vue3封装放大镜组件

组件基础结构

结尾有完整代码可直接复制使用

• 目的：封装图片预览组件，实现鼠标悬停切换效果

• 落地代码：

  <template>
    <div class="goods-image">
      <div class="middle">
        <img :src="images[currIndex]" alt="">
      </div>
      <ul class="small">
        <li v-for="(img,i) in images" :key="img" :class="{active:i===currIndex}">
          <img @mouseenter="currIndex=i" :src="img" alt="">
        </li>
      </ul>
    </div>
  </template>
  <script>
  import { ref } from 'vue'
  export default {
    name: 'GoodsImage',
    props: {
      images: {
        type: Array,
        default: () => []
      }
    },
    setup (props) {
      const currIndex = ref(0)
      return { currIndex }
    }
  }
  </script>
  <style scoped lang="less">
  .goods-image {
    width: 480px;
    height: 400px;
    position: relative;
    display: flex;
    .middle {
      width: 400px;
      height: 400px;
      background: #f5f5f5;
    }
    .small {
      width: 80px;
      li {
        width: 68px;
        height: 68px;
        margin-left: 12px;
        margin-bottom: 15px;
        cursor: pointer;
        &:hover,&.active {
          border: 2px solid @xtxColor;
        }
      }
    }
  }
  </style>
  复制代码

图片放大镜

• 目的：实现图片放大镜功能

• 步骤：

  • 首先准备大图容器和遮罩容器
  • 然后使用@vueuse/core的useMouseInElement方法获取基于元素的偏移量
  • 计算出 遮罩容器定位与大容器背景定位 暴露出数据给模板使用

• 落地代码：

  <template>
    <div class="goods-image">
  +     // 实现右侧大图布局效果（背景图放大4倍）
  +    <div class="large" :style="[{backgroundImage:`url(${images[currIndex]})`}]"></div>
      <div class="middle">
        <img :src="https://juejin.cn/post/images[currIndex]" >
  +      // 准备待移动的遮罩容器
  +     <div class="layer"></div>
      </div>
      <ul class="small">
        <li v-for="(img,i) in images" :key="img" :class="{active:i===currIndex}">
          <img @mouseenter="currIndex=i" :src="https://juejin.cn/post/img" >
        </li>
      </ul>
    </div>
  </template>
  <script>
  import { ref } from 'vue'
  export default {
    name: 'GoodsImage',
    props: {
      images: {
        type: Array,
        default: () => []
      }
    },
    setup (props) {
      const currIndex = ref(0)
      return { currIndex }
    }
  }
  </script>
  <style scoped lang="less">
  .goods-image {
    width: 480px;
    height: 400px;
    position: relative;
    display: flex;
  +  z-index: 500;
  +    // 右侧大图样式
  +  .large {
  +    position: absolute;
  +    top: 0;
  +    left: 412px;
  +    width: 400px;
  +    height: 400px;
  +    box-shadow: 0 0 10px rgba(0,0,0,0.1);
  +    background-repeat: no-repeat;
  +    background-size: 800px 800px;
  +    background-color: #f8f8f8;
  +  }
    .middle {
      width: 400px;
      height: 400px;
      background: #f5f5f5;
  +    position: relative;
  +    cursor: move;
  +    // 遮罩样式
  +    .layer {
  +      width: 200px;
  +      height: 200px;
  +      background: rgba(0,0,0,.2);
  +      left: 0;
  +      top: 0;
  +      position: absolute;
  +    }
    }
    .small {
      width: 80px;
      li {
        width: 68px;
        height: 68px;
        margin-left: 12px;
        margin-bottom: 15px;
        cursor: pointer;
        &:hover,&.active {
          border: 2px solid @xtxColor;
        }
      }
    }
  }
  </style>
  复制代码

安装vueuse

• npm i @vueuse/core@5.3.0

  目前5.3.0版本相对稳定

• vueuse提供的监听进入指定范围方法的基本使用

  import { useMouseInElement } from '@vueuse/core'
  const { elementX, elementY, isOutside } = useMouseInElement(target)
  复制代码

  方法的参数target表示被监听的DOM对象；返回值elementX, elementY表示被监听的DOM的左上角的位置信息left和top；isOutside表示是否在DOM的范围内，true表示在范围之外。false表示范围内。

功能实现

<div v-if="isShow" class="large" :style="[{ backgroundImage: `url(${images[currIndex]})` }, bgPosition]"></div>
<div class="middle" ref="target">
   <img :src="images[currIndex]" alt="" />
   <div class="layer" v-if="isShow" :style="[position]"></div>
</div>

setup () {
// 被监听的区域
const target = ref(null)
// 控制遮罩层和预览图的显示和隐藏
const isShow = ref(false)
// 定义遮罩的坐标
const position = reactive({
      left: 0,
      top: 0
})
// 右侧预览大图的坐标
const bgPosition = reactive({
      backgroundPositionX: 0,
      backgroundPositionY: 0
})

return { position, bgPosition, target, isShow }
}
复制代码

const { elementX, elementY, isOutside } = useMouseInElement(target)
  // 基于侦听器侦听值的变化
  watch([elementX, elementY, isOutside], () => {
    // 通过标志位控制显示和隐藏
    isShow.value = !isOutside.value
    if (isOutside.value) return
    // X方向坐标范围控制
    if (elementX.value < 100) {
      // 左侧
      position.left = 0
    } else if (elementX.value > 300) {
      // 右侧
      position.left = 200
    } else {
      // 中间
      position.left = elementX.value - 100
    }
    // Y方向坐标范围控制
    if (elementY.value < 100) {
      position.top = 0
    } else if (elementY.value > 300) {
      position.top = 200
    } else {
      position.top = elementY.value - 100
    }
    // 计算预览大图的移动的距离
    bgPosition.backgroundPositionX = -position.left * 2 + 'px'
    bgPosition.backgroundPositionY = -position.top * 2 + 'px'
    // 计算遮罩层的位置
    position.left = position.left + 'px'
    position.top = position.top + 'px'
  })
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完整代码

<template>
  <div class="goods-image">
    <div v-if="isShow" class="large" :style="[{ backgroundImage: `url(${images[currIndex]})` }, bgPosition]"></div>
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="" />
      <div class="layer" v-if="isShow" :style="[position]"></div>
    </div>
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex = i" :src="img" alt="" />
      </li>
    </ul>
  </div>
</template>
<script>
import { ref, watch, reactive } from 'vue'
import { useMouseInElement } from '@vueuse/core'
export default {
  name: 'GoodsImage',
  props: {
    images: {
      type: Array,
      default: () => []
    }
  },
  setup (props) {
    const currIndex = ref(0)
    const target = ref(null)
    const isShow = ref(false)
    const position = reactive({
      left: 0,
      top: 0
    })
    const bgPosition = reactive({
      backgroundPositionX: 0,
      backgroundPositionY: 0
    })
    const { elementX, elementY, isOutside } = useMouseInElement(target)
    watch([elementX, elementY, isOutside], () => {
      isShow.value = !isOutside.value
      if (isOutside.value) return
      if (elementX.value <= 100) {
        position.left = 0
      } else if (elementX.value >= 300) {
        position.left = 200
      } else {
        position.left = elementX.value - 100
      }
      if (elementY.value <= 100) {
        position.top = 0
      } else if (elementY.value >= 300) {
        position.top = 200
      } else {
        position.top = elementY.value - 100
      }
      bgPosition.backgroundPositionX = -position.left * 2 + 'px'
      bgPosition.backgroundPositionY = -position.top * 2 + 'px'
      position.left += 'px'
      position.top += 'px'
    })
    return { currIndex, target, isShow, position, bgPosition }
  }
}
</script>
<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;
  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }
  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
     position: relative;
    cursor: move;
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0,0,0,.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>
复制代码