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Re: [css3-transitions]

From: Dean Jackson <dino@apple.com>
Date: Tue, 31 Mar 2009 10:27:22 +1100
Cc: www-style@w3.org
Message-Id: <3449E743-E387-483A-B666-F0199CC3A745@apple.com>
To: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Olaf,

Skipping the bits about misunderstanding transitions that others have  
answered. We'll try to make it more clear in a future spec.

On 30/03/2009, at 1:15 AM, Dr. Olaf Hoffmann wrote:

> Hello,
>
> these comments are related to
> http://www.w3.org/TR/2009/WD-css3-transitions-20090320/
>
>
> 3. What means the value 'all' for the transition-property
> exactly? If we change the value of transition property for
> example in the given examples I and II. Does it apply
> to anything or nothing or only to those properties we
> add within the paranthesis, for example:
>
> div {
>    transition-property: all;
>    transition-duration: 2s, 4s;
>    opacity: 0.5;
>    left: 10ex;
>  }

It applies to all properties. What is between the parenthesis doesn't  
really matter, just like the way regular CSS works. In other words,  
apply CSS processing then see what you end up with.

> 4. About the ‘transition-timing-function’ section:
> Note, that the name of the man, who introduced
> those curves is spelled in a different way, with
> (X)HTML notation: 'B&eacute;zier' and not 'bezier'

I'll fix that, thanks.

> Is it ok to reference a wikipedia article, everyone
> can change at any time in a draft/specification?

I'll mark the link as informative.

> 5. in section 4. it is not noted, how to animate
> between keywords (they are mentioned
> in 5. too). This will be the same as for
> 'visibility'? Or are the keywords always
> converted into numbers for the current
> animatable properties (seems to apply
> only to vertical-align).

We'll have to define this for every keyword-based property. I'm not a  
big fan of these properties being animated anyway.

> About paint-server - how to interpolate
> between a radial and linear gradient?
> Is the direction vector for linear gradients
> interpolated too if different? Respectively
> the cx, cy, fx, fy, r for a radial gradient?
> What about gradientUnits, gradientTransform,
> spreadMethod, xlink:href? Or is the interpolation
> done for each pixel of the output separately?
> I think, it needs some more explanations
> how this should work.

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). For gradients, in some cases it  
might be possible to animate - if they are similar enough. They would  
have to be the same type and have the same number of stops. However,  
some people think they should just be treated like images and crossfade.


> 6. in section 5. Animatable properties
> the transform property seems to miss,
> but in 4. it is noted, that this is animatable too.
>
> Why not animation for 'display'? This is already
> now quite popular to be changed with :hover,
> I think more than for example 'visibility'

Because it is unclear what the animation actually means. It isn't  
fadin? out like opacity. Also, what values do you use as a starting  
state when display was none.

If people really want this, we can add it. For now, it's probably ok  
to fade out with an opacity transition then turn display off.

Dean
Received on Monday, 30 March 2009 23:28:07 GMT

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