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

Tab Atkins Jr. <jackalmage@gmail.com> skreiv Tue, 03 Jan 2012 17:33:38  
+0100

> On Tue, Jan 3, 2012 at 5:40 AM, Leif Arne Storset <lstorset@opera.com>  
> wrote:
>
fantasai:
>>> 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. ^_^

SVG exhibits the same behavior as gradients in my cursory testing. My  
memory of SVG viewboxes and such is rusty enough that I don't want to  
conclude, but it does appear that SVG handling is buggy in at least Presto  
and WebKit; in Firefox 8 the SVG follows the spec, just like the gradient.  
I haven't updated my (VirtualBox) IE10 in ages, so maybe it's fixed there  
now.

So...if you handle WebKit I'll get Presto fixed. :)

-- 
Leif Arne Storset
Core Technology Developer, Opera Software
Oslo, Norway