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Re: [css3-values][css3-background][css3-transforms] <position> vs. transform-origin

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Mon, 25 Mar 2013 11:11:12 -0700
Message-ID: <CAAWBYDAamPtT1O2E9r3gUfbeuaokYxui6r=04dyN_dOBHnhFeA@mail.gmail.com>
To: Simon Sapin <simon.sapin@exyr.org>
Cc: www-style list <www-style@w3.org>
On Mon, Mar 25, 2013 at 9:02 AM, Simon Sapin <simon.sapin@exyr.org> wrote:
> Kind of related to the rest of this thread.
>
> In the Level 3 spec for background-position:
>>
>> Note that a pair of keywords can be reordered while a combination of
>> keyword and length or percentage cannot. So ‘center left’ is valid
>> while ‘50% left’ is not.
>
>
> This is indeed reflected in the grammar:
> (This is only the relevant part.)
>>
>>   [ left | center | right | <percentage> | <length> ]
>>   [ top | center | bottom | <percentage> | <length> ]
>
>
> In CSS 2.1, the grammar also has this restriction.
>
>
> transform-origin however removed this restriction:
>
>>   [ <percentage> | <length> | left | center | right ]
>>   &&
>>   [ <percentage> | <length> | top | center | bottom ]
>
>
>
> Was there a reason to remove the restriction on one property but keep it in
> others?

Sigh, no, that's just what happens when you redefine the same grammar
production in multiple places - random mutations end up making them
drift.

~TJ
Received on Monday, 25 March 2013 18:12:02 GMT

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