Georgian uppercase transforms fail #30

This issue is applicable to modern Georgian.

Dedicated mtavruli Unicode characters were only introduced in Unicode v11 (2018). Prior to that, authors had to use special fonts with the mkhedruli code points in order to write mtavruli letters, and CSS text-transforms (ie. to uppercase) had no effect. Unicode 11 introduced not just the new characters, but also mappings from mkhedruli (lowercase) to mtavruli (uppercase).

The original GAP

This was particularly problematic in pages that are translations of content that was originally in the Latin script, and which applied CSS text-transforms to some text. Prior to Unicode11, there was no need to remove the CSS styling from translated pages, since no text-transform had any effect. Post Unicode 11, however, the mapping to mtavruli characters was being applied and tends to produce tofu.

This situation lead Chrome and Firefox in 2018 to add workarounds to their browsers that prevented the conversion of Mkhedruli characters to Mtavruli when using CSS text-transform:uppercase. (Conversion from Mtavruli to Mkhedruli works, however.) This workaround is still in place, even though there is now better support for Mtavruli in pre-installed fonts on both the Mac and Windows platforms.

Note that Mtavruli is only used for ALL CAPS typography, and is not used at the beginning of a sentence or for proper nouns, so this only affects the uppercase value of text-transform.

css-text-3 describes the text-transform property. There is no information specifically relating to Georgian.

In summary, WebKit browsers support Georgian case conversion, but Gecko and Blink browsers don't.

For information about font support for Mtavruli characters, see #19

Priority

Basic priority applied because, although Mtavruli characters are only used for ALL CAPS, there is no reason that Georgian users should be forced to use uppercase code points rather than using a transform.

Tests

i18n test suite, Georgian mkhedruli/mtavruli

Interactive test: , text-transform:uppercase produces mtavruli consonants for mkedruli characters regularly used by the Georgian language.

Action taken

Browser bug reports: Gecko • Blink • Blink

Outcomes

Gecko now supports Georgian uppercase conversion, as well as WebKit. Blink browsers still fail.

• Gecko: ✅
• Blink: ❌
• Webkit: ✅