Re: Patch to align baseline of latex fragments and surrounding text

[Sébastien Miquel]

Matt Huszagh writes:
> > I couldn't get ~org--match-text-baseline-ascent~ to compute the
> > ascent : the ~xml-get-attribute~ call returns
> >    : ("-16.945024" "12.153473" "16.148855" "8.064997")
> > which gives an ascent < -100, and the code then defaults to 'center.
> I'd need to know more about your setup for generating latex
> fragments. Did you follow all the directions in
> org--match-text-baseline-ascent? How is your org-format-latex-header
> set? In particular, are you using \documentclass[preview]{standalone}?
> If you can provide me with the TeX file used to generate the fragment,
> as well as the SVG file you get as a result, that would be helpful too.
My mistake. For some reason, I had thought that
=\documentclass[preview]{standalone}= was used by default for LaTeX
previews. Setting it as described in your patch, it now works
properly, even with the default value of =dvisvgm=.

> > If there are no drawbacks, perhaps this behaviour should be the
> > default. Otherwise, it should at least be easier to toggle.
> I didn't attempt to make this the default because it requires a specific
> setup, which is also different from the current default setup in other
> respects. Most importantly, it requires using the standalone document
> class, though I believe article is used at the moment.

To make this behavior easier to toggle, you could
 1. Change the default value of =org-format-latex-header=. The
    =standalone= class makes sense, but I don't know if that might
    break things.
 2. Specify the =:latex-header= of the default =dvisvgm= option. Same
    caveat applies.
 3. Add a =dvisvgm-with-ascent= option to the default value of
    =org-preview-latex-process-alist=.

Instead of the new variable =org-latex-fragment-overlay-ascent=,
perhaps the function used to compute the ascent could be provided as
another property, such as =:ascent=, added to the relevant options in
=org-preview-latex-process-alist=. It seems to make more sense since
it only applies to svg output, and it makes it easier to have this
behavior as default. It would require =org--make-preview-overlay= to
take the ascent as an additional argument.

Please note that I am not a maintainer, these are just a few thoughts.
I do hope your work can be applied and that LaTeX fragments can be
properly aligned by default.

You should add [PATCH] to the subject of your mail, so that it gets
listed at https://updates.orgmode.org/ and not forgotten. A maintainer
will reply eventually, but it might take up to a few months.

Regards,

--
Sébastien Miquel