[MPEG-OTSPEC] Is it valid to use a GSUB sequence with a leading ZWJ character please?

[William_J_G Overington]

Hello David

Thank you for replying.

> PBS had a ten-minute (or so) segment in yesterday's News Hour program 
> about glasses emoji and moving beyond the "nerd" stigma, so I'm not 
> surprised there's chatter on the Unicode list.

I have been looking through

https://www.pbs.org/newshour/show/october-13-2022-pbs-newshour-full-episode

but I could not find anything about glasses emoji.

> William, I'm curious: Why are you leading with a ZWNJ instead of 
> placing it between the to-be-ligated characters?

The reason that I am leading with a ZERO WIDTH JOINER is so as to 
produce a combining version of eyeglasses without any need for an 
additional character for COMBINING EYEGLASSES to be encoded into 
Unicode.

As I understand it, and please correct me if I have got it wrong, up 
until now the encodings approved by Unicode Inc. to produce a display of 
an emoji character that is generated from a sequence of emoji characters 
in a ZWJ-separated sequence, has been to encode a complete sequence.

Upon checking in

https://www.unicode.org/charts/PDF/U1F780.pdf

I found that LARGE PINK SQUARE is not encoded.

I may have seen it proposed somewhere.

Pink is included as one of the fifteen colours encoded in my research 
project on localizable sentences.

http://www.users.globalnet.co.uk/~ngo/localizable_sentences_research.htm

So in order to continue here I will switch from the pink that I 
mentioned previously for the eyeglasses to red.

However, in order to indicate pink rimmed eyeglasses a sequence 
including LARGE RED SQUARE and U+2B1C WHITE LARGE SQUARE could be used 
to mix the required colour.

https://www.unicode.org/charts/PDF/U2B00.pdf

So, for example, to encode a woman wearing large round red rimmed 
eyeglasses and wearing a purple hat would be to have a complete sequence 
of

WOMAN ZWJ EYEGLASSES ZWJ LARGE RED SQUARE ZWJ LARGE CIRCLE ZWJ WOMANS 
HAT ZWJ LARGE PURPLE SQUARE

and then a font would need a glyph for that image to be encoded in the 
font so that the glyph could be substituted for the sequence in the 
display.

The U+25EF LARGE CIRCLE is in

https://www.unicode.org/charts/PDF/U25A0.pdf

So, not very likely to be encoded as a recognized Unicode sequence for 
interchange.

However, if one encodes separately

ZWJ EYEGLASSES ZWJ LARGE RED SQUARE ZWJ LARGE CIRCLE

ZWJ WOMANS HAT ZWJ LARGE PURPLE SQUARE

then neither, either, or both can be used after WOMAN and a good display 
produced.

Indeed it could be that one could use

ZWJ EYE GLASSES LARGE RED SQUARE LARGE CIRCLE

ZWJ WOMANS HAT LARGE PURPLE SQUARE

using the ZWJ only at the start of the sequence.

So if several types of glasses were encoded in this way, then each of 
them could optionally be used with various emoji, not just with WOMAN.

There is then the issue of what about emoji of groups of two or more 
people and one or more of them wears glasses.

I have thought of this and have concluded that a sequence such as

ZWJ EYEGLASSES LARGE RED SQUARE LARGE CIRCLE LEFTWARDS ARROW

could be used to place the eyeglasses on the person on the left of a two 
person group, and so on, incuding diagonal arrow characters if there are 
four people in the group.

https://www.unicode.org/charts/PDF/U2190.pdf

William Overington

Saturday 15 October 2022



------ Original Message ------
From: "David Lemon" <typenerd at mindspring.com>
To: "William_J_G Overington" <wjgo_10009 at btinternet.com>; "'MPEG OT Spec 
list'" <mpeg-otspec at lists.aau.at>; "Vladimir Levantovsky" 
<vladimir.levantovsky at gmail.com>
Sent: Friday, 2022 Oct 14 At 22:51
Subject: Re: [MPEG-OTSPEC] Is it valid to use a GSUB sequence with a 
leading ZWJ character please?

PBS had a ten-minute (or so) segment in yesterday's News Hour program 
about glasses emoji and moving beyond the "nerd" stigma, so I'm not 
surprised there's chatter on the Unicode list.

William, I'm curious: Why are you leading with a ZWNJ instead of placing 
it between the to-be-ligated characters?
thanks,
David Lemon


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