animation - CSS(层叠样式表) 编辑

CSS animation 属性是 animation-nameanimation-duration, animation-timing-functionanimation-delayanimation-iteration-countanimation-directionanimation-fill-modeanimation-play-state 属性的一个简写属性形式。

/* @keyframes duration | timing-function | delay |
   iteration-count | direction | fill-mode | play-state | name */
animation: 3s ease-in 1s 2 reverse both paused slidein;

/* @keyframes duration | timing-function | delay | name */
animation: 3s linear 1s slidein;

/* @keyframes duration | name */
animation: 3s slidein;
<div class="grid">
  <div class="col">
    <div class="note">
      Given the following animation:
      <pre>@keyframes slidein {
  from { transform: scaleX(0); }
  to   { transform: scaleX(1); }
}</pre>
    </div>
    <div class="row">
      <div class="cell">
        <button class="play" title="PLAY"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s ease-in 1s 2 reverse both paused slidein;</div>
        <div class="animation a1"></div>
      </div>
    </div>
    <div class="row">
      <div class="cell">
        <button class="pause" title="PAUSE"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s linear 1s slidein;</div>
        <div class="animation a2"></div>
      </div>
    </div>
    <div class="row">
      <div class="cell">
        <button class="pause" title="PAUSE"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s slidein;</div>
        <div class="animation a3"></div>
      </div>
    </div>
  </div>
</div>
html,body {
  height: 100%;
  box-sizing: border-box;
}

pre { margin-bottom: 0; }
svg { width: 1.5em; height: 1.5em; }

button {
  width: 27px;
  height: 27px;
  background-size: 16px;
  background-position: center;
  background-repeat: no-repeat;
  border-radius: 3px;
  cursor: pointer;
}

button.play {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#play');
}

button.pause {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#pause');
}

button.restart {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#restart');
}

.grid {
  width: 100%;
  height: 100%;
  display: flex;
  background: #EEE;
  font: 1em monospace;
}

.row {
  display: flex;
  flex: 1 auto;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: space-between;
}

.col {
  display: flex;
  flex: 1 auto;
  flex-direction: column;
}

.cell {
  box-sizing: border-box;
  margin: .5em;
  padding: 0;
  background-color: #FFF;
  overflow: hidden;
  text-align: left;
}

.flx {
  flex: 1 0;
}

.note {
  background: #fff3d4;
  padding: 1em;
  margin: .5em;
  font: .8em sans-serif;
  text-align: left;
  flex: none;
}

.overlay { padding: .5em; }

@keyframes slidein {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

.a1 { animation: 3s ease-in 1s 2 reverse both paused slidein; }
.a2 { animation: 3s linear 1s slidein; }
.a3 { animation: 3s slidein; }

.animation {
  background: #3F87A6;
  width: 100%;
  height: calc(100% - 1.5em);
  transform-origin: left center;
}
window.addEventListener('load', function () {
  var ANIMATION = Array.from(document.querySelectorAll('.animation'));
  var BUTTON    = Array.from(document.querySelectorAll('button'));

  function toggleButton (btn, type) {
    btn.classList.remove('play', 'pause', 'restart');
    btn.classList.add(type);
    btn.title = type.toUpperCase(type);
  }

  function playPause (i) {
    var btn  = BUTTON[i];
    var anim = ANIMATION[i];

    if (btn.classList.contains('play')) {
      anim.style.animationPlayState = 'running';
      toggleButton(btn, 'pause');
    } else if (btn.classList.contains('pause')) {
      anim.style.animationPlayState = 'paused';
      toggleButton(btn, 'play');
    } else {
      anim.classList.remove('a' + (i + 1));
      setTimeout(function () {
        toggleButton(btn, i === 0 ? 'play' : 'pause');
        anim.style.animationPlayState = '';
        anim.classList.add('a' + (i + 1));
      }, 100)
    }
  }

  ANIMATION.forEach(function (node, index) {
    node.addEventListener('animationstart', function () { toggleButton(BUTTON[index], 'pause');   });
    node.addEventListener('animationend',   function () { toggleButton(BUTTON[index], 'restart'); });
  });

  BUTTON.forEach(function (btn, index) {
    btn.addEventListener('click', function () { playPause(index); });
  });
})

哪些属性是可动画的?值得注意的是,此描述也适用于CSS变换

初始值as each of the properties of the shorthand:
适用元素all elements, ::before and ::after pseudo-elements
是否是继承属性
计算值as each of the properties of the shorthand:
Animation typediscrete

语法

animation 属性用来指定一组或多组动画,每组之间用逗号相隔。

每组动画规定的属性如下:

每个动画定义中的属性值的顺序很重要:可以被解析为 <time> 的第一个值被分配给animation-duration, 第二个分配给 animation-delay

每个动画定义中的值的顺序,对于区分 animation-name 值与其他关键字也很重要。解析时,对于除 animation-name 之外的有效的关键字,必须被前面的简写中没有找到值的属性所接受。此外,在序列化时,animation-name 与以及其他属性值做区分等情况下,必须输出其他属性的默认值。

Values

<single-animation-iteration-count>
动画播放的次数。该值必须是animation-iteration-count可用的值之一。
<single-animation-direction>
动画播放的方向。该值必须是animation-direction可用的值之一。
<single-animation-fill-mode>
确定动画在执行之前和之后这两个阶段应用的样式。该值必须是animation-fill-mode可用的值之一。
<single-animation-play-state>
确定动画是否正在播放。该值必须是animation-play-state中可用的值之一。

语法

<single-animation>#

where
<single-animation> = <time> || <timing-function> || <time> || <single-animation-iteration-count> || <single-animation-direction> || <single-animation-fill-mode> || <single-animation-play-state> || [ none | <keyframes-name> ]

where
<timing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function>
<single-animation-iteration-count> = infinite | <number>
<single-animation-direction> = normal | reverse | alternate | alternate-reverse
<single-animation-fill-mode> = none | forwards | backwards | both
<single-animation-play-state> = running | paused
<keyframes-name> = <custom-ident> | <string>

where
<cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number <a href="/wiki/zh-CN/docs/CSS/Value_definition_syntax" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>, <number <a href="/wiki/zh-CN/docs/CSS/Value_definition_syntax" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>)
<step-timing-function> = step-start | step-end | steps(<integer>[, <step-position>]?)

where
<step-position> = jump-start | jump-end | jump-none | jump-both | start | end

范例

赛隆人之眼(赛隆人是一个虚构的生化人种族,出自科幻电视系列剧星际大争霸系列)

<div class="view_port">
  <div class="polling_message">
    Listening for dispatches
  </div>
  <div class="cylon_eye"></div>
</div>
.polling_message {
  color: white;
  float: left;
  margin-right: 2%;
}

.view_port {
  background-color: black;
  height: 25px;
  width: 100%;
  overflow: hidden;
}

.cylon_eye {
  background-color: red;
  background-image: linear-gradient(to right,
      rgba(0, 0, 0, .9) 25%,
      rgba(0, 0, 0, .1) 50%,
      rgba(0, 0, 0, .9) 75%);
  color: white;
  height: 100%;
  width: 20%;

  -webkit-animation: 4s linear 0s infinite alternate move_eye;
          animation: 4s linear 0s infinite alternate move_eye;
}

@-webkit-keyframes move_eye { from { margin-left: -20%; } to { margin-left: 100%; }  }
        @keyframes move_eye { from { margin-left: -20%; } to { margin-left: 100%; }  }

更多示例请参阅使用CSS动画

潜在的问题

眨眼和闪烁的动画对于有认知问题的人来说是有问题的,比如注意力缺陷多动障碍(ADHD)。此外,某些动画效果可以触发前庭神经紊乱、癫痫、偏头痛和暗点敏感性。

考虑提供一种暂停或禁用动画的机制,以及使用 Reduced Motion Media Query(简约运动媒体查询),为那些表示不喜欢动画的用户创建一个良好的体验。

规范

SpecificationStatusComment
CSS Animations
animation
Working DraftInitial definition

浏览器兼容性

BCD tables only load in the browser

Quantum CSS notes

  • Gecko有一个bug,当你在屏幕上对屏幕外的元素使用带有指定延时的动画时,Gecko不会在某些平台上重绘,例如Windows bug 1383239。这个问题已经在Firefox新的并行CSS引擎(也称为Quantum CSS 或者 Stylo,计划在Firefox 57中发布)中得到了解决。
  • 另外一个Gecko bug,当我们激活<details>元素的动画效果时,即使通过 open 属性也不能将其展示(bug 1382124)。Quantum CSS会将其修复了。
  • 另一个bug是,由于动画使用的是em单位,所以即使我们改变父元素的font-size属性也不会影响该动画元素(bug 1254424),而它们原本应该受到影响。Quantum CSS会将其修复了。

更多

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