[css3-writing-modes] auto text-combine requirements

We had some discussions in Japanese ML about the requirements for auto text-combine mentioned in the current writing modes spec[1].

Whether it's required in Writing Modes Level 3 or not (could be considered in future levels) still splits. A few argued it should be, while most think it can be in future levels. But to make sure we are talking about the same thing, we had some discussions about its requirements. So, please consider this mail to help us understand the requirements better, not to push the feature into the current spec.

The feature should have two options:
1. The maximum number of characters to apply text-combine automatically
2. The class of characters to apply

For the class of characters, it's a choice between the two options:
2.1. Digits only
2.2. All narrow letters and punctuation

The definition of 2.2. should be defined in more details as we go further, but for now I think all narrow as defined in UAX#11[2], and all L*/P* categories would suffice.

The definition above matches to what Adobe In Design has today.

There's another opinion that should also be supported, which is about how to or whether to fit within almost 1em box.
3.1. Don't do anything
3.2. Allow use of half/third/fourth glyphs if available in the font
3.3. Scale to 1em box if the width exceeds some specified limits
This isn't a feature In Design doesn't support today in its auto text-combine feature today (supports 3.1. only), but we might want to, because In Design is a software for authors and authors can do anything after applying the feature, while in CSS the feature can be the one user can apply. This part I believe is still unbaked well enough and we need more discussions.

It might sound like it's still rough idea, but I hope this helps us to think about the feature.


[1] http://dev.w3.org/csswg/css3-writing-modes/#text-combine
[2] http://unicode.org/reports/tr11/


Regards,
Koji

Received on Saturday, 15 January 2011 06:49:13 UTC