如何为元素设置动画以跟随div中的鼠标移动？

Question

我正在尝试使用jQuery动画使元素遵循容器div约束内的鼠标移动。当鼠标移动时，该元素将更改为具有与其当前位置匹配的绝对位置，然后朝着鼠标的位置移动，但在div内。

不过，我似乎无法正确地实现垂直定位：元素总是高于容器，有时元素的移动方向应与容器相反（即，鼠标向下移动，元素向上移动） 。水平定位没有问题。

这里是代码：

var executed = false;
var dronePos = $("#drone").offset().top;

$("body").mousemove(function(event) {

    var x;
    var y;

    //Vertical positioning: If the mouse position is greater than or equal to the left offset of the drone container, and less than or equal to the left offset of the drone container plus the width (if it falls within the drone container)

    if (event.pageX >= $("#droneContainer").offset().left && event.pageX <= $("#droneContainer").offset().left + $("#droneContainer").width()){
        x = event.pageX;

    } else { //if it's to the left
        if (event.pageX < $("#droneContainer").offset().left){
            x = $("#droneContainer").offset().left; 
        }
        else { //if it's to the right
            x = $("#droneContainer").offset().left + $("#droneContainer").width();
        }
    }   

    //Horizontal positioning: If the mouse position is greater than or equal to the to offset of the drone container, and less than or equal to the top offset of the drone container plus the height (if it falls within the drone container)

    if (event.pageY >= $("#droneContainer").offset().top && event.pageY <= $("#droneContainer").offset().top + $("#droneContainer").height()){
        y = event.pageY - dronePos;
    } else { //if it's above
        if (event.pageY < $("#droneContainer").offset().top){
            y = $("#droneContainer").offset().top - dronePos;   
        } else { //if it's below
            y = ($("#droneContainer").offset().top + $("#droneContainer").height()) - dronePos;
        }
    }

    if (executed == false){
        executed = true;
        var position = $("#drone").position();
        $("#drone").css({top: position.top, left: position.left, position:"absolute"}); 
    }

    $("#drone").stop().animate({
        left: x, 
        top: y
    }, 800, "swing");

    dronePos = $("#drone").offset().top;

});

任何帮助，不胜感激！ 🙏

Answer 1

很难说出您的代码示例中真正出了什么问题，所以我试图制作一个更浅的版本，希望它可以完成您自己的脚本应做的事情。

我也认为，请勿使用jQuery animate。 CSS实际上已经变得非常强大，可以为您完成很多繁重的工作。

我希望这对您有所帮助。如有任何疑问，请通知我。

var $container = $('.container');
var $drone = $('.drone');
var droneCenter = {
  x: $drone.width() / 2,
  y: $drone.height() / 2
};

$container.on('mousemove', function(event) {
  $drone.css('transform', `translate3d(${event.offsetX - droneCenter.x}px, ${event.offsetY - droneCenter.y}px, 0)`);
});

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: grid;
  align-items: safe center;
  justify-content: safe center;
}

.wrapper {
  width: 100vw;
  height: 100vh;
  max-width: 1000px;
  max-height: 1000px;
  padding: 15px;
}

.container {
  position: relative;
  width: 100%;
  height: 100%;
  background-color: #f7f7f7;
  border: 1px solid #f0f0f0;
  border-radius: 5px;
  overflow: hidden;
}

.drone {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 25px;
  height: 25px;
  background-color: red;
  border-radius: 50%;
  transition: transform 800ms ease-out;
  will-change: transform;
  pointer-events: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="wrapper">
  <div class="container">
    <div class="drone"></div>
  </div>
</div>