On pdf.flatten() check mark getting removed from flattened pdf

[satyajitnayk]

What were you trying to do?

When I try to flatten a pdf with checked check box, the flattened pdf is missing check mark in check boxes.

Visuals

original pdf	flattened pdf

How did you attempt to do it?

Tried with simple script using the file form_to_flatten.pdf

import fs from 'fs';
import { PDFDocument } from 'pdf-lib';

const flattenPDF = async () => {
  const pdfDocument = await PDFDocument.load(
    fs.readFileSync('form_to_flatten.pdf')
  );
  const pdfForm = pdfDocument.getForm();

  pdfForm.flatten();
  const pdfBytes = await pdfDocument.save();

  fs.writeFileSync('flattened.pdf', pdfBytes);
};

flattenPDF();

What actually happened?

the flattened pdf is missing check mark in check boxes.

What did you expect to happen?

the flattened pdf should not have missing check mark in check boxes.
They should be intact.

How can we reproduce the issue?

we can reproduce this using pdf & script provided in How did you attempt to do it? section.

Version

1.17.1

What environment are you running pdf-lib in?

Node

Checklist

• My report includes a Short, Self Contained, Correct (Compilable) Example.
• I have attached all PDFs, images, and other files needed to run my SSCCE.

Additional Notes

No response

Thoughts @Sharcoux @MatheusrdSantos !!

[satyajitnayk]

This could be possibly happening

1. mac preview & other pdf editing apps converts pdf version 1.7 to 1.3/other lower versions to make it backward compatible when we edit an PDF Apple Discussion Link
2. Apps modify the metadata of pdf's which resulting in this behavior. (Refer to screenshot)

[Sharcoux]

@satyajitnayk We don't use this feature, so I'm not sure that we will take the time to work on this. If someone could have a look and make a PR, that would be great.

[Sharcoux]

Solved in #56 and released in v2.1.6

[satyajitnayk]

@Sharcoux #56 does not fix the issue. Check marks & radio buttons still getting removed.

[RippleRurigaki]

@satyajitnayk

My confirmation is that the check and radio buttons do show up.

mac preview & other pdf editing apps converts pdf version 1.7 to 1.3/other lower versions to make it backward compatible when we edit an PDF Apple Discussion Link

Are you on Version 1.3 as you commen?

I don't know what is causing this,
If you can provide us with the version 1.3 file,
I will try to find out.

[Sharcoux]

Without new information, I will close this Issue in a week.