# [Dev-luatex] synctex and text direction

Hartmut Henkel hartmut_henkel at gmx.de
Thu Jun 11 18:16:14 CEST 2009

Hi Jerome,

On Thu, 11 Jun 2009, Jérome Laurens wrote:

> I am currently digging into luatex to fix synctex support when
> typesetting does not follow the standard ltr order. Hartmut suggested
> to take a look at the box direction so I tried to use the
> box_dir(aNode). With a bit of reverse engineering, I found how to use
> this information, but I need some confirmations from you. For the
> moment, I focus on hlists and I have a few questions.
>
> 1) I found that \pardir ignores the first letter argument, is it expected
> behaviour ?

(unsure here, and current complexity is beyond me, just too many \vice-
and \deputy- direction primitives, and maybe overall just \textdir +
\mathdir + the possibility to state the box dir like in \hbox dir *** {}
+ let it bubble down from the top box to be shipped + obey grouping +
ignore if it's \hbox or \vbox would be sufficient, but it's wishful
thinking only. Anyway it's aleph legacy, rather fixed.)

> 2) What is the difference between \texdir LTB and \textdir RTB ?

please see attached graphics, easier than describing...

> 3) for a box created with \texdir LTB , the height and the depth are
> equal. Is it always true ?

for height/depth contributed into the packer by text, yes. But if in the
line is a box or rule, i would rather like to have full control over
"vertical" positioning, in the way that then the 1st letter would tell
the vertical main orientation of the item. Which means that box
placement should completely ignore the 3rd letter, which should matter
for glyphs only. But that's currently not so. AFAIR boxes would also be
"vertically" centered. Maybe a point for discussion.

> 4) I saw that text direction has something to do with rulers, but what
> about the other nodes ?

(btw, rulers also shouldn't have to do with the 3rd letter, imho.)

> On another respect, I see that none of luatex nor context command
> supports the -synctex option. Is there a special reason or is it just
> a bug ?

synctex support is on by \synctex=1 in the tex file. There may be a
flaw, that last time i checked it seemed to be always _on_ by default.

Regards, Hartmut
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