js css3 固定点拖拽旋转

一、直接上效果图：

 

然后是代码：

一共两种实现方式：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
  <style>
    .box {
      width: 200px;
      height:100px;
      background: #cccccc;
      position: absolute;
      top: 30%;
      left: 40%;
      transform-origin: 50% 50% 0;
    }
  </style>
</head>
<body>
  <div id="box" class="box"></div>

  <script>

    // 第一种
    var isMove = false;
    $('#box').mousedown(function (event) {
      const element = event.target;
      const rect = element.getBoundingClientRect();
      element.dataset.centerX = rect.left + rect.width / 2;
      element.dataset.centerY = rect.top + rect.height / 2;
      element.dataset.angle = getDragAngle(event);
      isMove = true;
    });

    $('#box').mousemove(function (event) {
      if (isMove) {
        var angle = getDragAngle(event);
        event.target.style.transform = 'rotate(' + angle + 'rad)';
      }
    });

    $('#box').mouseup(function (event) {
      isMove = false;
      event.target.dataset.angle = getDragAngle(event);
    });

    function getDragAngle(event) {
      var element = event.target;
      var startAngle = parseFloat(element.dataset.angle) || 0;
      var center = {
        x: parseFloat(element.dataset.centerX) || 0,
        y: parseFloat(element.dataset.centerY) || 0,
      };
      var angle = Math.atan2(center.y - event.clientY, center.x - event.clientX);
      return angle - startAngle;
    }
//     第二种
//     $(document).on('mousemove',function(e){
//       var x = e.clientX;
//       var y = e.clientY;
//       var origin = {x:950,y:190} // 先手动指定当前中心点，也可以根据当前元素的left+width/2 的到x  top+height/2 得到y值

//       // 计算出当前鼠标相对于元素中心点的坐标
//       x = x - origin.x; // 因为x大于origin.x 是在y轴右边，直接减就行了
//       y = origin.y - y;// 但是y如果要在x轴上方，它是比origin.y要小的，所以这里就需要反过来

//        // 然后计算就可以了
//       var ele = document.getElementById('box')
//       var deg = Math.atan2(y, x) / Math.PI * 180;
//       ele.style.transform = 'rotate('+ -deg +'deg)'
// });

    </script>

</body>
</html>

 

二、固定4个顶点

代码：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>
  <style>
    * {
      user-select: none;
    }
    .box {
      width: 200px;
      height:100px;
      background: #cccccc;
      position: relative;
      top: 30%;
      left: 40%;
      transform-origin: 50% 50% 0;
      margin-top: 15%;
    }

    .dot {
      position: absolute;
      width: 20px;
      height: 20px;
      background-color: #f60;
    }

    .dot1 {
      top: -10px;
      left: -10px;
    }

    .dot2 {
      top: -10px;
      right: -10px;
    }

    .dot3 {
      bottom: -10px;
      right: -10px;
    }

    .dot4 {
      bottom: -10px;
      left: -10px;
    }
  </style>
</head>
<body>
  <div id="box" class="box">
    <div class="dot dot1"></div>
    <div class="dot dot2"></div>
    <div class="dot dot3"></div>
    <div class="dot dot4"></div>
  </div>

  <script>

    // 第一种
    var isMove = false;
    $('.dot').mousedown(function (event) {
      const element = $('#box')[0]
      const rect = element.getBoundingClientRect();
      element.dataset.centerX = rect.left + rect.width / 2;
      element.dataset.centerY = rect.top + rect.height / 2;
      element.dataset.angle = getDragAngle(event);
      isMove = true;
    });

    $(document).mousemove(function (event) {
      if (isMove) {
        var angle = getDragAngle(event);
        $('#box')[0].style.transform = 'rotate(' + angle + 'rad)';
      }
    });

    $(document).mouseup(function (event) {
　　　 if (isMove) {
      　　isMove = false;
      　　$('#box')[0].dataset.angle = getDragAngle(event);
  　　 }
    });

    function getDragAngle(event) {
      var element = $('#box')[0];
      var startAngle = parseFloat(element.dataset.angle) || 0;
      var center = {
        x: parseFloat(element.dataset.centerX) || 0,
        y: parseFloat(element.dataset.centerY) || 0,
      };
      var angle = Math.atan2(center.y - event.clientY, center.x - event.clientX);
      return angle - startAngle;
    }
    </script>

</body>
</html>

 

posted on 2019-09-03 16:47  allenpxt  阅读(3052)  评论(0)  编辑  收藏  举报

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