Re: [css-ruby] Tone mark of bopomofo in ruby

On 01/15/2015 07:38 PM, Xidorn Quan wrote:
> 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.

FWIW, I agree with this reasoning 100%, and have been trying to convince
various people of this at the W3C meetings over the last couple years. :)

Since it's not clear in the spec, I'll take that as an issue for clarification
in the spec.

~fantasai

Received on Saturday, 7 February 2015 05:18:11 UTC