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

From: Brad Kemper <brad.kemper@gmail.com>
Date: Wed, 10 Apr 2013 14:58:03 -0700
Message-Id: <CE7AB821-27B0-47E3-9EB1-7EDD198765B9@gmail.com>
Cc: W3C www-style mailing list <www-style@w3.org>
To: "www-style@gtalbot.org" <www-style@gtalbot.org>
On Apr 10, 2013, at 12:40 PM, "G¨Śrard 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? 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.
> 
> 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. 

> 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.
Received on Wednesday, 10 April 2013 21:58:35 UTC

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