[luatex] using (pdf)lualatex

[Arthur Reutenauer]

> Then why should we calculate the bounding box for each glyph? Well, as

  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."

>                                   But now different fonts/font
> types/TeX implementations have their own understanding of bounding
> boxes (also known as the font metrics)

  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.

>                             So I don't think bounding box for each
> glyph is needed in this situation, maybe we can use CFF's FontBBox as
> the largest value to test if the distance between two lines are good.

  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.

> Anyway, if you insist on the current implementation, go ahead, it's also great:)
> But I will test luapdflatex later until I buy a new computer if it
> does not provide a font cache feature......

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

	Arthur