[MPEG-OTSPEC] Defining the text shaping working group’s scope

[Peter Constable]

I think we can agree on a definition of “plain text”, more or less, as a Unicode character sequence without any styling information. (Un-styled text accompanied by language metadata perhaps might still be considered plain text.) I would say that plain text doesn’t come with any explicit information regarding directional layout—nothing about whether it is horizontal or vertical, L or R line progression, base bidi level, etc.

But whenever plain text is _presented_, some directional information must be assumed, including at least horizontal vs. vertical and base bidi level. That might come from some application defaults or UI assumptions; or it might be inferred based on assumptions related to character properties or language metadata.

So, while such directional information is not part of plain text itself, it certainly is among the inputs that would be available to the shaping process when text is presented, whether plain text or rich text.


Peter

From: mpeg-otspec <mpeg-otspec-bounces at lists.aau.at> On Behalf Of profirst at compuserve.com
Sent: Monday, August 10, 2020 6:07 PM
To: mpeg-otspec at lists.aau.at
Subject: Re: [MPEG-OTSPEC] Defining the text shaping working group’s scope


While I do not disagree with what Peter outlined in general, I do question where the line between plaintext and rich text should lie. If it is customary and common, e.g., for a script to be written both vertically and horizontally, even though vertical text display is commonly considered to be a formatting or shaping issue, I feel it should be, for that script, part of its plaintext properties. If this makes implementation and documentation difficult, so be it.

John F.




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