# pdf-to-img

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📃📸 Converts PDFs to images in nodejs.

Useful for unit tests of PDFs

Supports nodejs v20+, and comes with a CLI.

## Install

```sh
npm install -S pdf-to-img
```

## Example

NodeJS (using ESM Modules):

```js
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++;
  }

  // you can also read a specific page number:
  const page12buffer = await document.getPage(12);
}
main();
```

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

```diff
+ 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](https://npm.im/jest-image-snapshot):

```js
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:

```js
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
});
```

### Resource management

Document instances are not automatically freed from memory.
Once you have finished with `doc`, you should call `doc.destroy()`.

Or even better, replace `const` with `await using`.
This is a new JS language feature known as [explicit resource management](https://developer.mozilla.org/docs/Web/JavaScript/Guide/Resource_management), which is available in Node 24 and newer.

```diff
-  const       doc = await pdf("example.pdf");
+  await using doc = await pdf("example.pdf");
   for await (const page of doc) {
```

If you use `await using`, then you do not need to explicitly call `.destroy()`.
Instead, the document will automatically be destroyed at the end of [the block scope](https://developer.mozilla.org/docs/Glossary/Scope).

## CLI

```sh
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.
# -g / --pages: set which pages to convert. eg: 1,4,7 (defaults to all pages)
```