On 06.07.17 23:46, Hans Hagen wrote:
Indeed the expansion is not reported. The kern value is unchanged but
there is an additional kern (factor) traveling with the kern node which
will be dealt with in the backend.
If you see no difference in the pdf file, then there is an issue inm the
macros or font related code.
Anyway, I can only speak for context, so what I observe is not what you
observe (others have to check that).
Here's another plain tex example:
\pdfvariable compresslevel0
\hsize=1sp
\input luaotfload.sty
\font\x="Latin Modern Roman:+kern" at 10pt \x
\expandglyphsinfont\font 1000 1000 5
\adjustspacing=2 vabe\par
\adjustspacing=3 vabe\par
\bye
In the uncompressed pdf, both lines are exactly the same. However, if I
remove lines 3 and 4 from the example, then there is indeed a
difference, so the problem seems to be with luaotfload (which I thought
uses context code)?
Level 1 is rather useless .. (it was part of experiments when pdftex
evolved) and by not mentioning it we hope that it will not be used
Level 1 makes sense for users who need to reproduce a document with
unchanged line (and page) breaks. But anyway, I'll keep in mind that the
luatex manual can't be trusted.
With luatex, however, there is no difference between
| \expandglyphsinfont 20 20 5 autoexpand
and
| \expandglyphsinfont 20 20 5
Because we don't have pre-generated (copies of) fonts at all,
OK, so I take it that autoexpand is always true. But then I wonder why
\expandglyphsinfont still accepts the autoexpand keywords at all, and
also the font table still has the key "auto_expand", if its value makes
no difference?
Existing expanded font instances are ignored, and only the base font
is embedded in the pdf. Expansion seems to be calculated mechanically
and linearly instead of taking into account the width axis of a
Multiple Master font.
There is no support for multiple masters which is obsolete technology
and (recently) has been cq. is being replaced by variable fonts.
Obsolete or not, MM fonts (and MetaFont) with their parametrised width
axis still allow typographically superior quality over expansion by
linear distortion. Variable fonts may well be the future, and I would be
excited to see them supported by luatex one day (I reckon this is not
yet the case?), but at present production-ready fonts don't even seem to
be available.
Best,
--
Robert
