Node.js 環境中的 fjsPDF 加載黑色方塊而不是 png 圖像

Question

我正在嘗試在 node.js 環境中生成一個 pdf 文件。 我正在運行節點 v 14.17.6。 我看到的問題是，當我嘗試從工作目錄加載 png 圖像時，pdf 中的圖像只是占用相同空間的黑色方塊。 我已經嘗試保存刪除了透明度的圖像，因為我已經看到了一些問題。

注意：這一切都是在 node.js 環境中完成的，而不是在瀏覽器中。 我花了一個多小時尋找重復項，但大多數重復項似乎都集中在瀏覽器環境中的 canvas 或 img 元素的操作上，而不是全部在服務器端。

下面的代碼是該問題的大規模縮小再現（您只需要一個帶有 jspdf @ 2.5.1 的 package.json 文件和同一目錄中的圖像，在本例中為 blue.png）

import fs from 'fs';
import { jsPDF } from 'jspdf';

const file = fs.readFileSync('blue.png');
const fileUri = `data:image/png;base64,${file.toString('base64')}`;

const pdf = new jsPDF('p', 'mm', [400, 500]);
pdf.addImage(fileUri, 'png', 100, 100, 200, 300);

fs.writeFileSync('test.pdf', pdf.output());

package.json 在這里：

{
  "name": "stack",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "type": "module",
  "dependencies": {
    "jspdf": "^2.5.1"
  }
}

更新：

import fs from 'fs';
import { jsPDF } from 'jspdf';
import Base64 from 'base-64';
import PNGJS from 'png-js';

const file = fs.readFileSync('blue.png');
console.log(file);
const fileUri = `data:image/png;base64,${file.toString('base64')}`;

global.btoa = Base64.encode; 
global.html2pdf = {};
global.window = {document: {createElementNS: () => {return {}} }};
global.navigator = {};
global.PNG = PNGJS;

const pdf = new jsPDF();
pdf.addImage(fileUri, 'PNG', 40, 20, 0, 0);
fs.writeFileSync('test.pdf', pdf.output());

delete global.btoa;
delete global.PNG;
delete global.window;
delete global.navigator;
delete global.html2pdf;

DataUri: data:image/png;base64,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 1xYW52rlKO58sEQjFu9+cj/seFf/2OKdHiNLFcLBWK8ViJuFAiTcd5uVKRRCHJleIS6X8y8R+W/QmTdw0ArIZPwE62B7XLbMB+7gECiw5Y0nYAQH7zLYwaC5EAEGc0Mnn3AACTv/mPQCsBAM2XpOMAALzoGFyolBdMxggAAESggSqwQQcMwRSswA6cwR28wBcCYQZEQAwkwDwQQgbkgBwKoRiWQRlUwDrYBLWwAxqgEZrhELTBMTgN5+ASXIHrc 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​​UCdLJ31Om0693UJuja6UbqFutt1z+o+02PreekJ9cr1Dund0Uf1bfSj9Rfq79bv0R83MDQINpAZbDE4Y/DMkGPoa5hpuNHwhOGoEctoupHEaKPRSaMnuCbuh2fjNXgXPmasbxxirDTeZdxrPGFiaTLbpMSkxeS+Kc2Ua5pmutG003TMzMgs3KzYrMnsjjnVnGueYb7ZvNv8jYWlRZzFSos2i8eW2pZ8y 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 GnsqcTz8p+Vv9563Or59/94vtLz1j82PAL+YvPv655qfNy76uprzrHI8cfvM55PfGm/K3O233vuO+638e9H5ko/ED+UPPR+mPHp9BP9z7nfP78L/eE8/stRzjPAAAAIGNIUk0AAHomAACAhAAA+gAAAIDoAAB1MAAA6mAAADqYAAAXcJy6UTwAAAAJcEhZcwAACxMAAAsTAQCanBgAAAMQSURBVHic7d1NTttgFEDRDydkkG2wBnbBClkII9bCIvgTP3booBITIGqlFt+q50xj63uDq2dFiuKTw+Ht4WHc3o77+/H0NF5exhjj7m78tCzj+Xm8e3wcn3p9HYfD5x99tCy/emXEZvMdp2y333TQ+3G73fcdN8bY73/7lmUZZ2dje3U1Li7+wkTwJ1xejmntGeCY3U6j5GmUuumrr0EQYY9Sp1HqNEqdRqnTKHUapU6j1GmUOo1Sp1HqNErd9M/94pj/zTTPa48AR3nWU6dR6jRKnUap0 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

更新：答案是 writeFileSync 函數。 我沒有指定此參數，而是使用了默認編碼 (utf-8)。 這不起作用。 在下面的答案中指定“二進制”或“ascii”使這項工作有效。

fs.writeFileSync('test.pdf', pdf.output(), 'ascii');

Answer 1

我已經參考了 jspdf 庫示例中提供的代碼，它對我來說工作得很好。 代碼輸出見下圖。

在此處添加代碼示例以提高可見性。

 ...imports var Octocat = fs.readFileSync("../images/Octocat.png", { encoding: "latin1" }); var doc = new jsPDF(); doc.setFontSize(40); doc.text("Octocat loves jsPDF", 40, 30, 4); doc.addImage(Octocat, "test", 10, 40, 180, 180, undefined, "SLOW"); fs.writeFileSync("./Octocat.pdf", doc.output(), "ascii");

如果我誤解了您的問題，請發表評論。

Answer 2

您不需要使用 writeFileSync。 只需使用 pdf.save() 即可。

import fs from 'fs';
import { jsPDF } from 'jspdf';

const file =  fs.readFileSync('./cat.png');

const fileUri =  `data:image/png;base64,${file.toString('base64')}`;
console.log(fileUri)
const pdf = new jsPDF();
pdf.addImage(fileUri, 'PNG', 15, 40, 180, 160);
pdf.save("cat.pdf")