1085183 - (ruby-overhang) Implement overhanging ruby

Status: NEW

(Core :: Layout: Ruby, defect)

Description

[Xidorn Quan [:xidorn] UTC+11]

It is an optional feature, but since JLREQ mentions the use case, and other UAs have supported this effect, we may want to implement as well.

Comment 1

[Xidorn Quan [:xidorn] UTC+11]

A note here. Relevant document:
http://www.w3.org/TR/jlreq/#adjustments_of_ruby_with_length_longer_than_that_of_the_base_characters

There are roughly three main styles of ruby overhanging:

The first one is the most complicated one. It allows annotation to overhang up to the full-width of an annotation character if the adjacent character is a kana or a puncuation. (There are some further details, though) And if two annotations are touched because of the overhanging, one em space should be inserted before the latter annotation.

The second one is overhanging any adjacent character up to half-width of an annotation character. This is what implemented in WebKit/Blink. There is an error in JLReq which announces it can overhang up to full-width. [1]

The third one is never overhanging any character. This is our current behavior, as well as Trident.

[1] https://lists.w3.org/Archives/Member/member-japanese-layout-ja/2015Jan/0000.html