math as image in Info INFO_MATH_IMAGES

[Patrice Dumas]

Hello,

In the last commits, I have implemented math as images in Info as
discussed here:
https://lists.gnu.org/archive/html/help-texinfo/2024-08/msg00001.html

The customization variable is called: INFO_MATH_IMAGES (but it may
change if you have proposals).

The result is ok, but not too good.  Indeed, for @math, the images tend
to be bigger than the flow of text, their size is not scaled correctly.
@displaymath is even worse, even though I can open the image produced
with emacs and the image is fine, it does not show up if I open the
Info file in emacs.

I tried to read a bit AUCTeX code to understand how it is done there but
couldn't really understand.

In short, I generate a LaTeX file where the math is within the preview
environment.  I run latex on it.  Then I run
 dvipng -T tight -D 600 dvi_file

One way to generate the example I setup as test, is to go to
tp/tests, and run there:
./run_parser_all.sh -dir info_tex tex_math_info_math_images

All the resulting files will be in
info_tex/raw_out_parser/tex_math_info_math_images/
In particular, the generated tex_math_info_math2img.tex LaTeX file where
the math is within the preview environment.

The test Texinfo is in tp/tests/info_tex/tex_math.texi.

-- 
Pat