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Re: [css3-background] background-shorthand and its background-clip side-effect

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 5 Mar 2010 10:15:20 -0600
Message-ID: <dd0fbad1003050815q47888477xc4dcfdd0c80c65eb@mail.gmail.com>
To: Brad Kemper <brad.kemper@gmail.com>
Cc: Sylvain Galineau <sylvaing@microsoft.com>, fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>, Arron Eicholz <Arron.Eicholz@microsoft.com>, Brian Manthos <brianman@microsoft.com>
On Fri, Mar 5, 2010 at 10:00 AM, Brad Kemper <brad.kemper@gmail.com> wrote:
>
> On Mar 5, 2010, at 7:52 AM, Tab Atkins Jr. wrote:
>
>> On Thu, Mar 4, 2010 at 2:36 PM, Brad Kemper <brad.kemper@gmail.com> wrote:
>>> On it's own it not too bad, but as a way to disambiguate between two
>>> subproperties in in 'background' that take the same values, it is
>>> inconsistent with any of the proposals to disambiguate <bg-position> and
>>> <bg-size>.  I don't think this serves authors as well, ultimately, who
>>> currently have no expectations of how this disambiguation should occur.
>>
>> The position/size disambiguation needs to be more complex, because
>> there is added possibility of confusion.  Both properties can have one
>> or two value, so if you see two lengths next to each other, you can't
>> tell whether it's just one property being specified or two being given
>> a single value.  Similarly, if you see 3 values you can't tell which
>> property gets a pair and which gets a singleton.
>
> You can if you use the slash the way I was suggesting, which would also be consistent between disambiguating BOTH the <bg-position>/<bg-size> combinations AND the <bg-origin>/<bg-clip> combinations in the same ways. Thus, the position/size disambiguation does NOT need to be more complex than the origin/clip disambiguation. They can both be simple, with a single slash providing a reference point for disambiguation.

What I meant is that you don't *need* a slash in the origin/clip
situation, since you can rely on a simple ordering.  That's not
sufficient for position/size.  Ordering-based disambiguation is used
much more commonly throughout CSS, and so should be relied on when
possible.

~TJ
Received on Friday, 5 March 2010 16:16:18 GMT

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