W3C home > Mailing lists > Public > www-style@w3.org > March 2009

Re: [css3-transitions]

From: Dean Jackson <dino@apple.com>
Date: Tue, 31 Mar 2009 12:22:51 +1100
Cc: www-style CSS <www-style@w3.org>
Message-Id: <063F9E0C-D268-4B26-850B-8B07B5C1CAAB@apple.com>
To: Brad Kemper <brad.kemper@gmail.com>

On 31/03/2009, at 11:29 AM, Brad Kemper wrote:

> > It's still up in the air how gradients should transition. For  
> regular images, like background, they should probably crossfade  
> (with the opacity used in the transition calculated by the timing  
> function.. and the reverse for the outgoing image).
>
> Or other transition effects, such as checkerboard, barn-door, shape- 
> zoom, etc.?

I think this is getting fairly advanced, but it might be possible.  
However, I don't think we need to specify it in the first version.

Here's a suggestion for how it could work:

transition-image-effect: IDENT

The thing is that once you start giving authors this much power they  
want to control it. For example, OSX has a ripple-like effect if you  
drop a dashboard widget. Authors may want to control the amplitude of  
the ripple, or speed of the wave, etc. How do you pass parameters in?  
Lots of other properties? Function syntax?

Again, let's stick with cross-fading for now and look at this later.


> If images can fade from one to the other to represent multiple  
> states that wouldn't normally wouldn't be represented in CSS (a list  
> item marker would normally only have one url() at a time), then  
> let's go hog wild with how to represent the midway states of other  
> binary properties:
>
> Visibility could fade as though it represented opacity of 0 or 100%.
>
> 'display:none' could be treated as though it was equivalent to  
> 'width:0; height:0; opacity:0;'.
>
> To transition between 'position:static' and 'position:relative', you  
> could immediately switch the static to 'position:relative; left:0;  
> right:0; top:0; bottom:0; z-index:0;'.

Unfortunately this isn't so easy. Why should display:none have width: 
0? What if width is specified elsewhere? What happens to layout? What  
about the stacking contexts you may add with these automatic  
transitions?

I think it's better to start simple. The effects you describe can be  
performed now with a little extra script.

Dean
Received on Tuesday, 31 March 2009 01:23:45 GMT

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