Sometimes drawText works, other times not?

[dmb0058]

I have an application that writes text directly onto pages in a PDF file using pdf-lib. However sometimes the text doesn't appear in the result.

Now I just noticed that this is on PDF files with embedded fields, so I'm wondering if there's some sort of z-index problem where the text is written onto the 'background' and then the empty field is written into a layer above masking it (apologies if this makes no sense, I'm not a PDF structure expert :) ).

Can I use pdf-lib to strip out all the fancy field stuff so that I just start with a bunch of flat pages? Or flatten the empty fields in the original so that there are no fields in the file, only 'image boxes' where the fields were?

Any help much appreciated :)

[dmb0058]

Ths background to this is that I was trying to open a PDF file that had a version higher than 1.4, and was getting the error "This PDF document probably uses a compression technique which is not supported by the free parser shipped with FPDI."

In case it helps anyone, the answer is "Yes", pdf-lib can open and flatten documents like this:

'use strict';

const fs = require('fs');
const { PDFDocument } = require('pdf-lib');

async function copyPdfWithoutFields(inputPdfPath, outputPdfPath)
{
  const inputPdfBytes = fs.readFileSync(inputPdfPath);
  const inputPdf = await PDFDocument.load(inputPdfBytes);

  const newPdf = await PDFDocument.create();

  const pageCount = inputPdf.getPageCount();
  for (let i = 0; i < pageCount; i++) {
    const [embeddedPage] = await newPdf.embedPages([inputPdf.getPages()[i]]);
    const { width, height } = embeddedPage;

    const newPage = newPdf.addPage([width, height]);
    newPage.drawPage(embeddedPage);
  }

  const newPdfBytes = await newPdf.save();

  fs.writeFileSync(outputPdfPath, newPdfBytes);
}

Example usage:

(async () => {
  const inputPdfPath = './input.pdf';
  const outputPdfPath = './output.pdf';

  try {
    await copyPdfWithoutFields(inputPdfPath, outputPdfPath);
  } catch (error) {
    console.error('Error copying PDF:', error);
  }
})();