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Re: [css3-background] "Margins are always transparent" missing

From: Gérard Talbot <www-style@gtalbot.org>
Date: Wed, 10 Apr 2013 18:39:54 -0400
Message-ID: <b67c0ccb6d961bc1c254bc1611836e6e.squirrel@ed-sh-cp3.entirelydigital.com>
To: "Brad Kemper" <brad.kemper@gmail.com>
Cc: "W3C www-style mailing list" <www-style@w3.org>

Le Mer 10 avril 2013 17:58, Brad Kemper a écrit :
> On Apr 10, 2013, at 12:40 PM, "G¨¦rard Talbot" <www-style@gtalbot.org>
> wrote:
>
>> I still do not see where this is explicitly stated. As presented,
>> background-clip defines (can set) the background painting area; but
>> nowhere does it say that background (background color and background
>> image) - by definition - of an element is never painted into its own
>> margin area.
>
> So you want to list all the places where background DOESN'T paint?

Brad,

Where exactly have I made such request? to list all the place where
background DOESN'T paint??


> We
> could have an infinite list of things it doesn't paint or doesn't do.
> Background-clip clearly defines where it DOES paint, and defines that as
> the background painting area.
>
>> I found a 3rd place where CSS 2.1 indicates that margin area of an
>> element
>> is transparent: in this schema
>> http://www.w3.org/TR/CSS21/box.html#img-boxdim
>> we can read TM Margin (Transparent)
>
> Great. With all the places you found that, I don't see a reason to mention
> it further in a spec about backgrounds and borders (not about margins).
>
>> CSS3 box model module
>> 8. The 'margin' properties
>> http://www.w3.org/TR/2001/WD-css3-box-20010726/#the-margin
>> does not state nor suggest that the background (background color and
>> background image) of an element never paints into its own margin area.
>>

Right here, I do propose to indicate in CSS3 box model module that
background (background color and background image) of an element never
paints into its own margin area.


>> But, on the other hand, we can read that
>> "
>> The color/pattern of the element's background extends into the padding.
>> See the 'background' property.
>> "
>> CSS3 box model module, 5. The 'padding' properties
>> http://www.w3.org/TR/2001/WD-css3-box-20010726/#the-padding
>>
>> and
>>
>> "
>> The background of the element extends into the border area. See the
>> 'background' property.
>> "
>> CSS3 box model module, section 6. The 'border' properties
>> http://www.w3.org/TR/2001/WD-css3-box-20010726/#the-border
>
> Right. So there is no expectation or implication ANYWHERE that backgrounds
> paint into the margins instead of into the background painting area, as
> defined in the latest stable background spec, currently in CR.
>

Your reasoning is noted. Silence and textual absence are sufficiently
clear to you and (your assumption) should be sufficiently clear for the
spec readers. If it's not mentioned, then it's clear enough that it does
not apply, it does not paint. If it does not paint the margin area, then
it is *_not_* necessary to mention so in CSS3 Backgrounds and Borders
module and/or to mention it in CSS3 box model module. I disagree.


>> I think the clear
>>> definitions of where things in this spec do paint are sufficient.
>>
>> I disagree. Everywhere (CSS 2.1, CSS 3 Backgrounds and Borders, CSS 3
>> Box
>> model) I read, I see a statement missing or silence or a weakness in the
>> spec or a perfectible diagram. The specs (CSS 3 Backgrounds and Borders,
>> CSS 3 Box model) should promote understanding, reduce sources of
>> confusion, misunderstanding.
>
> CSS 3 Backgrounds and Borders is about Backgrounds and Borders, not about
> margins or box-model. It really has nothing to do with defining how
> margins work, or what gets painted or not by other properties, and it is
> not a proper place to reiterate random things in other specs.

There is one thing about my posts in this mailing list that you ought to
know. If test(s) submitted for inclusion into one of the several CSS test
suites at CSSWG show a misunderstanding of how a property or property
value or CSS feature work according to spec, then I will be checking
carefully to see how such a property or property value or CSS feature is
defined, explained, worded, schematically illustrated, exemplified in the
spec. And I will often follow-up and try to propose a correction or an
editorial insertion or better wording or corrected example when suitable.
I have done this many times in this mailing list.

I did not start this thread about margin area and background painting
without a triggering reason, just like that, without a
misunderstanding/confusion somewhere.

Gérard
-- 
CSS 2.1 Test suite RC6, March 23rd 2011
http://test.csswg.org/suites/css2.1/20110323/html4/toc.html

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Received on Wednesday, 10 April 2013 22:40:36 UTC

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