[luatex] Bad skips with display math

[Hans Hagen]

On 1/13/2022 5:46 PM, Javier Bezos wrote:
> 
>> 👍 It didn’t occur to me to think of the old good bidi features
>> of etex and I was just playing with \...dir’s. After some simple
>> tests it seems to do the trick.
> 
> After some additional tests, setting \predisplaydirection=0
> doesn’t seem the solution 🙁.
> 
> Any additional suggestions on how to make luatex usable for
> serious math typesetting with RTL languages will be welcome.
> This includes the possibility of manipulations at the lua
> level (for example, I’m wondering if something similar to the
> macro \lastlinelength in sec. 7.7.2 can be used to catch and
> fix the spacing).
> 
> I'm just looking for a solution. After tree weeks of fighting
> I’m somewhat desperate.
you can use callbacks to loop back overlists and see if some above glue 
was added and then go back till you find a line that you can then 
'repack' for testing to get the natural width

anyway, i have a patch for the r2l last line issue but as i'm in the 
middle of something else it has to wait for a few days to get included 
(maybe the weekend as i have to enter luatex mode)

Hans

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