Re: [Pre-PATCH] Overhaul of the LaTeX preview system

[Karthik Chikmagalur]

> It worked well all around except for three things:
>
>     1. I had to set org-latex-preview-precompile to nil to produce the
>        preview for ~2000 snippets.  I got errors in process filters such
>        as arg-out-of-range, and Emacs completely blocked itself.  I can
>        confirm that mylatexformat is installed

1. Are you using xelatex/lualatex?  
2. If yes, precompilation should have turned itself off with a warning.
3. If no, do you mind sharing this file (or a stripped down version
you're okay sharing that still has these issues) along with the LaTeX
preamble?  That would be `org-latex-preview-preamble' and
`org-latex-packages-alist'.  I would like to reproduce this bug.

Previewing 2000 snippets is exactly where the new async/speedy system is
expected to shine compared to the old one.

>     2. Apparently, org-latex-default-packages-alist no longer contain
>        asmsymb and asmmath?  This change pulled the rug under me since
>        it took me quite a while to figure out why some of my formulas
>        were coloured red...

`org-latex-default-packages-alist' was modified to omit amsmath and
amssymb (among others) in preparation for a conditional export system
where required packages will be determined automatically from the buffer
text -- i.e. to avoid exactly the kind of headache you encountered.
Unfortunately this export system is not part of the patch set yet.

>     3. The image sizes of the same latex environment (e.g., \[ \]) is
>        different for different formulas.  I can send a screenshot of
>        this if required.

This is a recent regression.  Could you generate png previews by:

1. (setq org-latex-preview-default-process 'dvipng)
2. regenerating previews

and checking if this still happens?  If these look fine, this is a
dvisvgm issue and we will fix it soon.

>> If you do come across any issues, please let me know either in a reply here 
>> or
>> the org-mode matrix room. If you could also run
>> <https://gist.github.com/karthink/0ac48411a81459c0f3fd7557c4e817db> and 
>> share the
>> diagnostic info, that would be quite helpful.
>
> If needed, I can do this after reproducing (1).
>
> BTW, would it possible to arrange other latex environments (\ch{} in my
> case) to be previewed as well?  Currently, I do \(\ch{}\) but omitting
> \( \) would be nice.

Previewing unadorned LaTeX macros is officially unsupported but
partially supported in practice.  If you move the cursor over the \ch{}
and call `org-latex-preview' it should be previewed.  From that point it
should behave like a regular LaTeX fragment.  Editing it should cause
the preview to be auto-updated (If you are using
org-latex-preview-auto-mode).

Karthik