[pdftex] Character protrusion / manual / man page

[Thierry Bouche]

»     \font \myfont = X at  Ypt
»     \pdfprotrudechars = 2 % consider protrusion for line-breaking
»     \rpcode \myfont `\- = 700
» 
» Thanh is doing this for a serif font, I suppose. However, if I'm using 
» the Acrobat Reader built-in font "Helvetica", I must say
» 
»     \rpcode \myfont `\- = 300
» 
» to get even borders. So \rpcode is font-specific as well as 
» character-specific. 

thus the syntax \rpcode\font\char...

» Now for my question: Can I deduce \rpcode from the 
» character width, or is there a general rule to compute \rpcode from 
» \fontdimen parameters? -


Of course not, rpcode is something like kern pairs, it has to be
visually twickled font per font.

I have a set of rp/lpcode working well for an humane font in french,
and another one for italics. It works well to apply the same set to
all body sizes or weights of a given font, but italics and romans need 
different settings. 

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.

Btw, 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. The trick is to turn your pages by 180° to
see how ragged are the margins.

Cheers,

Thierry Bouche