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Re: [1.2T-LC] Inheritance of display-align

From: fantasai <fantasai.lists@inkedblade.net>
Date: Wed, 29 Oct 2008 11:19:44 -0700
Message-ID: <4908A940.1080704@inkedblade.net>
To: Erik Dahlström <ed@opera.com>
CC: www-style@w3.org, www-svg <www-svg@w3.org>

Erik Dahlström wrote:
> On Tue, 28 Oct 2008 21:29:56 +0100, fantasai <fantasai.lists@inkedblade.net> wrote:
> 
>> Hello SVGWG,
>>
>> Wrt http://www.w3.org/TR/SVGMobile12/text.html#DisplayAlignProperty
>>
>> The CSS Working Group has been discussing a property that does exactly
>> what's described in the SVG draft here (and also has an 'auto' initial
>> value), but we would need the property to not inherit.
> 
> It is useful for it to inherit in certain scenarios, such as when you have
> a number of 'textArea' elements that you want to have the same alignment
> on. This may be more of a problem for SVG 1.2 Tiny since it doesn't mandate
> support for CSS stylesheets and CSS selectors.

I see what you mean. You want to set it on the container and have all the
child textArea elements to inherit that setting.

In CSS we often have nested blocks, so the inheritance would really become
a problem. Setting the alignment on an element would inherit through the
entire tree. I'm guessing you aren't seeing this problem because textArea
elements directly contain only text.

> Please elaborate on why the CSSWG thinks the property should not inherit.

If you're aligning the contents of a box to the bottom, you rarely want
that alignment to nest. (Not inheriting is also consistent with the way
'vertical-align' works on table cells.)

For another thing, the values other than 'auto' have, in CSS, the side
effect of turning the block into a block formatting context. (This affects
float containment, margin collapsing, and other things.) This side effect
would then inherit through the entire element.

Imagine, for instance, that I have a page layout with several component
boxes and I want the contents of one box to align to the bottom. Inheriting
the alignment property would cause all of its contents to have strange
behavior, turning all boxes into block formatting contexts and causing the
contents of any descendant boxes to also bottom-align.

>> Also, we've heard feedback that "before" and "after" are easily confused
>> with "start" and "end". Not sure what to do about that.
>>
>> The CSSWG hasn't discussed SVG's display-align yet (I only just noticed
>> its existence on my way home from TPAC), but I think it would be a good
>> idea for us to do a little coordination here.
> 
> Coordination sounds good to me, although the SVG WG hasn't discussed it
> either yet.

So.. how'd it get into SVG 1.2 Tiny? :)

> Just curious, what CSS module wants to include this functionality?

CSS3 Box Module is the current top candidate. There's a sketch of a property
based on our discussions in Bert's draft:
   http://www.w3.org/Style/Group/css3-src/css3-box/#the-child-align

~fantasai
Received on Wednesday, 29 October 2008 18:20:42 GMT

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