Re: Tamil Brahmi Short Mid Vowels

On Windows, Khmer is rendered with a dedicated shaping engine. I don't see a need to alter that engine or integrate Khmer with USE. How we fix Tai Tham, which does go to USE is a different matter. We need to work through the solution for Tai Tham. I'm opposed to a generic and broad relaxation of virama constraints in USE as that would have impact on many scripts that currently have no requirement for virama after vowels. I'm not opposed to a new Indic Syllabic Category that has virama-like features and is allowed to follow a vowel. If we establish such a property for Tai Tham, we can consider on a case-by-case basis if any virama characters would be better served by the new property—including Brahmi.

That approach would make sense.

There are other applications besides rendering that have a need to control where  a Virama can appear and for those there is also a benefit to having such alternate contexts captured by a dedicated property.

A./

Cheers,

Andrew


-----Original Message-----
From: Unicode <unicode-bounces@unicode.org> On Behalf Of Richard Wordingham via Unicode
Sent: Tuesday, September 11, 2018 4:27 PM
To: unicode@unicode.org
Subject: Re: Tamil Brahmi Short Mid Vowels

On Wed, 29 Aug 2018 21:42:57 +0000
Andrew Glass via Unicode <unicode@unicode.org> wrote:

Thank you Richard and Shriramana for bringing up this interesting 
problem.

I agree we need to fix this. I don’t want to fix this with a font hack 
or change to USE cluster rules or properties. I think the right place 
to fix this is in the encoding. This might be either a new character 
for Tamil Brahmi Puḷḷi — as Shriramana has proposed
(L2/12-226<https://na01.safelinks.protection.outlook.com/?url=http%3A%
2F%2Fwww.unicode.org%2FL2%2FL2012%2F12226-brahmi-two-tamil-char.pdf&am
p;data=02%7C01%7CAndrew.Glass%40microsoft.com%7Cc8b7042add6043b2d79608
d6183f443b%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63672305734730
4813&amp;sdata=raIc6m1AqKNg8WMpAployLZpkk9BthumjMx%2BPUlFVNE%3D&amp;re
served=0>) — or separate characters for Tamil Brahmi Short E and Tamil 
Brahmi Short O in independent and dependent forms (4 characters 
total). I’m inclined to think that a visible virama, Tamil Brahmi 
Puḷḷi, is the right approach.

While this would work, please remember that refusing to allow a virama after a vowel also makes USE inappropriate for Khmer and Tai Tham, which use H+consonant rather than consonant+H for subscript final consonants.

Richard.