RE: [css3-backgrounds] Example XV inconsistent with prose of section 3.6

> From: www-style-request@w3.org [mailto:www-style-request@w3.org] On
> Behalf Of Tab Atkins Jr.
> Sent: Monday, September 13, 2010 4:59 PM
> To: Brian Manthos
> Cc: www-style@w3.org
> Subject: Re: [css3-backgrounds] Example XV inconsistent with prose of
> section 3.6
> 
> On Mon, Sep 13, 2010 at 4:55 PM, Brian Manthos <brianman@microsoft.com>
> wrote:
> > From: Tab Atkins Jr. [mailto:jackalmage@gmail.com]
> >> On Mon, Sep 13, 2010 at 4:47 PM, Brian Manthos
> >> <brianman@microsoft.com> wrote:
> >>> http://dev.w3.org/csswg/css3-background/

> >>> 3.6  The ‘background-position’ property If only one value is
> >>> specified, the second value is assumed to be ‘center’.
> >>>
> >>> 3.10  The ‘background’ shorthand property p { background: 40%
> >>> url("chess.png") / 10em gray
> >>>        round fixed border-box; }
> >>> is equivalent to:
> >>> …
> >>> background-position: 40% 50%;
> >>> …
> >>>
> >>>
> >>> I believe this is incorrect.
> >>>
> >>> The equivalent is
> >>>         background-position: 40% center; or
> >>>         background-position: 40%;
> >>>
> >>>
> >>> Am I misunderstanding?
> >>
> >> 'center' and '50%' are equivalent in the context of a background-
> position.
> >
> > For rendering yes, for OM no...
> 
> Ah, right.  Yeah, then that example is incorrect.
> 
Why ? This module and its examples are not about the OM so I'm not clear on why
we can deem this example incorrect on OM grounds. But beyond that why is 50% not
equivalent to center in the OM ?

Received on Tuesday, 14 September 2010 01:16:09 UTC