Re: [css3-transitions] transitioning a shorthand

On Jul 6, 2010, at 10:56 PM, Simon Fraser wrote:

> On Jul 6, 2010, at 10:33 PM, Tab Atkins Jr. wrote:
> 
>> On Mon, Jul 5, 2010 at 9:14 AM, Simon Fraser <smfr@me.com> wrote:
>>> Note that the spec currently says:
>>> 
>>> "a shorthand property: If all the parts of a shorthand can be animated, then interpolation is performed as if each property was individually specified."
>>> 
>>> but I don't think this is correct.
>>> 
>>> The way WebKit implements this is if *any* part of a shorthand can be animated then it will be, and this works both ways.
>> 
>> I thought we were making all properties animateable, so that
>> properties that didn't have special animating behavior just
>> floor/ceiling'd their transition function (I forget which way we
>> decided right now).
>> 
>> In that case, the distinction is irrelevant, and in fact the line
>> itself is no longer needed.
> 
> I think that's orthogonal to this question. The issue with shorthands, I think, is whether the author expects individual properties to animate when shorthands are used in transition-property, and when the individual properties as changed via shorthand rules.

I would. If I have 'margin' as the transition-property, and then I change 'margin-top', then it should animate. The other margin would also be animating in theory, but with the same beginning and ending values, who would know? If I did it the other way around, and had 'margin-top' as the transition-property, and then changed 'margin' to something that was different on all four sides, then I think only 'margin-top' would animate, but the other margins would just jump instantly to their new values.