On 2/18/2017 3:13 PM, David Carlisle wrote:
there is a full (plain TeX) example and screenshots in a (non)answer
on stackexchange
http://tex.stackexchange.com/a/354485
but in brief:
\left| T \right|
has a kern between the T and the right hand | matching the kern in |T|
if tfm fonts are used in luatex or xetex or pdftex
but if Opentype Latin modern is used
xetex shows the kern but luatex has no kern once \right or \Uright are
used, but does still show the kern with |T|.
I'm not sure if this is a luatex or luaotfload issue?
It's a font issue ... try pagella or so ... latin modern has old math
font like properties so it has char boundingboxes / widths that assume
that italic correction is added.
For opentype fonts luatex doesn't use the traditional 8 bit font code
path. Early versions had a kind of hybrid but that failed miserably when
more opentype mathfonts came around and messy heuristics were dropped in
favour of separate code paths (not even lua magic could beat that so i
dropped most of that kind of hackery from context). Kerns have similar
issues as opentype has staircase kerns.
I can of course add a pseudo feature to the font loader that adds italic
to the width for fonts that need that. I might also cook up some magic
related to fences but again it's a macro package issue then.
The best solution is proper fonts.
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
