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Re: [css-logical-properties] the 'inline-{start,end}' values for 'float' and 'clear'

From: Johannes Wilm <johanneswilm@vivliostyle.com>
Date: Wed, 11 Nov 2015 19:09:30 +0100
Message-ID: <CABkgm-Rpoct12-rDTTKeT9aL5i0H9dLRTfcoAnmJp5obz-u5dw@mail.gmail.com>
To: Brad Kemper <brad.kemper@gmail.com>
Cc: Florian Rivoal <florian@rivoal.net>, www-style list <www-style@w3.org>, Koji Ishii <kojiishi@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, Rossen Atanassov <ratan@microsoft.com>, Jonathan Kew <jfkthame@gmail.com>, "Elika J. Etemad" <fantasai@inkedblade.net>, "Tab Atkins Jr." <jackalmage@gmail.com>
Hey again,
I have looked a bit more at the different specs. And I have some questions
to better understand the concerns Brad came with.

*On Exclusions vs. Visuren*

Both the part about floats in CSS 2.1 Visuren [1] and the CSS Exclusion
spec [2] have instructions exactly how to do the placement process of the
float. As far as I can tell, the one in Visuren only works for floats that
relate to subsequent content, whereas the exclusion one is more general for
something that can be placed in some other part of the site.

Now if we want to float up, as far as I can tell, we can't really use the
rules from Visuren, because we have to influence previous content.

Then there is the section of the CSS Exclusion spec that talks about
differences between exclusions and floats [3]:


   - scope. While floats apply to content that follows in the document,
   exclusions apply to content in their containing block.
   - positioning. Floats are part of the inline flow and float on the line
   box. Authors can control how the floats move on the line box, to the right
   or to the left. By contrast, exclusions can be positioned using any
   positioning scheme such as grid layout ([CSS3-GRID-LAYOUT]), flexible box
   ([CSS3-FLEXBOX]) or any other CSS positioning scheme.
   - separation of concerns. Making an element a float determines both its
   positioning scheme and its effect on inline content. Making an element an
   exclusion only determines its impact on inline content and does not impose
   constraints on its positioning method.


The first of those three would not apply to page floats and top floats
anyway. The remaining two issues just seem to basically explain how
exclusions work and that they don't determine positioning.

Given that the point of the page float spec would be to describe
positioning and leave the description of how that influences text flow of
the content behind it to the exclusion spec, it doesn't seem like this
would make it incompatible either.

So my question now is: What difference would it make if we would try to
define the same page floats as we have them now without pointing to the CSS
Exclusion spec? Would we not have to end up having to describe much of the
same of how content flows around it as is now in the CSS Exclusion spec?

*On inline-start vs. start*

I was thinking: One solution that could work with all the models would be
if "start" and "end" simple referred to the inline directions, and one
would still have to use "block-start" and "block-end" for the block
directions. Maybe even have "start" and "inline-start".

Or would that break with the general naming scheme?

*On logical directions*

I worked some on this, but had input from Shinyu and Elika, and our
internal review at Vivliostyle made us think we are correct with the
current formulation (which also seems to be in line with what Elika and
Florian have said on the mailing list). Does anyone disagree with the
current formulation? And if yes, what do you think it should say instead?

*On the name of the spec*

I am fine with changing the name. Or keeping it. I would in general be in
favor of describing both inline floats and page floats in the same spec,
because they both use the same properties, but I don't have a very strong
opinion on this. But besides Brad and myself, what do other people think?

[1] http://www.w3.org/TR/CSS21/visuren.html#floats
[2] http://www.w3.org/TR/css3-exclusions/#exclusions-processing-model
[3] http://www.w3.org/TR/css3-exclusions/#floats-and-exclusions-differences
Received on Wednesday, 11 November 2015 18:10:06 UTC

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