FLIP动画 概述

什么是FLIP动画技术?FLIP其实是一种思路, 一种方法论, 并不是具体指代某个技术.
FLIP, 具体意义如下:

  • F first 参加过渡元素的初始状态
  • L last 元素的终止状态
  • I invert flip的核心, 通过first和last计算, 然后翻转这个过程
  • P play 启用tansition, 移除你invert的改变,这时候动画会按预期完成

实践操作,利用FLIP思路完成过渡动画

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .row span {
      padding: 0 5px;
      display: inline-block;
    }
  </style>
</head>

<body>
  <div class="row" id="row">

  </div>

  <button onclick="randomFLIP()">点击打乱</button>
</body>
<script>
  const render = (arr) => {
    document.getElementById('row').innerHTML = arr.map(v => `<span id="k${v}">${v}</span>`).join('')
  }
  const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
  render(arr)

  // 随机打乱
  function shuffle(arr) {
    for (var i = arr.length - 1; i >= 0; i--) {
      var randomIndex = Math.floor(Math.random() * (i + 1));
      var itemAtIndex = arr[randomIndex];
      arr[randomIndex] = arr[i];
      arr[i] = itemAtIndex;
    }
    return arr;
  }

  // FLIP动画函数
  function randomFLIP() {
    const randomArr = shuffle(arr)
    // First
    const firstRect = (() => {
      const result = {}
      arr.map(v => {
        result[`k${v}`] = document.getElementById(`k${v}`).getBoundingClientRect()
      })
      return result
    })()

    render(randomArr)

    // Last
    const lastRect = (() => {
      const result = {}
      randomArr.map(v => {
        result[`k${v}`] = document.getElementById(`k${v}`).getBoundingClientRect()
      })
      return result
    })()

    // invert

    arr.forEach(v => {
      const first = firstRect[`k${v}`]
      const last = lastRect[`k${v}`]
      const deltaX = first.left - last.left;
      const deltaY = first.top - last.top;

      document.getElementById(`k${v}`).style = `transform: translate(${deltaX}px, ${deltaY}px);`
      requestAnimationFrame(function () {
        // Play 去掉translate, 加上动画
        document.getElementById(`k${v}`).style = 'transition: all 1s'
        document.getElementById(`k${v}`).style.transform = ''
      })
    })
  }
</script>

</html>

在线预览

http://jsrun.net/ZIVKp


陈东民
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