740120 - text-transform:lowercase should use conditional mapping for Greek sigma

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect)

Description

[Jonathan Kew [:jfkthame]]

Applying text-transform:lowercase to Greek text currently converts Σ to σ in all cases. However, when the sigma is word-final, it should be converted to ς instead.

See http://dev.w3.org/csswg/css3-text/#text-transform, and SpecialCasing.txt in the Unicode Character Database.

In general terms, the mapping for Σ should be to σ whenever there is a following Greek letter, or when the character Σ occurs in isolation; and to ς when it is preceded by another letter but not followed by one.

(Compare also bug 307039 regarding the Greek uppercase transform.)

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: patch, use contextual lowercasing for Greek sigma

This should provide a decent approximation of the required behavior. I note that Safari already implements something similar, BTW.

We'll want a reftest to go with this...

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: reftest for contextual lowercasing of Sigma

Simple reftest for the Sigma behavior. Matches webkit behavior for these testcases.

Comment 3

[Simon Montagu :smontagu]

Comment on attachment 612511 [details] [diff] [review]
patch, use contextual lowercasing for Greek sigma

Review of attachment 612511 [details] [diff] [review]:
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I'm finding this a little hard to follow and needing to use the reftests as documentation for the code. Can you add comments specifying in which cases we're converting to final sigma and which not (as in comment 0, but in-source)?

Comment 4

[Jonathan Kew [:jfkthame]]

Attachment: patch, use contextual lowercasing for Greek sigma - enhanced comments

I've added comments to try and explain better what's being done - hope this makes it easier to follow.

Comment 5

[Jonathan Kew [:jfkthame]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2e895a0f5ccb
https://hg.mozilla.org/integration/mozilla-inbound/rev/d191234ca2fe

Comment 6

[(no longer active)]

https://hg.mozilla.org/mozilla-central/rev/2e895a0f5ccb
https://hg.mozilla.org/mozilla-central/rev/d191234ca2fe

Comment 7

[Jean-Yves Perrier [:teoli]]

I've updated https://developer.mozilla.org/en/CSS/text-transform (summary, examples and the browser compatibility table).
and added a note in: https://developer.mozilla.org/en/Firefox_14_for_developers