Re: [css3-transitions] Transitioning shorthands

On Apr 4, 2011, at 9:07 AM, Sylvain Galineau wrote:

> In 2.1 The transition-property Property [1], transitioning shorthands is defined thus:
> 
> # If one of the identifiers listed is not a recognized property name or is not an 
> # animatable property, the implementation must still start transitions on the 
> # animatable properties in the list using the duration, delay, and timing function 
> # at their respective indices in the lists for 'transition-duration', 
> # 'transition-delay', and 'transition-timing-function'. In other words, unrecognized 
> # or non-animatable properties must be kept in the list to preserve the matching of indices.
> 
> Thus, when transitioning from:
> 
>     background: url(a.png) repeat-y 20px 0px;
> 
> To:
> 
>     background: url(b.jpg) repeat-x 0px 40px;
> 
> I would expect the background-position sub-property to transition while background-image and
> background-repeat do not since they are not animatable.
> 
> In '6. Animation of property types' [2], we have :
> 
> # a shorthand property: If all the parts of a shorthand can be animated, 
> # then interpolation is performed as if each property was individually 
> # specified.

I believe this should be "any", not "all".

> 
> Which could be interpreted as saying that shorthands only animate if all their parts can
> animate. 
> 
> My understanding is that 2.1 (transition the animatable parts, keep the rest in their initial
> state) is the intended behavior. Firefox and Chrome agree.
> 

Agreed.

Simon