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Vue实现悬浮图片弹出大图预览弹窗，弹窗顶部与图片顶部平齐

需求背景

当前项目内某页面左侧展示图片列表，图片列表展示的均为小图。需求希望鼠标移动到对应图片时，右侧出现大图预览弹窗，且该弹窗顶部需与图片顶部平齐。同时弹窗要在页面中展示完全，不能超出窗口高度导致被遮挡

核心实现

1.获取悬浮图片的位置信息

<div class="image_item" v-for="(item, index) in imgList" :key="index"><img:src="item"class="img"@mouseenter="e => handlePreview(e, item)"@mouseleave="preview.show = false"/>
</div>

// 获取当前图片顶部与视口顶部的距离top和底部的距离bottom
const handlePreview = (e, url) => {const targetRect = e.target.getBoundingClientRect()preview.bottom = window.innerHeight - targetRect.toppreview.top = targetRect.toppreview.url = urlpreview.show = true
}

2.动态计算大图预览弹窗位置

<!-- 样式绑定计算属性，根据悬浮图片位置变化 -->
<div class="module_view" v-show="preview.show" :style="previewStyle"><img :src="preview.url" class="img" />
</div>

const previewStyle = computed(() => {// 弹窗实际高度const previewHeight = 538const container = listRef.value// 容器与视口顶部距离const containerTop = container ? container.getBoundingClientRect().top : 0const previewTop = preview.topconst previewBottom = preview.bottom// 弹窗顶部与容器顶部的距离let top = previewTop - containerToplet bottom = previewBottom - previewHeight// 判断弹窗顶部与视口底部的距离是否能容纳整个弹窗if (bottom < 0) {// 无法容纳时，减小弹窗顶部距离容器顶部的距离从而抬升弹窗// 还需判断抬升后弹窗顶部与视口顶部是否仍大于0，否则设置为置顶距离，即负的容器与视口顶部距离top = previewTop + bottom > 0 ? top + bottom : 0 - containerTop}return {top: top + 'px'}
})

完整代码

<!-- 实现图片悬浮右侧展开预览大图弹窗功能，弹窗顶部与图片顶部平齐 -->
<template><div class="image_view"><div class="image_list" ref="listRef"><div class="image_item" v-for="(item, index) in imgList" :key="index"><img:src="item"class="img"@mouseenter="e => handlePreview(e, item)"@mouseleave="preview.show = false"/></div><div class="module_view" v-show="preview.show" :style="previewStyle"><img :src="preview.url" class="img" /></div></div></div>
</template><script>
import { defineComponent, ref, reactive, computed } from 'vue'
import { getImg } from '@/utils/imgExample'export default defineComponent({setup() {const imgList = ref(getImg(0, 12))const listRef = ref(null)const preview = reactive({top: 0,bottom: 0,url: '',show: false})const previewStyle = computed(() => {// 弹窗实际高度const previewHeight = 538const container = listRef.value// 容器与视口顶部距离const containerTop = container ? container.getBoundingClientRect().top : 0const previewTop = preview.topconst previewBottom = preview.bottom// 弹窗顶部与容器顶部的距离let top = previewTop - containerToplet bottom = previewBottom - previewHeight// 判断弹窗顶部与视口底部的距离是否能容纳整个弹窗if (bottom < 0) {// 无法容纳时，减小弹窗顶部距离容器顶部的距离从而抬升弹窗// 还需判断抬升后弹窗顶部与视口顶部是否仍大于0，否则设置为置顶距离，即负的容器与视口顶部距离top = previewTop + bottom > 0 ? top + bottom : 0 - containerTop}return {top: top + 'px'}})// 获取当前图片顶部与视口顶部的距离top和底部的距离bottomconst handlePreview = (e, url) => {const targetRect = e.target.getBoundingClientRect()preview.bottom = window.innerHeight - targetRect.toppreview.top = targetRect.toppreview.url = urlpreview.show = true}return {listRef,imgList,preview,previewStyle,handlePreview}}
})
</script><style lang="less" scoped>
.image_view {width: 100%;height: 100%;.image_list {position: relative;width: 404px;height: 100%;padding: 12px;border: 1px solid #ededed;display: flex;flex-wrap: wrap;gap: 8px;.image_item {width: 120px;height: 120px;border-radius: 4px;overflow: hidden;.img {width: 100%;height: 100%;object-fit: cover;}}.module_view {position: absolute;top: 0;right: -404px;width: 400px;height: 528px;background: #fff;box-shadow: 0 4px 10px 2px rgba(0, 0, 0, 0.16);padding: 8px;border-radius: 12px;}}
}
</style>