Vue realizes the magnifying glass effect of Taobao products

Implementation principle:

The two boxes move synchronously through mapping to achieve the effect of moving a magnifying glass

important point:

The area of ​​the mask layer/the area of ​​the box == the area of ​​the large image display box/the area of ​​the large image, it must be in equal proportions, and the style is strictly controlled

 Movement distance of the occlusion layer/movement distance of the large image = maximum movement distance of the occlusion layer/maximum movement distance of the large image movement distance of the large image =
 movement distance of the occlusion layer * maximum movement distance of the large image/maximum movement distance of the occlusion layer

Effect:

code:

<template>
  <div class="fdj" @mousemove="mousemove">
        <div class="small" ref="small">
            <img src="../assets/copy李茜.jpg" alt="" />
            <div class="mask" :style="{'left':left + 'px','top':top + 'px',}" ref="mask"></div>
        </div>
        <div class="big" ref="big">
            <img ref="bigimg" src="../assets/copy李茜.jpg" alt=""  :style="{'left':imgX + 'px','top':imgY + 'px',}"/>
        </div>
    </div>
</template>

<script>
export default {
  data () {
    return {
      top:'',
      left:'',
      imgX:'',
      imgY:'',
    }
  },
  methods: {
    mousemove(e){
      let small = this.$refs.small
      let mask = this.$refs.mask
      let big = this.$refs.big
      let bigimg = this.$refs.bigimg
      
      // 第一步获取鼠标中点位置
      let maskX =  e.pageX - small.offsetLeft
      let maskY = e.pageY - small.offsetTop

      // 让鼠标出现在mask的中心点
      maskX = maskX - mask.offsetWidth / 2;
      maskY = maskY - mask.offsetHeight / 2;


      // 把mask限制到box中
      maskX = maskX < 0 ? 0 : maskX;
      maskY = maskY < 0 ? 0 : maskY;
     
      maskX = maskX > small.offsetWidth - mask.offsetWidth ? small.offsetWidth - mask.offsetWidth : maskX;
      maskY = maskY > small.offsetHeight - mask.offsetHeight ? small.offsetHeight - mask.offsetHeight : maskY;

      //遮挡层的移动距离/大图的移动距离=遮挡层的最大移动距离/大图的最大移动距离
      //大图的移动距离=遮挡层的移动距离*大图的最大移动距离/遮挡层的最大移动距离
      
      // 注意：
      // 遮罩层的面积/盒子的面积 == 大图展示盒子的面积/大图图片的面积
      // 一定要是等比例的才行严格控制样式
      
      let bigImgX = maskX * (big.offsetWidth - bigimg.offsetWidth) / (small.offsetWidth - mask.offsetWidth);
      let bigImgY = maskY * (big.offsetHeight - bigimg.offsetHeight) / (small.offsetHeight - mask.offsetHeight)

      this.left = maskX
      this.top = maskY
      this.imgX = bigImgX
      this.imgY = bigImgY 
    }
  }
}
</script>

<style>
/* 新建的项目  去一下默认样式 */
 body,html{ 
   padding: 0;
   margin: 0;
 }
</style>
<style leng="less" scoped>
.small {
    width: 400px;
    height: 400px;
    position: relative;
  }
.small img {
  width: 100%;
  height: 100%;
}
.big {
      width: 400px;
      height: 400px;
      position: absolute;
      top: 0;
      left: 410px;
      overflow: hidden;
  }
  .big img {
      position: absolute;
      width: 800px;
      height: 800px;
      left:0;
      top:0;
  }

  .mask {
      width: 200px;
      height: 200px;
      background: rgba(255, 255, 0, 0.4);
      position: absolute;
      top: 0px;
      left: 0px;
      cursor: move;
  }
</style>