[luatex] Subscript drop too large

[Hans Hagen]

On 9/27/2018 12:37 PM, Henri Menke wrote:
> On 9/27/18 7:50 PM, Hans Hagen wrote:
>> On 9/27/2018 7:23 AM, Henri Menke wrote:
>>> Dear list,
>>>
>>> When using a Unicode math font, the subscript drop increases by a lot.
>>> It does not seem to be font dependent, so it's likely an engine issue.
>>> Is there any parameter which I could tweak?
>>
>> all kind of math parameters .. like
>>
>> $ \the\Umathsubshiftdrop\textstyle\quad {gt}_{gt} $
>> $ \Umathsubshiftdrop\textstyle.2ex      {gt}_{gt} $
> 
> This partly answers the question, but it seems that there is something
> wrong with subscripts after boxes, see MWE below.  With XeTeX it looks
> okay and the drop is basically the same with and without a Unicode math
> font, but with LuaTeX the drop after the box is much larger with a
> Unicode math font whereas the drop after a regular atom is the same.
> 
> \ifdefined\directlua
>    \input luaotfload.sty
> \fi
> \font\math="Latin Modern Math" at 10pt
> $\hbox{gt}_{gt} gt_{gt}$
> \textfont0=\math
> $\hbox{gt}_{gt} gt_{gt}$
> \bye
thee drop shifts kick in after non-characters so if you don't want that 
you can just set them to zero (instead of the value set by the font)

(afaiks it looks the same as in pdftex)

Hans


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