Hi Juan Manuel,

Thank you for writing this, which is the clearest explanation I have seen
of the advantages of LuaLaTeX/XeLaTeX. I have been using LaTeX for nearly
30 years, but stopped using it intensively every day when pdfLaTeX was
still the bleeding edge. When I started again in the last couple of years,
it has been a bit confusing to understand why and what all these different
versions are. These days I use LuaLaTeX as well, but most of the documents
I process are exported from Org-mode.

Best,
--Diego


On Mon, Apr 5, 2021 at 10:49 PM Juan Manuel Macías <maciaschain@posteo.net>
wrote:

> Hi all,
>
> There have been some threads recently about exporting to LaTeX, but I
> think something that I consider interesting for novice Org/LaTeX users
> has not been commented: the choice of the TeX engine. I think this is
> important because although people often say they "use LaTeX", what they
> actually use is TeX via the La-TeX format. What TeX engine to choose? I
> would dare to say the following: unless you want to maintain some
> backward compatibility with old documents, I highly recommend using
> LuaTeX or XeTeX, especially LuaTeX. Although pdfTeX is very popular
> among average or veterans LaTeX users, I think using it nowadays doesn't
> make much sense (IMHO). LuaTeX is the natural evolution of pdfTeX and
> adds the great advantage of accesing the TeX internals through Lua
> scripting.
>
> (What follows is specially intended for those Org users who haven't used
> XeTeX or LuaTeX yet).
>
> LuaTeX and XeTeX are *100% Unicode-based* and you can use your system
> fonts (open type, true type, etc.) in your documents in a simple way
> through the fontspec (https://www.ctan.org/pkg/fontspec) package, which
> provides a very neat interface and manages all OpenType features (LuaTeX
> and XeTeX use HarfBuzz as otf rendering engine). In LuaTeX also you can
> use any font that is not installed in your system: just indicate the
> path to the fonts files. This is very useful to test new fonts without
> installing them... In all modern word processing systems the user has
> always been able to pick a font easily, and that has been historically
> quite complex, hard and complicated in the (La)TeX ecosystem.
>
> For example, if we want to use globally the Palatino Linotype family in
> our LuaLaTeX document:
>
> \setmainfont{Palatino Linotype}
>
> We can add some OpenType features, like old style numbering:
>
> \setmainfont{Linux Libertine O}[Numbers=LowerCase]
>
> And if we want to use another font for italics, with certain properties
> (color[1] and scaling):
>
> \setmainfont{Crimson}
> [Numbers=Lowercase,
> ItalicFont=MinionPro-It.otf,
> ItalicFeatures={Color=red,
> Scale=MatchLowercase}]
>
> ([1] Requires the xcolor package)
>
> We can also define our own family with its properties (for example, with
> upper case numbers and letters tracking):
>
> \newfontfamily\myfamily{crimson}
> [Numbers=Lining,LetterSpace=3.0]
>
> Furthermore (for more advanced users), in LuaTeX we can define new
> opentype features on the fly, both positional and of substitution (as
> long as the typeface includes the glyphs needed to replace). For
> example, if I use the Crimson typeface, a contextual substitution for
> character Q + u can be defined, by including some Lua code through the
> LuaTeX primitive `directlua':
>
> \directlua{
>    fonts.handlers.otf.addfeature{
>     name = "mycontextual",
>     type = "chainsubstitution",
>     lookups = {
>       {
>         type = "substitution",
>         data = {
>           ["Q"] = "Q.alt01",
>         },
>       },
>     },
>     data = {
>       rules = {
>         {
>           after  = { { "u" } },
>           current = { { "Q" } },
>           lookups = { 1 },
>         },
>       },
>     },
>   }
> }
>
> ... And add anywhere in the text:
>
> \addfontfeature{RawFeature=+mycontextual}
>
> If I had to choose, finally, between XeTeX and LuaTeX, I would choose
> LuaTeX, for things like these and many other reasons. In addition, there
> are emerging cool new packages that only work with LuaTeX.
>
> Anyway, XeTeX is another very good option too, especially for users who
> prefer something that works more "out of the box" and is less esotheric
> than LuaTeX.
>
> To export to PDF always with LuaTeX we can put in our ~ /.emacs:
>
> (setq org-latex-pdf-process
>       '("lualatex -shell-escape -interaction nonstopmode -output-directory
> %o %f"
>         "lualatex -shell-escape -interaction nonstopmode -output-directory
> %o %f"
>         "lualatex -shell-escape -interaction nonstopmode -output-directory
> %o %f"))
>
> Or with latexmk, which will take care of compiling as many times as
> necessary for indexes, bibliographies, etc .:
>
> (setq org-latex-pdf-process
>       '("latexmk -lualatex -e '$lualatex=q/lualatex %%O -shell-escape
> %%S/' %f"))
>
> Best regards,
>
> Juan Manuel
>
>