[luatex] font expansion

[Robert]

Hi,

I'm resending this post from last year (19 April), as I never got an 
answer, and the questions still pertain to luatex 1.0.4:

Firstly, the manual says:

| When \adjustspacing has value 2, hz optimization will be applied to
| glyphs and kerns. When the value is 3, only glyphs will be treated.
| A value smaller than 2 disables this feature.

However, what I see is:
  * a difference between \adjustspacing=0 and \adjustspacing=1,
  * a difference between \adjustspacing=1 and \adjustspacing=2,
  * no difference between \adjustspacing=2 and \adjustspacing=3
(regardless of whether the font is expanded with \expandglyphsinfont or 
via the luaotfload interface).

So it seems that the former "compatibility" level 1 (same line breaks as 
without expansion), which according to the manual should no longer 
exist, still does; while the new level 3 does not (all the kerns are the 
same as for level 2). Could somebody explain this?

Here's a test file:
----------
\hsize=6cm
\tracingoutput1
\showboxbreadth\maxdimen
\showboxdepth\maxdimen
\input luaotfload.sty
\font\x="Latin Modern Roman" at 10pt \x
%\font\x="Latin Modern Roman:expansion=default" at 10pt \x
\expandglyphsinfont\x 20 20 5 autoexpand
\def\z#1{\adjustspacing=#1 When adjustspacing has value 2,
   hz optimization will be applied to glyphs and kerns.
   When the value is 3, only glyphs will be treated.
   A value smaller than 2 disables this feature.\par}
\z0\z1\z2\z3
\bye
----------

Secondly, I wonder about the status of the "autoexpand" qualifier to 
\expandglyphsinfont. AFAICT it is silently ignored, and fonts are always 
autoexpanded. Is this correct? Or would it still be possible to use 
pre-expanded font instances (say, from a MM font)?


Best,
-- 
  Robert

-- 
  Robert