k-yle / pdf-to-img

📃📸 Converts PDFs to images in nodejs

pdf-to-img

📃📸 Converts PDFs to images in nodejs.

Useful for unit tests of PDFs

Supports nodejs v18+, and comes with a CLI.

Install

npm install -S pdf-to-img

Important

You should use v4 by default. v4 requires nodejs v18 or later, and ESM modules.

If you can't upgrade to v4 yet, you can still use v3. If you use v3, you can safely ignore npm audit's warning about pdfjs-dist, since this library disables eval by default.

Example

NodeJS (using ESM Modules):

import { promises as fs } from "node:fs";
import { pdf } from "pdf-to-img";

async function main() {
  let counter = 1;
  const document = await pdf("example.pdf", { scale: 3 });
  for await (const image of document) {
    await fs.writeFile(`page${counter}.png`, image);
    counter++;
  }
}
main();

If your app does not support ESM modules, you can use v3 (see the warning above), or just change the import:

+ const { promises: fs } = require("node:fs");
- import { promises as fs } from "node:fs";
- import { pdf } from "pdf-to-img";

  async function main() {
+   const { pdf } = await import("pdf-to-img");
    let counter = 1;
    const document = await pdf("example.pdf", { scale: 3 });
    for await (const image of document) {
      await fs.writeFile(`page${counter}.png`, image);
      counter++;
    }
  }
  main();

Using jest (or vitest) with jest-image-snapshot:

import { pdf } from "pdf-to-img";

it("generates a PDF", async () => {
  for await (const page of await pdf("example.pdf")) {
    expect(page).toMatchImageSnapshot();
  }
});

// or if you want access to more details:

it("generates a PDF with 2 pages", async () => {
  const doc = await pdf("example.pdf");

  expect(doc.length).toBe(2);
  expect(doc.metadata).toEqual({ ... });

  for await (const page of doc) {
    expect(page).toMatchImageSnapshot();
  }
});

The pdf function accepts either a path to the file on disk, or a data URL (e.g. data:application/pdf;base64,...)

Options

You can supply a second argument which is an object of options:

const doc = await pdf("example.pdf", {
  password: "...", // if the PDF is encrypted

  scale: 2.0, // use this for PDFs with high resolution images if the generated image is low quality
});

CLI

npm i -g pdf-to-img@latest

# example:
pdf2img inputFile.pdf

# options:
# -s / --scale: set the scale (defaults to 3)
# -p / --password: the password to unlock the PDF
# -o / --output: the output folder, relative to the current working directory.