Okular moving (covering parts of .pdfs)

[Kuba Ober]

> > In order to remove content, you have to remove it, as in physically
> > overwriting the bits of image bitmaps in the .pdf, and clipping,
> > splitting and then removing the "hidden" paths. There's no other way.
> > There could be probably some postscript magic done to implement that, if
> > noone did so yet.
>
> I think the objective was to do such preparations prior to printing a
> document, so that the physical-paper-and-ink output would not have the
> undesired content. Otherwise, you are of course correct.

It's basic usability: people don't expect (why would they?!) that paper will 
be somehow different from the .pdf that their friend had asked for. So 
the .pdf send they will, and you have a nice information leak. Many people 
who print/present something will eventually end up making a .pdf and send it 
out.

It's such a basic usage scenario. Say I've been to a seminar and I want the 
presenter (who has been using obliterated classified reports as source 
material) to send me the presentation. I ask him to send a .pdf as I dislike 
closed formats. I usually end up getting a file with all the classified stuff 
in there, even though it looks and prints "fine". I've given a few speakers 
goosebumps that way. They were pretty mad that the .pdf export didnt filter 
those out (no, they didn't use free software).

Cheers, Kuba