[luatex] using (pdf)lualatex

[Yue Wang]

>  It's weird that you're the one asking the question: Taco was exactly
> trying to find ways to avoid calculating the bounding bax of each
> individual glyph if possible, and you sort of told him "That's not
> acceptable, please calculate all of them, emulating that feature from
> FreeType."


No, I am not. I just want to say:
- Well, if we want to calculate it, then control box might be much
more efficient.
- If we dont calculate, good, we can use  1) TrueType/ OpenType's glyf
table 2) CFF's global bounding box, they are much better than giving 4
zeros.


>  Font metrics are related, but *not identical* to glyphs bounding
> boxes.  In particular, a glyph's advance width is very much different
> from the horizontal dimensions of its bouding box.  Try any italic font,
> for example.

Yes. But as far as I know, the only need in current luatex/mkiv is to
get the height and depth, and later use it to calculate the line skip.
when make box into lines (I mean in horizontal mode), we only need
width (not xmax-xmin) and origin point.

>  I also think that in very specific situations you can use the font's
> global bounding box, although you probably have to be very careful what
> you do.  But really, you seemed to be saying the exact contrary just
> before.

I mean in practice the global bounding box can be used to calculate
the line skip, although not good as bounding box, but very strict and
efficient.


>
>  LuaTeX will never implement such a cache mechanism, I hope that's
> clear.  Thus, the responsibility lies with the macro package.
>

I mean pdflualatex, not LuaTeX engine. Hans said in the ntg-mailing
list that he will implement a plain TeX package to use opentype fonts,
without font cache.

>        Arthur
>