组件分享之前端组件——基于pdf.js在线预览PDF文件

<script src="//mozilla.github.io/pdf.js/build/pdf.js"></script>

<h1>PDF.js 'Hello, world!' example</h1>

<canvas id="the-canvas"></canvas>

#the-canvas {
  border: 1px solid black;
  direction: ltr;
}

// 如果提供了来自远程服务器的绝对URL，则在该服务器上配置CORS头。
var url = 'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/examples/learning/helloworld.pdf';

// 通过<script>标签加载，创建访问PDF.js导出的快捷方式。
var pdfjsLib = window['pdfjs-dist/build/pdf'];

// 指定workerSrc属性。
pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';

// 异步下载PDF
var loadingTask = pdfjsLib.getDocument(url);
loadingTask.promise.then(function(pdf) {
  console.log('PDF loaded');
  
  // 获取第一页
  var pageNumber = 1;
  pdf.getPage(pageNumber).then(function(page) {
    console.log('Page loaded');
    
    var scale = 1.5;
    var viewport = page.getViewport({scale: scale});

    // 准备画布使用PDF页面尺寸
    var canvas = document.getElementById('the-canvas');
    var context = canvas.getContext('2d');
    canvas.height = viewport.height;
    canvas.width = viewport.width;

    // 渲染PDF页到画布上下文
    var renderContext = {
      canvasContext: context,
      viewport: viewport
    };
    var renderTask = page.render(renderContext);
    renderTask.promise.then(function () {
      console.log('Page rendered');
    });
  });
}, function (reason) {
  // PDF loading error
  console.error(reason);
});