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

I've wrote a blog post here[1] that lists up issues of top-edge-to-right slant, and I will be working with fantasai for the text to propose.

Regarding the use cases, as written in the post above, there are a good number of real use of Italic Latin text to appear in vertical flow in Japanese publications, and making them UA dependent is very likely to break them.

You're right that italicized Japanese characters are much less common, but they still exist. Also the nature of Unicode not being able to classify if a character is Latin or Japanese will give much more common use cases.


-----Original Message-----
From: John Daggett [] 
Sent: Thursday, May 09, 2013 10:00 PM
Subject: [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

>  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 21:58:00 UTC