pdf.js实现web h5预览pdf文件（兼容低版本浏览器）

注意

使用的是pdf.js 版本为 v2.16.105。因为新版本兼容性不太好，部分手机预览不了，所以采用v2版本。

解决部分浏览器或者手机系统的兼容问题

  //解决 structuredClone// https://developer.mozilla.org/en-US/docs/Web/API/structuredClone#browser_compatibility// https://gitcode.com/zloirock/core-js/overview?utm_source=csdn_github_acceleratorimport structuredClone from 'core-js-pure/actual/structured-clone';// 解决 TypeError: key.split(...).at is not a function// https://github.com/wojtekmaj/react-pdf/issues/1465import 'core-js/features/array/at';window.structuredClone = structuredClone;

代码

以下为在uniapp vue3 实现 h5 预览pdf文件的代码有使用vant（手指缩放功能只写了一点，是不能用的）。

<template><div id="pdf-view" ref="pdfView"><!--    <canvas v-for="page in state.pdfPages" :key="page" id="pdfCanvas" />--><div ref="pdfViewContainer"><divv-for="pageNumber in state.pdfPages"v-show="state.pdfPageList.includes(pageNumber)":key="pageNumber":ref="(el) => (pageRefs[pageNumber - 1] = el)"></div></div><je-loading v-show="loading" /></div>
</template>
<script setup>//解决 structuredClone// https://developer.mozilla.org/en-US/docs/Web/API/structuredClone#browser_compatibility// https://gitcode.com/zloirock/core-js/overview?utm_source=csdn_github_acceleratorimport structuredClone from 'core-js-pure/actual/structured-clone';// 解决 TypeError: key.split(...).at is not a function// https://github.com/wojtekmaj/react-pdf/issues/1465import 'core-js/features/array/at';import * as pdfjsWorker from 'pdfjs-dist/lib/pdf.worker.js';// 解决  pdfjsWorker 未定义window.pdfjsWorker = pdfjsWorker;window.structuredClone = structuredClone;// if (!Array.prototype.at) {//   Array.prototype.at = function (index) {//     if (index < 0) {//       index = this.length + index;//     }//     if (index >= 0 && index < this.length) {//       return this[index];//     }//     return undefined;//   };// }import Hammer from 'hammerjs';import * as pdfjsWorker from 'pdfjs-dist/lib/pdf.worker.js';// 解决  pdfjsWorker 未定义window.pdfjsWorker = pdfjsWorker;import 'pdfjs-dist/web/pdf_viewer.css';import * as PDF from 'pdfjs-dist';// import * as PDF from 'pdfjs-dist/build/pdf.js';import { useRoute } from 'vue-router';import { ref, reactive, onMounted, nextTick, defineProps } from 'vue';import { showFailToast } from 'vant';const route = useRoute();const props = defineProps({src: {type: String,default: '',},});const pdfViewContainer = ref(null);const pdfView = ref(null);const pageRefs = ref([]);const loading = ref(false);const state = reactive({// 总页数pdfPages: 1,pdfPageList: [], //有效页码列表// 页面缩放pdfScale: 1,});let pdfDoc = null;async function loadFile(url) {// {//   url,//     cMapUrl: 'https://cdn.jsdelivr.net/npm/pdfjs-dist@2.16.105/cmaps/',//   cMapPacked: true,// }loading.value = true;// 设置配置选项 手势缩放PDF?.DefaultViewerConfig?.set({handToolOnDblClick: true,mouseWheelScale: true,});let arrayBufferPDF;//// if (navigator.userAgent.indexOf('QQ')) {//   const pdfData = await fetch(url);//   arrayBufferPDF = await pdfData.arrayBuffer();// }// 解决部分机型浏览器 undefined is not an object(evaluating 'response.body.getReader')// https://www.qingcong.tech/technology/javascript/a-pdfjs-bug-in-qq.html#%E8%A7%A3%E5%86%B3%E5%8A%9E%E6%B3%95fetch(url).then(async (pdfData) => {console.log('pdfData', pdfData);if (!pdfData.ok) {loading.value = false;showFailToast({message: '预览地址不存在或已失效',duration: 0,});// window.JE.alert('预览地址不存在', 'error');return;}arrayBufferPDF = await pdfData.arrayBuffer();const loadingTask = arrayBufferPDF? PDF.getDocument({ data: arrayBufferPDF }): PDF.getDocument(url);loadingTask.promise.then((pdf) => {pdfDoc = pdf;// 获取pdf文件总页数state.pdfPages = pdf.numPages;nextTick(() => {for (let i = 0; i < state.pdfPages; i++) {renderPage(i + 1); // 从第一页开始渲染}});});});}function initPinchZoom() {const pdfViewEl = pdfView.value;const hammer = new Hammer(pdfViewEl);// 启用捏合缩放手势hammer.get('pinch').set({ enable: true });// 启用拖动手势,设置拖动方向为所有方向,阈值为0hammer.get('pan').set({ direction: Hammer.DIRECTION_ALL, threshold: 0 });let initialScale = 1; // 初始缩放比例let deltaX = 0; // 当前水平拖动距离let deltaY = 0; // 当前垂直拖动距离let startX = 0; // 拖动开始时的水平位置let startY = 0; // 拖动开始时的垂直位置const MIN_SCALE = 1; // 最小缩放比例const MAX_SCALE = 4; // 最大缩放比例let lastPinchTime = 0; // 上一次捏合事件的时间戳let lastPanTime = 0; // 上一次拖动事件的时间戳// 捏合开始事件处理函数hammer.on('pinchstart', (event) => {initialScale = state.pdfScale; // 记录初始缩放比例startX = deltaX; // 记录拖动开始时的水平位置startY = deltaY; // 记录拖动开始时的垂直位置});// 捏合移动事件处理函数hammer.on('pinchmove', (event) => {const currentTime = Date.now();// 节流控制,限制事件触发频率if (currentTime - lastPinchTime > 50) {event.preventDefault();const scale = event.scale; // 获取当前捏合的缩放比例const newScale = Math.min(Math.max(initialScale * scale, MIN_SCALE), MAX_SCALE); // 计算新的缩放比例,限制在最小和最大缩放比例之间state.pdfScale = newScale; // 更新缩放比例状态applyTransform(); // 应用变换lastPinchTime = currentTime; // 更新上一次捏合事件的时间戳}});// 捏合结束事件处理函数hammer.on('pinchend', (event) => {initialScale = state.pdfScale; // 更新初始缩放比例为当前缩放比例limitPanPosition(); // 限制拖动位置范围renderPages(); // 重新渲染页面});// 拖动开始事件处理函数hammer.on('panstart', (event) => {pdfViewEl.style.transition = 'none'; // 禁用拖动过渡效果startX = deltaX; // 记录拖动开始时的水平位置startY = deltaY; // 记录拖动开始时的垂直位置});// 拖动移动事件处理函数hammer.on('panmove', (event) => {const currentTime = Date.now();// 节流控制,限制事件触发频率if (currentTime - lastPanTime > 50) {const dx = event.deltaX; // 获取当前拖动的水平距离const dy = event.deltaY; // 获取当前拖动的垂直距离deltaX = startX + dx; // 计算新的水平拖动距离deltaY = startY + dy; // 计算新的垂直拖动距离applyTransform(); // 应用变换lastPanTime = currentTime; // 更新上一次拖动事件的时间戳}});// 拖动结束事件处理函数hammer.on('panend', (event) => {pdfViewEl.style.transition = 'transform 0.3s ease'; // 启用拖动过渡效果limitPanPosition(); // 限制拖动位置范围});// 限制拖动位置范围的函数function limitPanPosition() {const pdfWidth = pdfViewEl.clientWidth * state.pdfScale; // 计算PDF页面的实际宽度const containerWidth = pdfViewContainer.value.clientWidth; // 获取容器的宽度const containerHeight = pdfViewContainer.value.clientHeight; // 获取容器的高度// 计算单个页面的平均高度const averagePageHeight =pageRefs.value.reduce((totalHeight, pageRef) => {return totalHeight + (pageRef ? pageRef.clientHeight : 0);}, 0) / state.pdfPageList.length;// 估算总高度,使用PDF文档的总页数乘以单个页面的平均高度const estimatedTotalHeight = state.pdfPages * averagePageHeight * state.pdfScale;// 限制水平拖动距离,确保PDF页面在容器内部deltaX = Math.min(0, Math.max(deltaX, containerWidth - pdfWidth));// 限制垂直拖动距离,确保PDF页面在容器内部,使用估算的总高度deltaY = Math.min(0, Math.max(deltaY, containerHeight - estimatedTotalHeight));applyTransform(); // 应用变换}// 应用变换的函数function applyTransform() {pdfViewEl.style.transform = `translate(${deltaX}px, ${deltaY}px) scale(${state.pdfScale})`; // 设置PDF页面的变换样式}}function renderPages() {state.pdfPageList = [];for (let i = 0; i < state.pdfPages; i++) {renderPage(i + 1);}}function renderPage(num) {pdfDoc.getPage(num).then((page) => {// 获取当前页面对应的DOM容器元素const container = pageRefs.value[num - 1];// 创建一个新的canvas元素const canvas = document.createElement('canvas');// 获取canvas的2D渲染上下文const ctx = canvas.getContext('2d');// 获取设备像素比let devicePixelRatio = window.devicePixelRatio || 1;// 获取画布的backing store ratiolet backingStoreRatio =ctx.webkitBackingStorePixelRatio ||ctx.mozBackingStorePixelRatio ||ctx.msBackingStorePixelRatio ||ctx.oBackingStorePixelRatio ||ctx.backingStorePixelRatio ||1;// 获取pdfViewContainer元素的宽度const pdfWrapperElWidth =pdfViewContainer.value.clientWidth ||pdfViewContainer.value.offsetWidth ||pdfViewContainer.value.style.width;// 获取PDF页面的初始视口,缩放比例为1const intialisedViewport = page.getViewport({ scale: 1 });// 计算缩放比例,使PDF页面宽度与容器宽度一致const scale = pdfWrapperElWidth / intialisedViewport.width;// 计算设备像素比与backing store ratio的比值let ratio = devicePixelRatio / backingStoreRatio;// 根据缩放比例获取PDF页面的视口const viewport = page.getViewport({ scale });// 设置canvas的宽度为容器宽度乘以ratio,确保高分辨率下的清晰度canvas.width = pdfWrapperElWidth * ratio;// 设置canvas的高度为视口高度乘以ratio,确保高分辨率下的清晰度canvas.height = viewport.height * ratio;// 设置canvas的样式宽度为100%,与容器宽度一致canvas.style.width = '100%';// 设置canvas的样式高度为auto,根据宽度自适应canvas.style.height = 'auto';// 缩放画布的渲染上下文,根据ratio进行缩放,确保在高分辨率下绘制的清晰度ctx.scale(ratio, ratio);const renderContext = {canvasContext: ctx,viewport,};// 设置页面容器的高度为视口高度container.style.height = `${viewport.height}px`;page.render(renderContext).promise.then(() => {state.pdfPageList.push(num);// 如果 container 存在 canvas元素 覆盖canvas元素container?.firstChild && container.removeChild(container.firstChild);container && container.appendChild(canvas);}).finally(() => {if (num === state.pdfPages) {loading.value = false;}});});}onMounted(() => {const file = route.query.file && JSON.parse(decodeURIComponent(route.query.file));const { relName, previewUrl } = file || {};if (relName) {// 设置 uniapp 当前页面标题uni.setNavigationBarTitle({title: relName,});}if (previewUrl) {loadFile(previewUrl);// nextTick(() => {//   initPinchZoom();// });} else {showFailToast({message: '预览地址不存在',duration: 0,});}});
</script>
<style scoped lang="less">uni-page-body {overflow-y: scroll;}
</style>