一、需求描述：

在使用Vue进行项目开发时，需要把产品的照片进行放大展示。方法图片随鼠标在一定范围内，移动而放大。

二、需求分析：

三、解决方案：

<template>
  <div class="spec-preview">
  //图片地址
    <img :src="ImageList.imgUrl" />
    //定义鼠标事件
    <div class="event" @mousemove="handler"></div>
    //定义放大后的图样式
    <div class="big">
    //放大后的图的原始图片
      <img :src="ImageList.imgUrl" ref="big" />
    </div>
    <!-- 遮罩层 -->
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
export default {
  name: "Zoom",
  props: ["skuImageList"],
  data() {
    return {
      currentIndex: 0,
    };
  },
  computed: {
    ImageList() {
      return this.skuImageList[this.currentIndex] || {};
    },
  },
  mounted() {
    //全局事件总线获取兄弟组件传递过来的索引值
    this.$bus.$on("getIndex", (index) => {
      this.currentIndex = index;
    });
  },
  methods: {
  //这里是放大方法的主要处理逻辑
    handler(event) {
      let mask = this.$refs.mask;
      let big = this.$refs.big;
      let left = event.offsetX - mask.offsetWidth / 2;
      let top = event.offsetY - mask.offsetHeight / 2;
      //约束范围
      if (left <= 0) left = 0;
      if (left >= mask.offsetWidth) left = mask.offsetWidth;
      if (top <= 0) top = 0;
      if (top >= mask.offsetHeight) top = mask.offsetHeight;
      mask.style.left = left + "px";
      mask.style.top = top + "px";
      big.style.left = -2 * left + "px";
      big.style.top = -2 * top + "px";
      console.log(left);
    },
  },
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(171, 250, 171, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>