Js<判断鼠标移入移出方向>

2021-03-31 16-59-22.gif

主要通过 Math.atan2 来判断鼠标移入移出的方向来添加不同的 class动画属性 ,进而实现的效果
知识点:
1..getBoundingClientRect()属性;

  1. Math.atan2 ;

3.addEventListener鼠标监听的, 移入mouseenter 移出 mouseleave;

具体详情请看代码注释部分~

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

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title></title>
  <style>
    body {
      margin: 0;
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
    }

    #warp {
      width: 200px;
      height: 200px;
      background: rgb(109, 47, 255);
      display: flex;
      justify-content: center;
      align-items: center;
      color: white;
      position: relative;
      overflow: hidden;
    }

    .text {
      position: relative;
      z-index: 5;
    }

    .cover {
      width: 100%;
      height: 100%;
      position: absolute;
      z-index: 1;
      background: rgba(0, 0, 0, 0.397);
      opacity: 0;
      pointer-events: none;
    }

    /* 进入动画 */
    .cover.topEnter {
      opacity: 1;
      animation: topEnter .3s ease both 1;
    }

    .cover.rightEnter {
      opacity: 1;
      animation: rightEnter .3s ease both 1;
    }

    .cover.bottomEnter {
      opacity: 1;
      animation: bottomEnter .3s ease both 1;
    }

    .cover.leftEnter {
      opacity: 1;
      animation: leftEnter .3s ease both 1;
    }

    /* 移出动画 */
    .cover.topLeave {
      opacity: 1;
      animation: topLeave .3s ease both 1;
    }

    .cover.rightLeave {
      opacity: 1;
      animation: rightLeave .3s ease both 1;
    }

    .cover.bottomLeave {
      opacity: 1;
      animation: bottomLeave .3s ease both 1;
    }

    .cover.leftLeave {
      opacity: 1;
      animation: leftLeave .3s ease both 1;
    }

    /* 进入动画 */
    @keyframes topEnter {
      0% {
        transform: translateY(-100%);
      }

      100% {
        transform: translateY(0);
      }
    }

    @keyframes rightEnter {
      0% {
        transform: translateX(100%);
      }

      100% {
        transform: translateX(0);
      }
    }

    @keyframes bottomEnter {
      0% {
        transform: translateY(100%);
      }

      100% {
        transform: translateY(0);
      }
    }

    @keyframes leftEnter {
      0% {
        transform: translateX(-100%);
      }

      100% {
        transform: translateX(0);
      }
    }

    /* 移出动画 */
    @keyframes topLeave {
      0% {
        transform: translateY(0);
      }

      100% {
        transform: translateY(-100%);
      }
    }

    @keyframes rightLeave {
      0% {
        transform: translateX(0);
      }

      100% {
        transform: translateX(100%);
      }
    }

    @keyframes bottomLeave {
      0% {
        transform: translateY(0);
      }

      100% {
        transform: translateY(100%);
      }
    }

    @keyframes leftLeave {
      0% {
        transform: translateX(0);
      }

      100% {
        transform: translateX(-100%);
      }
    }
  </style>
</head>

<body>
  <div id="warp">
    <span class="text">MOVE</span>
    <div class="cover"></div>
  </div>
</body>
<script>
  // 获取容器
  let warp = document.getElementById('warp')
  // 获取遮罩层
  let cover = document.querySelector('.cover')
  let text = document.querySelector('.text')
  // 获取容器的相关属性
  let _this = warp.getBoundingClientRect();
  let w = _this.width
  let h = _this.height
  let offsetLeft = _this.left
  let offsetTop = _this.top
  // 定义一个方向的数组
  let dirName = new Array('top', 'right', 'bottom', 'left');

  // 监听鼠标进入容器时
  warp.addEventListener('mouseenter', function (e) {
    let x = (e.pageX - offsetLeft - (w / 2)) * (w > h ? (h / w) : 1);
    let y = (e.pageY - offsetTop - (h / 2)) * (h > w ? (w / h) : 1);
    // 用来获取移入的方位
    // 通过Math.atan2 计算角度 https://www.jianshu.com/p/9817e267925a
    let direction = Math.round((((Math.atan2(y, x) * (180 / Math.PI)) + 180) / 90) + 3) % 4;
    let dirText = dirName[direction];
    text.innerHTML = dirText + ' Enter' //文字修改
    // 通过移入方位,添加移入动画class
    switch (dirText) {
      case 'top':
        cover.setAttribute("class", "cover topEnter");
        break;
      case 'right':
        cover.setAttribute("class", "cover rightEnter");
        break;
      case 'bottom':
        cover.setAttribute("class", "cover bottomEnter");
        break;
      case 'left':
        cover.setAttribute("class", "cover leftEnter");
        break;
      default:
        break;
    }
  })
  // 监听鼠标移出容器时
  warp.addEventListener('mouseleave', function (e) {
    let x = (e.pageX - offsetLeft - (w / 2)) * (w > h ? (h / w) : 1);
    let y = (e.pageY - offsetTop - (h / 2)) * (h > w ? (w / h) : 1);
    // 用来获取移入的方位
    // 通过Math.atan2 计算角度 https://www.jianshu.com/p/9817e267925a
    let direction = Math.round((((Math.atan2(y, x) * (180 / Math.PI)) + 180) / 90) + 3) % 4;
    let dirText = dirName[direction];
    text.innerHTML = dirText + ' Leave';//文字修改
    // 通过移入方位,添加移出动画class
    switch (dirText) {
      case 'top':
        cover.setAttribute("class", "cover topLeave");
        break;
      case 'right':
        cover.setAttribute("class", "cover rightLeave");
        break;
      case 'bottom':
        cover.setAttribute("class", "cover bottomLeave");
        break;
      case 'left':
        cover.setAttribute("class", "cover leftLeave");
        break;
      default:
        break;
    }
  })
</script>

</html>

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