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Re: [css3-images][css3-background] Specify "CSS View Box" in B&B

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 3 Jan 2012 08:33:38 -0800
Message-ID: <CAAWBYDCCkpY=mXk9QfHkB5Fgvwv=fyKFVv5tpQsgVEinBpdkew@mail.gmail.com>
To: Leif Arne Storset <lstorset@opera.com>
Cc: fantasai <fantasai.lists@inkedblade.net>, Brad Kemper <brad.kemper@gmail.com>, "bert@w3.org" <bert@w3.org>, "www-style@w3.org" <www-style@w3.org>, Rafal Chlodnicki <rchlodnicki@opera.com>
On Tue, Jan 3, 2012 at 5:40 AM, Leif Arne Storset <lstorset@opera.com> wrote:
> Since background-origin is not specified in this example, the BPA is the
> padding box, which is 100px tall. Thus, concrete object height = padding box
> height.

Yes, your analysis is correct.


>> Leif, would you mind reviewing http://dev.w3.org/csswg/css3-images/ and
>> letting me know if there's still an issue? If so, I'm not entirely clear
>> on what it is...
>
>
> We need to decide whether we want to keep the currently-specced behavior (if
> my understanding of it is correct) and file bugs against WebKit, Presto and
> Trident, or whether we only file bugs against Gecko after changing 5.3 so
> that the missing dimension is calculated using the specified dimension and
> the aspect ratio of the default object size.
>
> I recommend changing the Images spec to match the majority of
> implementations; it makes gradients behave quite similarly to raster images,
> and if the author really wants 100% in one dimension he or she can just
> specify that.
>
> The downside is that this would override the B&B spec [3]. Also, it could be
> argued that keeping the spec as it is is more logical; if gradients have no
> intrinsic ratio, why pull one from the BPA?
>
> [0] http://lists.w3.org/Archives/Public/www-style/2011Feb/0170.html
> [1] http://lists.w3.org/Archives/Public/www-style/2011Feb/0229.html
> [2] http://dev.w3.org/csswg/css3-images/#object-negotiation
> [3] http://dev.w3.org/csswg/css3-background/#auto
> [CSS3BG] http://www.w3.org/TR/2011/CR-css3-background-20110215

Note that gradients aren't meant to be similar to raster images, but
rather to vector images.  As such, their behavior matches that of an
SVG image without intrinsic dimensions or ratio (or rather, it would
if various browsers like WebKit weren't buggy as hell with SVG).  We
can't change 5.3 without changing the existing behavior for SVG as
well.

I'm willing to patch WebKit into matching the spec and not giving
gradients an intrinsic ratio.  I also suspect that IE10 matches the
spec, since Brian is such a stickler for detail. ^_^

~TJ
Received on Tuesday, 3 January 2012 16:34:26 GMT

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