Re: [css3-transitions] contradictory text about transitioning shorthands

On Dec 26, 2009, at 6:01 pm, L. David Baron wrote:

> I noticed that Dean and I both added text to address the issue about
> specifying handling of shorthand properties, but we did so in
> different and contradictory ways.  In
> http://dev.w3.org/csswg/css3-transitions/#the-transition-property-property-
> I added:
> #  If one of the identifiers listed is a shorthand property,
> #  implementations must start transitions for any of its longhand
> #  sub-properties that are animatable, using the duration, delay,
> #  and timing function at the index corresponding to the
> #  shorthand. 
> and in
> http://dev.w3.org/csswg/css3-transitions/#animation-of-property-types-
> Dean added:
> # a shorthand property: If all the parts of a shorthand can be
> # animated, then interpolation is performed as if each property
> # was individually specified. 
> 
> The difference is that Dean's text requires all of the parts to be
> animatable whereas mine says that any parts that are animatable
> should be animated even if others are not.
> 
> I prefer my proposal because it is more forwards-compatible:  if the
> working group turns an existing animatable property (say,
> 'text-indent') into a shorthand with some components that are not
> animatable (say, to allow 'text-indent: 5em hanging'), my proposal
> would not break existing content.

Your text is correct. For example, if the page specifies transitions of 'border',
then we'll animate border-width and border-color even though border-style
is not animatable.

Simon

Received on Sunday, 27 December 2009 05:48:39 UTC