Re: [css3-images] Features Overview

On Thu, Jul 7, 2011 at 12:51 AM, Yves Lafon <ylafon@w3.org> wrote:
> On Wed, 6 Jul 2011, Tab Atkins Jr. wrote:
>> 2011/7/6 Raphaël Troncy <raphael.troncy@eurecom.fr>:
>>> Following these
>>> discussions, we have added the following sentence to the spec:
>>>
>>> "Note that in the case of pixel-based clipping areas, application of
>>> those
>>> areas to multi-resolutions visual media is undefined."
>>>
>>> in the section 4.2.2 [2].
>>
>> What's the reasoning for making it undefined?  If it's just "it's
>> hard", then I don't find that acceptable.
>
> For percent-based clipping fragments, it makes sense at all resolutions (but
> perhaps having them integer-based is sub-optimal in many cases), but for
> pixel-based ones, it is impossible to know the intent.
> Does the format as a "default" version to apply the pixel clipping to? the
> first one? last one? bigger one? The one that fit the display?
> So it's not that it's hard, I just don't see how this could work reliably.

I agree that it's difficult to find a good answer.  If we think the
problem is essentially impossible, then we should just make it
explicitly unsupported, not undefined.

~TJ