return new Color({
        red: this.tweenedColor.red,
        green: this.tweenedColor.green,
        blue: this.tweenedColor.blue,
        alpha: this.tweenedColor.alpha
      }).toCSS()
    }
  },
  methods: {
    updateColor: function () {
      this.color = new Color(this.colorQuery).toRGB()
      this.colorQuery = ''
    }
  }
})
</script>
<style>
.example-7-color-preview {
  display: inline-block;
  width: 50px;
  height: 50px;
}
</style>
<h2 id="动态状态过渡"><a class="headerlink" href="#动态状态过渡" title="动态状态过渡"></a>动态状态过渡</h2><p>就像 Vue 的过渡组件一样，数据背后状态过渡会实时更新，这对于原型设计十分有用。当你修改一些变量，即使是一个简单的 SVG 多边形也可实现很多难以想象的效果。</p>
<script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/1.18.5/TweenLite.min.js"></script>
<div class="demo" id="svg-polygon-demo">
<svg class="demo-svg" height="200" width="200">
<polygon :points="points" class="demo-polygon"></polygon>
<circle class="demo-circle" cx="100" cy="100" r="90"></circle>
</svg>
<label>Sides: {{ sides }}</label>
<input class="demo-range-input" max="500" min="3" type="range" v-model.number="sides"/>
<label>Minimum Radius: {{ minRadius }}%</label>
<input class="demo-range-input" max="90" min="0" type="range" v-model.number="minRadius"/>
<label>Update Interval: {{ updateInterval }} milliseconds</label>
<input class="demo-range-input" max="2000" min="10" type="range" v-model.number="updateInterval"/>
</div>
<script>
new Vue({
  el: '#svg-polygon-demo',
  data: function () {
    var defaultSides = 10
    var stats = Array.apply(null, { length: defaultSides })
      .map(function () { return 100 })
    return {
      stats: stats,
      points: generatePoints(stats),
      sides: defaultSides,
      minRadius: 50,
      interval: null,
      updateInterval: 500
    }
  },
  watch: {
    sides: function (newSides, oldSides) {
      var sidesDifference = newSides - oldSides
      if (sidesDifference > 0) {
        for (var i = 1; i <= sidesDifference; i++) {
          this.stats.push(this.newRandomValue())
        }
      } else {
        var absoluteSidesDifference = Math.abs(sidesDifference)
        for (var i = 1; i <= absoluteSidesDifference; i++) {
          this.stats.shift()
        }
      }
    },
    stats: function (newStats) {
      TweenLite.to(
        this.$data,
        this.updateInterval / 1000,
        { points: generatePoints(newStats) }
      )
    },
    updateInterval: function () {
      this.resetInterval()
    }
  },
  mounted: function () {
    this.resetInterval()
  },
  methods: {
    randomizeStats: function () {
      var vm = this
      this.stats = this.stats.map(function () {
        return vm.newRandomValue()
      })
    },
    newRandomValue: function () {
      return Math.ceil(this.minRadius + Math.random() * (100 - this.minRadius))
    },
    resetInterval: function () {
      var vm = this
      clearInterval(this.interval)
      this.randomizeStats()
      this.interval = setInterval(function () {
        vm.randomizeStats()
      }, this.updateInterval)
    }
  }
})

function valueToPoint (value, index, total) {
  var x     = 0
  var y     = -value * 0.9
  var angle = Math.PI * 2 / total * index
  var cos   = Math.cos(angle)
  var sin   = Math.sin(angle)
  var tx    = x * cos - y * sin + 100
  var ty    = x * sin + y * cos + 100
  return { x: tx, y: ty }
}

function generatePoints (stats) {
  var total = stats.length
  return stats.map(function (stat, index) {
    var point = valueToPoint(stat, index, total)
    return point.x + ',' + point.y
  }).join(' ')
}
</script>
<style>
.demo-svg { display: block; }
.demo-polygon { fill: #41B883; }
.demo-circle {
  fill: transparent;
  stroke: #35495E;
}
.demo-range-input {
  display: block;
  width: 100%;
  margin-bottom: 15px;
}
</style>
<p>上述 demo 背后的代码可以通过<a href="https://jsfiddle.net/chrisvfritz/65gLu2b6/" rel="noopener" target="_blank">这个 fiddle</a> 进行详阅。</p>
<h2 id="把过渡放到组件里"><a class="headerlink" href="#把过渡放到组件里" title="把过渡放到组件里"></a>把过渡放到组件里</h2><p>管理太多的状态过渡会很快的增加 Vue 实例或者组件的复杂性，幸好很多的动画可以提取到专用的子组件。<br/>我们来将之前的示例改写一下：</p>
<pre><code class="hljs html"><span class="hljs-tag">&lt;<span class="hljs-name">script</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"https://cdn.jsdelivr.net/npm/tween.js@16.3.4"</span>&gt;</span><span class="undefined"></span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>

<span class="hljs-tag">&lt;<span class="hljs-name">div</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"example-8"</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">v-model.number</span>=<span class="hljs-string">"firstNumber"</span> <span class="hljs-attr">type</span>=<span class="hljs-string">"number"</span> <span class="hljs-attr">step</span>=<span class="hljs-string">"20"</span>&gt;</span> +
  <span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">v-model.number</span>=<span class="hljs-string">"secondNumber"</span> <span class="hljs-attr">type</span>=<span class="hljs-string">"number"</span> <span class="hljs-attr">step</span>=<span class="hljs-string">"20"</span>&gt;</span> =
  {{ result }}
  <span class="hljs-tag">&lt;<span class="hljs-name">p</span>&gt;</span>
    <span class="hljs-tag">&lt;<span class="hljs-name">animated-integer</span> <span class="hljs-attr">v-bind:value</span>=<span class="hljs-string">"firstNumber"</span>&gt;</span><span class="hljs-tag">&lt;/<span class="hljs-name">animated-integer</span>&gt;</span> +
    <span class="hljs-tag">&lt;<span class="hljs-name">animated-integer</span> <span class="hljs-attr">v-bind:value</span>=<span class="hljs-string">"secondNumber"</span>&gt;</span><span class="hljs-tag">&lt;/<span class="hljs-name">animated-integer</span>&gt;</span> =
    <span class="hljs-tag">&lt;<span class="hljs-name">animated-integer</span> <span class="hljs-attr">v-bind:value</span>=<span class="hljs-string">"result"</span>&gt;</span><span class="hljs-tag">&lt;/<span class="hljs-name">animated-integer</span>&gt;</span>
  <span class="hljs-tag">&lt;/<span class="hljs-name">p</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">div</span>&gt;</span></code></pre>
<pre><code class="hljs js"><span class="hljs-comment">// 这种复杂的补间动画逻辑可以被复用</span>
<span class="hljs-comment">// 任何整数都可以执行动画</span>
<span class="hljs-comment">// 组件化使我们的界面十分清晰</span>
<span class="hljs-comment">// 可以支持更多更复杂的动态过渡</span>
<span class="hljs-comment">// 策略。</span>
Vue.component(<span class="hljs-string">'animated-integer'</span>, {
  <span class="hljs-attr">template</span>: <span class="hljs-string">'&lt;span&gt;{{ tweeningValue }}&lt;/span&gt;'</span>,
  <span class="hljs-attr">props</span>: {
    <span class="hljs-attr">value</span>: {
      <span class="hljs-attr">type</span>: <span class="hljs-built_in">Number</span>,
      <span class="hljs-attr">required</span>: <span class="hljs-literal">true</span>
    }
  },
  <span class="hljs-attr">data</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
    <span class="hljs-keyword">return</span> {
      <span class="hljs-attr">tweeningValue</span>: <span class="hljs-number">0</span>
    }
  },
  <span class="hljs-attr">watch</span>: {
    <span class="hljs-attr">value</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">newValue, oldValue</span>) </span>{
      <span class="hljs-keyword">this</span>.tween(oldValue, newValue)
    }
  },
  <span class="hljs-attr">mounted</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
    <span class="hljs-keyword">this</span>.tween(<span class="hljs-number">0</span>, <span class="hljs-keyword">this</span>.value)
  },
  <span class="hljs-attr">methods</span>: {
    <span class="hljs-attr">tween</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">startValue, endValue</span>) </span>{
      <span class="hljs-keyword">var</span> vm = <span class="hljs-keyword">this</span>
      <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">animate</span> (<span class="hljs-params"></span>) </span>{
        <span class="hljs-keyword">if</span> (TWEEN.update()) {
          requestAnimationFrame(animate)
        }
      }

      <span class="hljs-keyword">new</span> TWEEN.Tween({ <span class="hljs-attr">tweeningValue</span>: startValue })
        .to({ <span class="hljs-attr">tweeningValue</span>: endValue }, <span class="hljs-number">500</span>)
        .onUpdate(<span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
          vm.tweeningValue = <span class="hljs-keyword">this</span>.tweeningValue.toFixed(<span class="hljs-number">0</span>)
        })
        .start()

      animate()
    }
  }
})

<span class="hljs-comment">// 所有的复杂度都已经从 Vue 的主实例中移除！</span>
<span class="hljs-keyword">new</span> Vue({
  <span class="hljs-attr">el</span>: <span class="hljs-string">'#example-8'</span>,
  <span class="hljs-attr">data</span>: {
    <span class="hljs-attr">firstNumber</span>: <span class="hljs-number">20</span>,
    <span class="hljs-attr">secondNumber</span>: <span class="hljs-number">40</span>
  },
  <span class="hljs-attr">computed</span>: {
    <span class="hljs-attr">result</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-keyword">this</span>.firstNumber + <span class="hljs-keyword">this</span>.secondNumber
    }
  }
})</code></pre>
<script src="https://cdn.jsdelivr.net/npm/tween.js@16.3.4"></script>
<div class="demo" id="example-8">
<input step="20" type="number" v-model.number="firstNumber"/> +
  <input step="20" type="number" v-model.number="secondNumber"/> =
  {{ result }}
  <p>
<animated-integer v-bind:value="firstNumber"></animated-integer> +
    <animated-integer v-bind:value="secondNumber"></animated-integer> =
    <animated-integer v-bind:value="result"></animated-integer>
</p>
</div>
<script>
Vue.component('animated-integer', {
  template: '<span>{{ tweeningValue }}</span>',
  props: {
    value: {
      type: Number,
      required: true
    }
  },
  data: function () {
    return {
      tweeningValue: 0
    }
  },
  watch: {
    value: function (newValue, oldValue) {
      this.tween(oldValue, newValue)
    }
  },
  mounted: function () {
    this.tween(0, this.value)
  },
  methods: {
    tween: function (startValue, endValue) {
      var vm = this
      function animate () {
        if (TWEEN.update()) {
          requestAnimationFrame(animate)
        }
      }

      new TWEEN.Tween({ tweeningValue: startValue })
        .to({ tweeningValue: endValue }, 500)
        .onUpdate(function () {
          vm.tweeningValue = this.tweeningValue.toFixed(0)
        })
        .start()

      animate()
    }
  }
})
new Vue({
  el: '#example-8',
  data: {
    firstNumber: 20,
    secondNumber: 40
  },
  computed: {
    result: function () {
      return this.firstNumber + this.secondNumber
    }
  }
})
</script>
<p>我们能在组件中结合使用这一节讲到各种过渡策略和 Vue <a href="transitions.html">内建的过渡系统</a>。总之，对于完成各种过渡动效几乎没有阻碍。</p>
<h2 id="赋予设计以生命"><a class="headerlink" href="#赋予设计以生命" title="赋予设计以生命"></a>赋予设计以生命</h2><p>只要一个动画，就可以带来生命。不幸的是，当设计师创建图标、logo 和吉祥物的时候，他们交付的通常都是图片或静态的 SVG。所以，虽然 GitHub 的章鱼猫、Twitter 的小鸟以及其它许多 logo 类似于生灵，它们看上去实际上并不是活着的。</p>
<p>Vue 可以帮到你。因为 SVG 的本质是数据，我们只需要这些动物兴奋、思考或警戒的样例。然后 Vue 就可以辅助完成这几种状态之间的过渡动画，来制作你的欢迎页面、加载指示、以及更加带有情感的提示。</p>
<p>Sarah Drasner 展示了下面这个 demo，这个 demo 结合了时间和交互相关的状态改变：</p>
<p></p><p class="codepen" data-default-tab="result" data-embed-version="2" data-height="265" data-pen-title="Vue-controlled Wall-E" data-slug-hash="YZBGNp" data-theme-id="light" data-user="sdras">查看 <a href="https://codepen.io" rel="noopener" target="_blank">CodePen</a> 上 Sarah Drasner (<a href="https://codepen.io/sdras" rel="noopener" target="_blank">@sdras</a>) 的例子 <a href="https://codepen.io/sdras/pen/YZBGNp/" rel="noopener" target="_blank">Vue-controlled Wall-E</a>.</p><p></p>
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