[pdftex] Character protruding

[Gerolf]

At 12/15/2001, I asked:

> Can I deduce \rpcode for protruding from the character width or from 
> \fontdimen parameters?

Thierry Bouche wrote:

>Of course not, rpcode is something like kern pairs, it has to be
>visually twickled font per font.
>
I have feared something like this because TeX doesn't know what the 
glyphs look like...

>Don't focus on the right margin (and hyphens) exclusively, as
>some dumb DTP programs, if you want optical justification, you need
>to consider both margins, and chars like v or w should have a
>symetrical treatment, etc.
>
I see, you want to do it perfectly. My first impression was that it 
already helps a lot to simply shift hyphen, point, comma completely into 
the margin. Would you say that it isn't possible to give rules of thumb 
for some worst cases, so that I can use different fonts?

>Here I mention french because the thin space before double punctuation 
>makes that you can't treat it the same way (putting ot almost entirely 
>into the margin) as a point or a coma. 
>
Je ne comprends pas la deuxième partie de cette phrase. Pouvez-vous me 
donner un exemple?

Hans Hagen wrote:

> You can best look into the example file that comes with pdftex since 
> that reflects the latest methods. Keep in mind that protruding is part 
> of thanh's experiments and that in a coming cleanup of code things may 
> change (actually that did change from % of char width into % of em).

Thank you for these hints. I'm going to study "protcode.tex" and 
"il2protcode.tex".

Regards,

Gerolf