使用PDF.js生成pdf的缩略图 [英] Generating thumbnail of a pdf using PDF.js

问题描述

我想使用PDF.js从pdf文件生成缩略图，但它不像只有一个文件的其他js，并且所有需要在项目中包含js的是：

I would like to generate a thumbnail from a pdf file using PDF.js, but it isn't like anothers js that have just one file and all needed to include the js in your project is to write:

<script src="any.js"></script>

如何在项目中使用PDF.js？我在后端使用PHP。

How can I use PDF.js in my project? I'm using PHP in backend.

推荐答案

基于 helloworld示例：

function makeThumb(page) {
  // draw page to fit into 96x96 canvas
  var vp = page.getViewport(1);
  var canvas = document.createElement("canvas");
  canvas.width = canvas.height = 96;
  var scale = Math.min(canvas.width / vp.width, canvas.height / vp.height);
  return page.render({canvasContext: canvas.getContext("2d"), viewport: page.getViewport(scale)}).promise.then(function () {
    return canvas;
  });
}

PDFJS.getDocument("//cdn.mozilla.net/pdfjs/tracemonkey.pdf").promise.then(function (doc) {
  var pages = []; while (pages.length < doc.numPages) pages.push(pages.length + 1);
  return Promise.all(pages.map(function (num) {
    // create a div for each page and build a small canvas for it
    var div = document.createElement("div");
    document.body.appendChild(div);
    return doc.getPage(num).then(makeThumb)
      .then(function (canvas) {
        div.appendChild(canvas);
    });
  }));
}).catch(console.error);

<script src="//npmcdn.com/pdfjs-dist/build/pdf.js"></script>

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