Okular moving (covering parts of .pdfs)

[Kuba Ober]

> > It's a trivial matter to print the .pdf to a postscript
> > file, and remove the obliterations by hand.
>
> No, it's not. And if it is, may I send you a few example files and
> ask you to do that trivial job for me?

A typical scenario is someone receiving a document as a word file, adding 
obliterating rectangles, and exporting it to .pdf. It is known *not* to 
remove information. That's what non-technical users are known to do, and it 
has caused some more-or-less publicized information leaks. The geeks in the 
know had a field day, of course, but the truth is that IIRC current printing 
architectures do not do full clipping on output (including bitmap clipping).

If you do the obliteration correctly by doing full clipping, then you have a 
point. As things currently are, most .pdfs out there that *do* have 
obliterations have them in "overpaint" style, with nothing clipped.

Also note that the "obliteration" aspect needs to be handled across the board: 
someone running (cough, cough) MS Office under Wine and printing out via 
kprinter should see it working as well. I.e. if I get a word document, put a 
black rectangle somewhere, shell it out via kprinter to a .pdf, I should 
get .pdf output with no information leaks.

If that's your goal, then it's a worthy one. Otherwise, it's just giving 
non-techie types hard time.

Cheers, Kuba