[NTG-context] About vertical typesetting in ConTeXt

[Hans Hagen]

On 6/10/2020 7:49 AM, Jairo A. del Rio wrote:
> Hi list! I'm curious about vertical typesetting in ConTeXt. As far as I 
> know, LuaTeX supports four text directions, but LTL is broken for Manchu 
> script (letters are displayed unjoined in LTL mode) and LuaMetaTeX does 
> not support vertical directions anymore, at least as primitives.
> 
> I found the following solution:
> 
> https://tex.stackexchange.com/a/140972/193767
> I reproduce the code (in XeLaTeX), just in case
> 
> |% !TEX TS-program = 
> xelatex\documentclass{scrartcl}\usepackage{fontspec}\newfontfamily{\dcw}[]{DaicingWhite}%\begin{document}\noindentLine 
> above\\% to demonstrate that the lines are being stacked as 
> normal\rotatebox{-90}{%\XeTeXupwardsmode1\\% successive lines will be 
> stacked upwards instead of downwards\begin{minipage}{4em}% this will be 
> the vertical length of the Mongolian section{\dcw% Font: Daicing White1 
> ᠮᠠᠨᠵᡠ ᡤᡳᠰᡠᠨ\\% direct Unicode input of Manchu letters2 ᠮᠠᠨᠵᡠ ᡤᡳᠰᡠᠨ }% 
> End font\end{minipage}\XeTeXupwardsmode0 }% End rotatebox\noindentLine 
> underneath \end{document}|
> 
> 
> and I see XeTeX uses the primitive |\XeTeXupwardsmodeand some other 
> tricks to get the proper display of Manchu text, so maybe MKII can do 
> the magic using XeTeX as an engine. How would one use ConTeXt MKIV for 
> this task? Is it possible to emulate \XeTeXupwardsmode in ConTeXt as a 
> first step? Thank you very much.
I admit that I have no clue about what xetex does in that departmentbut 
you're right that in lmtx the vertical directions are not supported. The 
main reason is that it didn't really integrates well in the way pages 
are constructed.

Vertical typesetting (afaiks) involves two things: one character wide 
columns and rotated glyphs. The first can be handled by the macro 
package and the second by a combination of engine and macro package.

Already for quite a while there are the basics for a more advanced 
vertical subsystem but it's typically one of these things that I explore 
and then set aside till some users show up who need it and are willing 
to spend time on discussing and testing intertfaces. After all, most of 
this tex stuff is kind of a hobby and it's easy to find new interesting 
experiments.

Anyway, you can get some ideas in chapter 6 of:

   http://www.pragma-ade.com/general/manuals/followingup.pdf

but as said, probably no one ever read that. The question isnot so much 
if it can be done, but how to integrate it.

(There's more stuff waiting for being used but we leave that for users 
to run into and demand support for.)

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------