Comment by jbarrow

1 year ago

Editing text in PDFs is _really_ hard compared to other document formats because most PDFs don't really encode the "physics" of the document. I.e. there isn't a notion of a "text block with word wrapping," it's more "glyphs inserted at location X with font Y."

If the PDF hasn't been made accessible, you have to do a lot of inferencing based on the layout about how things are grouped and how they should flow if you want to be able to make meaningful edits. Not impossible (Acrobat does it), but very challenging.

It's part of the legacy of PDF as a format for presentation and print jobs, rather than typesetting.

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jbarrow

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otsukare  1 year ago

Yes, and alongside formatting challenges, PDFs commonly only include the glyphs from the font that are actually used in the document.

So if you had PDF with "Hello World" on it, you could feasibly change it to "Hello Hello", but wouldn't be able to change it to "Goodbye World" (as the glyphs for "G", "b", "y", and "e" are not included in the PDF)

Sure, you could do a bit of detective work to figure out which font it was from the glyphs or something and lookup and insert new glyphs into the PDF, but I can't imagine a generic PDF editor being capable of doing this for you.

Some editors get around this but just straight up switching the font(s) for the whole PDF, so they'll look different after saving.

benatkin  1 year ago

It's still what a PDF editor, as it says in the title, would do. With a quick Google I found one that I hadn't heard about before, and it let me edit some text and save it for free.

  • TechDebtDevin  1 year ago

    Ask yourself, why would someone spend money on bandwidth for me to download something for free...

    • philjohnson  1 year ago

      PDF editor is used as a broadly encompassing term. Yes, other tools can edit existing text, but they upload your PDF to their servers, so it's not private if that's something you care about.

      There isn't anything off the shelf that enables editing existing text in the browser, but it's something I'll build from scratch. So you'll be able to edit existing PDF text without compromising privacy.

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