LuaTeX-ja

Fork

Hello,

With TeXLive 2019 the following LaTeX code

 \documentclass{article}
 \usepackage{amsmath}
 % \usepackage{mathptmx}
 % \usepackage{mathabx}
 \usepackage{luatexja}                   
 \begin{document}
 $\widetilde{\psi}$ $\widehat{\psi}$ % $\widebar{\psi}$
 $\tilde{\psi}$ $\hat{\psi}$ $\bar{\psi}$
 
 $\widetilde{a}$ $\widehat{a}$ % $\widebar{a}$
 $\tilde{a}$ $\hat{a}$ $\bar{a}$
 \end{document}

outputs \widetilde and \widehat symbols positioned to high
(see how it looks https://drive.google.com/file/d/1f3HrONkaPAkld_yEl8cRRiBUt3gy2uQZ/view?usp=sharing).
If I load mathabx style for \widebar command sequence, all \wide... symbols go to low with the greek letter.
In my real document I have used mathptmx + luatexja-fontspec, when I saw the problem.

I use luatex.exe v1.10.0 and luaotfload 2019/08/11 v2.991.
I also have TeXLive 2018 with luaotfload 2017/01/29 v2.8 at my disposal.
The problem in this older system is not present.
I have searched for the cause of the problem, if You are interested please read below what I have found.

The reported behaviour is caused by a new set_xheight function (from luaotfload/luaotfload-auxiliary.lua)
which is assigned to patch_font callback (from luaotfload/luaotfload-loaders.lua).
There is the following comment in luaotfload/luaotfload-loaders.lua:

     if type (fontdata) == "table" and fontdata.encodingbytes == 2 then
       --- We need to test for `encodingbytes` to avoid passing
       --- tfm fonts to `patch_font`. These fonts are fragile
       --- because they use traditional TeX font handling.
       luatexbase.call_callback ("luaotfload.patch_font", fontdata, specification, id)
     else
       luatexbase.call_callback ("luaotfload.patch_font_unsafe", fontdata, specification, id)
     end

If I replace the following conditional in "font_callback" function (from luatexja/ltj-rmlgbm.lua):

     if type (tfmdata) == "table" and tfmdata.shared then
           luatexbase.call_callback("luaotfload.patch_font", tfmdata, name)
     end

with the code from above, the mentioned symbols will be positioned at the right height again.
This is because patch_font_unsafe callback is used instead of patch_font,
which has assigned different set functions to it and set_xheight is not one of them.
I do not know if this change would damage the intended luatexja behaviour though.

I have found out that from the amsmath package only the following code is necessary in order to produce the incorrect output:

 \@ifundefined{cmex@opt}{\def\cmex@opt{7}}{}
 \ifnum\cmex@opt=7 \relax
   \DeclareFontShape{OMX}{cmex}{m}{n}{%
     <-8>cmex7<8>cmex8<9>cmex9%
     <10><10.95><12><14.4><17.28><20.74><24.88>cmex10%
   }{}%
   \expandafter\let\csname OMX/cmex/m/n/10\endcsname\relax
 % \else ...  
 \fi

I hope this information will be of some help.
And I would very much appreciate a fix of this problem.

Thanks in advance,
Lolita Tolenė