Traditional Mongolian is not shown properly

[ash-f]

The orientation of characters should be upright. (and should be continuous in the same sentence.)
Also the traditional Mongolian is the only language that lines flow from left to right in vertical writing.

[ash-f]

Horizontal text with OpenType>Initial Forms enabled seems to work as a workaround.
(But partially incorrect. some characters seems to have different shape if they are not at the first in the sentence.)
Then rotating the text box can make it look like a vertical text.
Now, the problem remains is the flow direction of lines...

[ash-f]

I think these OpenType's character position attribute in traditional Mongolian have to be set automatically.
(Can be judged by simple rules for which form should be used I guess)

Initial Forms
Medial Forms
Final Forms
Isolated Forms

P.S.
VectorStyler shows "Medial Forms #2" in the OpenType menu and Final Forms is missing.
In Affinity Designer, it's the opposite - there's Final Forms and Medial Forms #2 is missing.

[VectorStyler]

@ash-f I open a bug on this one. But the fix will not make it into the next release.

[ash-f]

@vectoradmin Yes, this isn't necessary right away.
But I noticed that transitional Mongolian is being requested in other graphic apps.
And not even Adobe can handle it properly.

I think MS Word and LibreOffice could be the only app that can handle transitional Mongolian.

[ash-f]

Here's the OpenType features for West-Asian(and I think traditional Mongolian is included)
https://en.wikipedia.org/wiki/List_of_typographic_features#Features_primarily_intended_for_or_exclusively_required_by_West-Asian_(Semitic,_Arabic)_and_other_cursive_scripts_or_fonts

[ash-f]

These are the Open Type features Illustrator recognizes on the transitional Mongolian font.

Initial Forms
Isolated Forms
Medial Forms
Required Ligatures
Terminal Forms
Vertical Writing

[ash-f]

@vectoradmin Inkscape seems to handle traditional Mogolian properly.
It has left to right mode in vertical writing. also it handles continuous character(cursive) automatically by using the OpenType feature.
You may be able to refer their code/logic since it's a opensource.