vite：npm 安装 pdfjs-dist , PDF.js View 预览功能示例

发布于：2025-05-12 ⋅ 阅读:(16) ⋅ 点赞:(0)

pdfjs-dist 是 Mozilla 的 PDF.js 库的预构建版本，能让你在项目里展示 PDF 文件。下面为你介绍如何用 npm 安装 pdfjs-dist 并应用 pdf.js 和 pdf.worker.js。

为了方便，我将使用 vite 搭建一个原生 js 项目。

1.创建项目
npm create vite@latest pdf-view
选：Vanilla
选：JavaScript

2.初始化项目
 cd pdf-view
 cnpm install

3.安装 pdfjs-dist
 cnpm install pdfjs-dist@3.11.174 --save

编写 index1.html  如下

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>PDF.js View 示例</title>
  <link rel="stylesheet" href="/pdf.css" />
</head>
<body>
  <div class="container">
    <input type="file" id="fileInput" accept=".pdf">
    
    <div class="controls">
      <button id="prevPage">← 上一页</button>
      
      <div class="page-control">
        <input type="number" id="pageInput" min="1" step="1" disabled>
        <button id="goButton" disabled>跳转</button>
        <span>/ <span id="totalPages">-</span></span>
      </div>
      
      <button id="nextPage">下一页 →</button>
      
      <div class="scale-control">
        <button id="zoomOut">-</button>
        <span id="scaleValue">100%</span>
        <button id="zoomIn">+</button>
      </div>
    </div>

    <div id="canvasContainer">
      <canvas id="pdfCanvas"></canvas>
    </div>
  </div>

  <script type="module" src="/pdf-view.js"></script>
</body>
</html>

 编写 pdf.css  如下

    .container {
      max-width: 1000px;
      margin: 10px auto;
      padding: 15px;
    }

    .controls {
      display: flex;
      gap: 10px;
      align-items: center;
      margin-bottom: 15px;
    }

    #canvasContainer {
      border: 1px solid #ddd;
      overflow: auto;
      max-height: 80vh;
      position: relative;
    }

    canvas {
      transition: transform 0.2s ease;
    }

    input[type="number"] {
      width: 60px;
      padding: 4px;
      text-align: center;
    }

    button {
      padding: 6px 12px;
      background: #007bff;
      color: white;
      border: none;
      border-radius: 4px;
      cursor: pointer;
    }

    button:disabled {
      background: #6c757d;
      cursor: not-allowed;
    }

    .scale-control {
      margin-left: auto;
      display: flex;
      align-items: center;
      gap: 5px;
    }

编写 pdf-view.js  如下

import * as pdfjsLib from 'pdfjs-dist';
import pdfjsWorker from 'pdfjs-dist/build/pdf.worker.min.js';

// 初始化配置
pdfjsLib.GlobalWorkerOptions.workerSrc = pdfjsWorker;

// 状态管理对象
const state = {
  currentPage: 1,
  totalPages: 0,
  scale: 1.0,
  pdfDoc: null,
  isRendering: false,
  MIN_SCALE: 0.5,
  MAX_SCALE: 3.0,
  ZOOM_STEP: 0.1
};

// DOM 元素引用
const dom = {
  canvas: document.getElementById('pdfCanvas'),
  container: document.getElementById('canvasContainer'),
  prevBtn: document.getElementById('prevPage'),
  nextBtn: document.getElementById('nextPage'),
  pageInput: document.getElementById('pageInput'),
  goBtn: document.getElementById('goButton'),
  totalPages: document.getElementById('totalPages'),
  zoomIn: document.getElementById('zoomIn'),
  zoomOut: document.getElementById('zoomOut'),
  scaleValue: document.getElementById('scaleValue'),
  fileInput: document.getElementById('fileInput')
};

// 初始化事件监听
function initEventListeners() {
  // 文件选择
  dom.fileInput.addEventListener('change', handleFileSelect);

  // 翻页控制
  dom.prevBtn.addEventListener('click', () => changePage(-1));
  dom.nextBtn.addEventListener('click', () => changePage(1));

  // 页面跳转
  dom.goBtn.addEventListener('click', handlePageJump);
  dom.pageInput.addEventListener('keypress', e => {
    if (e.key === 'Enter') handlePageJump();
  });

  // 缩放控制
  dom.zoomIn.addEventListener('click', () => changeScale(state.ZOOM_STEP));
  dom.zoomOut.addEventListener('click', () => changeScale(-state.ZOOM_STEP));

  // 鼠标滚轮缩放
  dom.container.addEventListener('wheel', handleWheelZoom, { passive: false });
}

// 处理文件选择
async function handleFileSelect(e) {
  const file = e.target.files[0];
  if (!file) return;

  try {
    const arrayBuffer = await file.arrayBuffer();
    state.pdfDoc = await pdfjsLib.getDocument(arrayBuffer).promise;
    state.totalPages = state.pdfDoc.numPages;
    
    initUI();
    await renderPage();
  } catch (err) {
    console.error('文件加载失败:', err);
  }
}

// 初始化界面状态
function initUI() {
  dom.totalPages.textContent = state.totalPages;
  dom.pageInput.max = state.totalPages;
  dom.pageInput.value = 1;
  dom.pageInput.disabled = false;
  dom.goBtn.disabled = false;
  dom.zoomIn.disabled = false;
  dom.zoomOut.disabled = false;
}

// 核心渲染函数
async function renderPage() {
  if (!state.pdfDoc || state.isRendering) return;
  state.isRendering = true;

  try {
    const page = await state.pdfDoc.getPage(state.currentPage);
    const viewport = page.getViewport({ scale: state.scale });

    // 调整画布尺寸
    dom.canvas.width = viewport.width;
    dom.canvas.height = viewport.height;

    // 渲染页面
    await page.render({
      canvasContext: dom.canvas.getContext('2d'),
      viewport: viewport
    }).promise;

    updateUIState();
  } catch (err) {
    console.error('页面渲染失败:', err);
  } finally {
    state.isRendering = false;
  }
}

// 更新界面状态
function updateUIState() {
  dom.pageInput.value = state.currentPage;
  dom.totalPages.textContent = state.totalPages;
  dom.scaleValue.textContent = `${Math.round(state.scale * 100)}%`;
  
  // 按钮状态
  dom.prevBtn.disabled = state.currentPage <= 1;
  dom.nextBtn.disabled = state.currentPage >= state.totalPages;
  dom.zoomIn.disabled = state.scale >= state.MAX_SCALE;
  dom.zoomOut.disabled = state.scale <= state.MIN_SCALE;
}

// 翻页处理
function changePage(offset) {
  const newPage = state.currentPage + offset;
  if (newPage < 1 || newPage > state.totalPages) return;
  
  state.currentPage = newPage;
  renderPage();
}

// 页面跳转处理
function handlePageJump() {
  const target = parseInt(dom.pageInput.value) || 1;
  const validPage = Math.max(1, Math.min(target, state.totalPages));
  
  if (validPage !== state.currentPage) {
    state.currentPage = validPage;
    renderPage();
  }
}

// 缩放处理
function changeScale(delta) {
  state.scale = parseFloat(
    Math.max(state.MIN_SCALE, 
           Math.min(state.scale + delta, state.MAX_SCALE))
           .toFixed(1)
  );
  renderPage();
}

// 鼠标滚轮缩放处理
function handleWheelZoom(e) {
  if (!e.ctrlKey) return;
  e.preventDefault();
  
  const delta = e.deltaY > 0 ? -state.ZOOM_STEP : state.ZOOM_STEP;
  changeScale(delta);
}

// 启动应用
initEventListeners();

代码解释

  1. 导入 pdfjsLib 和 pdfjsWorker：借助 ES6 模块语法导入 pdfjs-dist 库和 pdf.worker.js。
  2. 设置 worker 源：把 pdfjsLib.GlobalWorkerOptions.workerSrc 设为 pdfjsWorker，从而让 PDF.js 能够正确使用 Web Worker。
  3. 加载 PDF 文件：利用 pdfjsLib.getDocument 方法加载指定的 PDF 文件。
  4. 渲染第一页：获取 PDF 的第一页，创建一个 canvas 元素，然后把页面渲染到 canvas 上。
  5. 错误处理：使用 .catch 方法捕获并处理加载 PDF 文件时可能出现的错误。

运行 npm run dev
  VITE v6.3.5  ready in 1066 ms

访问  http://localhost:5173/index1.html

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