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Re: [css3-writing-modes] The writing-mode property: existing implementations and naming

From: fantasai <fantasai.lists@inkedblade.net>
Date: Thu, 23 Jun 2011 17:40:43 -0400
Message-ID: <4E03B2DB.4040102@inkedblade.net>
To: www-style@w3.org
On 06/22/2011 06:34 PM, Sylvain Galineau wrote:
> As you know, the writing-mode property was originally defined in CSS3 Text
> many years ago [1]. It defined both block and text direction using a set of
> values like lr-tb for Latin scripts or tb-rl for Japanese. The property
> acted as a shorthand for the direction and block-progression properties.
>
> This was implemented in IE5 and has been supported since; it was,
> unfortunately, implemented without a vendor prefix.
>
> The CSS3 Writing Modes spec now redefines writing-mode to define block flow
> direction only. It also defines a writing mode as 'determined by the writing-mode,
> direction and text-orientation properties'[2].
>
> I see two issues here.
>
> First, naming. Given the scope of the feature and the module name, I would expect
> writing-mode to be a shorthand that completely defines a writing mode, not part of
> it. This seems to have been its function and intent in the original drafts. So
> I'd expect a writing-mode to be defined by, say, the block-progression and
> text-orientation properties, or using the writing-mode shorthand to set both at
> once.
>
> It just seems odd to have a property called 'writing-mode' that only defines part
> of what a writing mode is.
>
> Second, existing implementations. The writing-mode property implemented by IE5+
> has seen a fair amount of use. Not always for the exact purpose the feature was
> intended for e.g. to rotate text sideways for purely esthetic reasons. But it's
> there. During our Kyoto f2f we talked of other legacy features that were also
> been implemented and thus should be deprecated instead of redefined. Specifically,
> new semantics should use a new property name and the existing property would be
> called out as deprecated. This seems a similar scenario.
>
> Although if the new writing-mode could be a shorthand with semantics that map
> closely to its original values then it may be possible to address both issues
> at once.
>
> Thoughts ?

Filed as ISSUE-183:
   http://www.w3.org/Style/CSS/Tracker/issues/183

So, the original writing-mode property, as implemented in IE6, didn't touch
'direction', actually. Neither does the writing-mode property defined in SVG.
The definitions in the draft currently are compatible with IE6 and SVG
implementations, just not with IE8's implementation.

Given that, and given that vertical text and bidi are so rarely mixed together,
I can't imagine anyone, aside from someone writing testcases, using it unprefixed
and expecting it to change the 'direction' property. So I don't think that
changing behavior from the 2003 CR will break anything. (Given the implementation
legacy, it seems just as likely to unbreak things.)

With regards to making 'writing-mode' a shorthand that sets 'direction' per IE8,
there are two problems with this
   - it's incompatible with how 'writing-mode' is defined in SVG
   - it encourages authors to unwittingly mess with the bidi settings of the document
(These problems were explained at TPAC last year as part of the rationale for the
current syntax. [1])

So in conclusion, I don't think the property definitions should change.

I can see a reason to tweak the terminology and/or the module title, though, if you
have better suggestions.

I'm closing this issue as No Change for now. Please let me know if this is acceptable.

[1] http://www.w3.org/blog/CSS/2010/11/17/resolutions_134

~fantasai
Received on Thursday, 23 June 2011 21:41:23 GMT

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