Re: editing a PDF [Re: emacs 30.5.0 editing epub]

[Yuri Khan]

On Wed, 22 Mar 2023 at 22:46, Emanuel Berg <incal@dataswamp.org> wrote:

> > You don’t normally edit executable programs, you compile
> > them from source. In the same vein, to get a modified PDF,
> > you find the source document from which it was produced,
> > modify that, and re-export.
>
> Still, they are editable at/from the PDF level as well, for
> example with xournal.

That’s not really editing. You can scrawl over the existing text, you
can carefully overpaint existing text with your own, but you cannot
replace one word with a different word and hope the rest of the text
is repositioned to accommodate the change.

(To stretch the executable program analogy, you can append new
instructions to an existing program. They will be executed and may, in
limited cases, have your desired effect.)

Xournal doesn’t even claim it supports editing — the menu item is
called Annotate PDF.

Commercial, proprietary Acrobat (not the Reader variety, the full
suite) can, in limited ways, modify individual runs of text. But if
you overflow a line, it won’t do anything to help you, you just get an
overfull line.

> This is used for signing documents,
> for example.

I’d be very wary of putting my handwritten signature as an annotation
in a PDF document and giving that to another person. For all I know,
it would enable them to extract the annotation containing my signature
and apply it to a different document.