- From: Xidorn Quan <quanxunzhen@gmail.com>
- Date: Sat, 24 Jan 2015 23:50:42 +1100
- To: Koji Ishii <kojiishi@gmail.com>
- Cc: Bobby Tung <bobbytung@wanderer.tw>, www-style list <www-style@w3.org>, CJK discussion <public-i18n-cjk@w3.org>
- Message-ID: <CAMdq69_8sSNgntee2KcanuYiePLvbmwTzKPfC8ZFd_yeu3=Z-w@mail.gmail.com>
I made a better version of the polyfill. You can check it in the attachment. It looks perfect on Trident, WebKit, and Blink. (Some problems with Gecko again, because of, I guess, incomplete impl of vertical text and ruby...) - Xidorn On Sat, Jan 24, 2015 at 7:03 PM, Koji Ishii <kojiishi@gmail.com> wrote: > I had an impression that someone has solved somehow and Bobby knows > that, because WebKit has implemented inter-character already. It's a > bit unfortunate to know that this wasn't solved yet. > > I agree with Xidorn that this should be solved outside of the ruby spec. > > So, both of you know the spec/algorithm to layout Bopomofo tonemarks? > I suspect still-in-work CLREQ might cover that, but if there was a > polyfill on github, that'd be a great first step. It helps authors, > and it may help possible contributors with font knowledge to > understand the necessary spec/algorithm. > > /koji > > On Fri, Jan 16, 2015 at 10:11 AM, Bobby Tung <bobbytung@wanderer.tw> > wrote: > > Hi Xidorn, > > > > I remember this issue is discussed in TPAC 2014 ruby session. Layout > Engine > > and fonts' GPOS are ok for the tone marks. > > > > But fonts vary and may take longer for penetration. I'd like to hear more > > comments from implement side for the issue. > > > > WANDERER Bobby Tung > > Sent from my iPhone. > > > > Xidorn Quan <quanxunzhen@gmail.com> 於 2015年1月16日 上午8:38 寫道: > > > > Hi, > > > > The current CSS Ruby spec requires UAs to position the tone marks in ruby > > annotation properly in the note below "ruby-position: inter-character;" > [1] > > and I was trying to implement this during the last few days. But it then > > makes me wonder whether it is worth to implement this in layout engine. > > > > The first reason made me think about this was the fact told by Bobby that > > the tone marks are always positioned in a separate column for vertical > > bopomofo in all contexts, not only when they are inside ruby annotation. > > Which means, the tone mark positioning is not limited to inter-character > > ruby; it also covers ruby and non-ruby text in vertical text. It is > > definitely what fonts should handle. > > > > The other potential problem for this is that, it will never be > interoperable > > until all UAs implement this in the same way. There are a lot of details > > need to be considered, for example, what tone marks should be > repositioned? > > Only trailing ones, or every one? What exactly position the tone mark > should > > be placed when font or font size vary? It would be hard for author to > detect > > whether a UA support the tone mark positioning, and how it is > implemented. > > > > In conclusion, I don't think it is a good idea to implement tone mark > > positioning in layout engine. It would affect interoperability and > > complicate the impls. The positioning should be handled by fonts. > > > > However, we know that no fonts seem to support this currently. They even > > display a rotated tone mark in vertical text. For this, I suggest we use > > polyfiller to do the positioning. It would be easier to implement this in > > JavaScript and DOM, a polyfiller also provides more flexiblilty for > authors > > to control over the behavior. Once the fonts start supporting this, > authors > > can simply remove the polyfiller. > > > > The attachment is a simple polyfill demo for tone mark positioning. It > seems > > to work almost fine with Trident and WebKit (with a little problem with > > Gecko, though, because of the incomplete ruby impl) > > > > - Xidorn > > > > [1]: > http://dev.w3.org/csswg/css-ruby/#valdef-ruby-position-inter-character > > > > <tone-mark-positioning.html> >
Attachments
- text/html attachment: tone-mark-positioning.html
Received on Saturday, 24 January 2015 12:51:54 UTC