Re: Math and the Emacs info viewer

[Gavin Smith]

On Wed, Jul 31, 2024 at 11:31:15AM +0200, Rahguzar wrote:
> Hi,
> 
> I am trying to build an info manual for the SageMath project. The manual
> functions very well except those parts which include a lot of
> mathematical notation. I want to ask if there are ways to improve the
> presentation of these parts in the Emacs viewer.
> 
> I can think of two ways:
> 
> 1. Do what Wikipedia does displaying math: i.e. convert math into images
> when the texi file is being built and include the images in the info the
> usual way. Emacs info viewer can display images so this will work very
> well especially for display math. Doing this just for the display math
> would be a big improvement.
> 
> 2. Retain information about the boundaries of math in the info document.
> These segments can be then be rendered using the preview machinery
> available in Emacs packages.
> 
> Are any of these two possible currently?

I don't believe either of those is currently possible.

The first of the two seems more practical to achieve.  The second would
require adding to the Info output format, and then the Emacs developers
would have to implement this in Emacs Info mode, which isn't guaranteed
to happen and would only be available to people once a new version of
Emacs was released.

The first method, outputting the math as an image in Info as is already
possible, would require the image to be generated.  texi2any can already
generate images for @math/@displaymath in HTML output using either latex2html
or tex4ht (accessed with the HTML_MATH customization variable).  I expect
it would be straightforward to do something similar with Info output.

(There are Texinfo manuals that use a significant amount of math formatting,
such as gnuastro[*] but I expect this does not work that well in Info output,
as you noticed.)

The only problem that I am not sure about is how the generated images would
be distributed by an automake build system.  I expect that the images could
be placed into a subdirectory and then all of that subdirectory would be
distributed.

[*] 
https://www.gnu.org/savannah-checkouts/gnu/gnuastro/manual/html_node/Convolution-theorem.html