[css-fonts] proposal needed for synthesizing oblique fonts in vertical text

>From the minutes of this week's telcon:

> - Discussed issue of synthesizing obliques in vertical text
>    http://lists.w3.org/Archives/Public/www-style/2013May/0153.html
>  This was a controversial topic and missing key people; no conclusion yet.

A fair amount of the discussion focused on Webkit rendering bugs and
the need to have some special form of obliquing for synthetic italics
in vertical text runs.  Whatever this proposal is, it really needs to
be spelled out.  From the talk on the call it sounded like synthetic
italic rendering for vertical text would vary based on glyph
orientation, codepoint, and font features available.

For someone implementing the CSS property 'font-style', when that is
applied to vertical text runs how are synthetic italic glyphs
rendered?  What are the conditions that affect the rendering?  Do they
affect the rendering of font families which contain italic faces (e.g.
Meiryo)?  Is the rendering behavior different based on codepoint (e.g.
emdashes) or font features (e.g. vertical alternates)?

Along with a proposal I think the use cases need to be spelled out
more clearly.  It seems to me the primary thinking behind this feature
request is "match Microsoft Word behavior" but I'd prefer to know what
the underlying usage is in actual content.  Not just example pages and
how browsers render these examples but how the desired features fit
within the typographic traditions of CJK text, given that the notion
of italics doesn't exist within CJK text historically.

For example, are there *common* usage patterns of vertical obliqued
text in Japanese print media?  I see a lot of effects applied to text
here but I can't remember when I've seen obliqued vertical text used. 
Understanding the context for which this feature is needed would allow
us to decide on the priority of including this in a spec.


John Daggett
Mozilla Japan

Received on Friday, 10 May 2013 05:00:34 UTC