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Re: [css3-content] Replacing ::outside with ::inside

From: François REMY <fremycompany_pub@yahoo.fr>
Date: Sun, 12 Apr 2009 21:15:42 +0200
Message-ID: <548FFAF1226446A89C47E4F38C634DC9@FREMYCOMPANY>
To: "Giovanni Campagna" <scampa.giovanni@gmail.com>, "CSS 3 W3C Group" <www-style@w3.org>
From: "Giovanni Campagna" <scampa.giovanni@gmail.com>
> 2009/4/12 François REMY <fremycompany_pub@yahoo.fr>:
>> From: "Giovanni Campagna" <scampa.giovanni@gmail.com>
>>> 2009/4/12 François REMY <fremycompany_pub@yahoo.fr>:
>>>> ::outside can be useful in other case that you
>>>> don't have mentioned.
>>>> You look at ::outside only from the border/margin
>>>> point of view, but it can have many other useful
>>>> things.
>>>> With ::outside, you can perform a break outside the
>>>> element (useful if you want to have an element on a
>>>> new line but doesn't contains the line break).
>>>> * First sample :
>>>>  <myElem>Hello</myElem>
>>>>  myElem::outside::before { content: '\A'; }
>>>> Is rendered like :
>>>>  <br/><myElem>Hello</myElem>
>>>> * Second sample :
>>>>  <myElem>Hello</myElem>
>>>>  myElem::before { content: '\A'; }
>>>> Is rendered like :
>>>>  <myElem><br/>Hello</myElem>
>>>> * Last sample :
>>>>  <myElem>Hello</myElem>
>>>>  myElem::inside::before { content: '\A'; }
>>>> Is rendered like :
>>>>  <myElem><br/>Hello</myElem>
>>> You think in terms of elements, not of boxes. If all properties are
>>> moved from "myElem" to "myElem::inside", then the visible effect of
>>> "myElem::before" is the same of "myElem::outside::before" with
>>> properties on "myElem".
>> But, it's a bad idea, I think, since I'm not putting my properties on
>> 'myElem::inside' but on 'myElem'.
>> If CSS Properties can be moved from an element to another in 
>> contradiction
>> of what the author say,
>> we're ready for so complex problems that no UA will have this right.
> I meant: "you author change you selector to include an ::inside 
> pseudo-element"

It's not always possible. If you have in your stylesheet a global rule, and 
you want a specific
outside effect, you can't eliminate your normal rule, while it's not a 
problem with ::outside.

myElem { // Defined globaly
    font-size: 7pt; line-height: 7pt

myElem#specialItem::outside { // Defined localy
    content: '\A\A';

Using myElem#specialItem::inside will result in two lines of 7pt, where with 
::outside, it's the
size of the font outside of the element (may be 12pt).

If I want the font-size of 'outside' the myElem, how can I do with ::inside 

>>>> If you have something like that :
>>>>  <box display-model="ab">
>>>>      <div display-role="a"></div>
>>>>      <div display-role="b"></div>
>>>>  </box>
>>>> And a CSS like that :
>>>>  div[display-role="a"]::outside {
>>>>      margin: 10px;
>>>>  }
>>>> It's rendered the same way as :
>>>>  <box display-model="ab">
>>>>      <div display="block"><div display-role="a"></div></div>
>>>>      <div display-role="b"></div>
>>>>  </box>
>>>> The display role of the 'inner' div is no more applyable (I think), so
>>>> it's
>>>> not in the display-model of the box element.
>>>> But it seems the spec of display-model is unclear about how the UA must
>>>> react if an element in a display-model'ed
>>>> element contains elements that does'nt enter in the model. But it's not 
>>>> a
>>>> problem of '::outside'.
>>> What? You're mixing XSL:FO (attributes as properties), Template Layout
>>> (slots), display-model...
>> Yes, but only because it's shorter to write in my mail. We can have the 
>> same
>> in pure CSS.
> Yes, but it is not "display-role", it is "position".
>> You've understood what I wanted to say.
> Not really, but I will try to guess.
>> Even if my markup is completly wrong
>> (which it is),
>> it show what I wanted to say.
>> If we have DIV::outside in a display model, it's likely to be as an 
>> element
>> was wrapping the DIV.
>> With all consequence that such a thing have. Authors expect so (or, at
>> least, me).
> And where does that ::outside get placed? In the "a" slot or in the
> "@" slot (default position inside a template element)? That is,
> ::outside is computed before or after moving elements around (for
> Generated Content and Template Layout)?
> On the other side, if you used ::inside, everything would be moved
> into the "a" slot and it would have been clear.

As if you had an annonymous <DIV> outside the element :

>>>>  <box display-model="ab">
>>>>      <pseudo:div display="block"><div 
>>>> display-role="a"></div></pseudo:div>
>>>>      <div display-role="b"></div>
>>>>  </box>

>> I find ::inside counter-intuitive, and not as useful as ::outside. But I
>> don't want to say your idea is
>> stupid, it's just not adapted to my expectation for CSS, but others 
>> people
>> can think otherly, and I
>> have respect for that, I'm just writing here to say what I think
>> personnally, that you are wrong in
>> willing to replace ::outside by ::inside.
> I instead find counter-intuitive ::outside, and find easier to
> understand to keep the inheritance in one direction-

Hum, are ::inside and ::outside incompatible ?
If not, is it possible to have both ?

We should ask some implementors... Most of the time, UA constraints solve 
these problems.
Maybe I'm wrong in defending ::outside, maybe I'm right, but I can't say it 
because I'm not implementor.

>>>> Regards,
>>>> Fremy
>>>> --------------------------------------------------
>>>> From: "Giovanni Campagna" <scampa.giovanni@gmail.com>
>>>> Sent: Saturday, April 11, 2009 7:39 PM
>>>> To: "www-style" <www-style@w3.org>
>>>> Subject: [css3-content] Replacing ::outside with ::inside
>>>>> -- background --
>>>>> This proposal crossed my mind while talking with Tab Atkins about
>>>>> ::slot in Template Layout. He wanted to allow margins, and to make
>>>>> those margins not collapse (sort of "box-sizing:margin-box"). I didn't
>>>>> like the idea, but I did think that allowing some space between
>>>>> adjacient slots and their borders may be useful. But I thought that
>>>>> this kind of space is not a margin, but rather a padding (because it
>>>>> is all around the box and doesn't collapse).
>>>>> Ok then, how to specify an external padding? You need two boxes, one
>>>>> inside the other.
>>>>> I said to myself: I need the Generated Content features... but what
>>>>> does ::slot()::outside mean? How shall I specify "display:slot"?
>>>>> This didn't look very good to me
>>>>> -- the current situation --
>>>>> The Generated and Replaced Content Module introduces the ::outside
>>>>> pseudo-elements, which wraps its superior parent and all its (in flow)
>>>>> content. This pseudo-element is not implemented in any UA I tested. In
>>>>> addition, it creates a lot of difficulty on the author side, because
>>>>> the wrapping generated box still inherits (like every other
>>>>> pseudo-element) from its superior parent.
>>>>> -- my proposal --
>>>>> Drop ::outside.
>>>>> Add ::inside, a pseudo-element wrapping all superior parent's content
>>>>> (but not ::before, ::after, ::alternate or other pseudo-elements). All
>>>>> properties apply to this pseudo-element (but their meaning is changed,
>>>>> because it is inside its superior parent like a nested <div>)
>>>>> This way, to add multiple borders to an element, you say:
>>>>> .multiple {
>>>>> border:1px solid yellow;
>>>>> }
>>>>> .multiple::inside {
>>>>> border:1px solid blue;
>>>>> }
>>>>> .multiple::inside::inside {
>>>>> border:1px solid red;
>>>>> }
>>>>> We may introduce the syntax shorthand "::inside(n)".
>>>>> Not generated ::inside elements are removed, ie if ::inside::inside is
>>>>> never referenced, ::inside::inside::inside is the same as
>>>>> ::inside::inside.
>>>>> -- use cases --
>>>>> All of ::outside, plus those case when an appropriate ::outside is not
>>>>> available, like for example ::slot.
>>>>> Giovanni
Received on Sunday, 12 April 2009 19:16:23 UTC

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