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Re: Updated versions of Apple's transforms/animations/transitions proposals

From: Mikko Rantalainen <mikko.rantalainen@peda.net>
Date: Tue, 15 Apr 2008 12:31:07 +0300
Message-ID: <480475DB.6060301@peda.net>
To: www-style@w3.org
Robert O'Callahan wrote:
> On Mon, Apr 14, 2008 at 9:40 AM, David Hyatt <hyatt@apple.com> wrote:
>>> [http://www.sitepen.com/blog/2008/03/28/svg-css-animations-fisheye-fun/] 
>> No, that's not what we do.  We transition back to normal from where you
>> left off.
> 
> But that's not in the spec yet, right?
> 
> I suppose you want to look at the current value and figure out "how far
> along" the new transition you already are, and start from there, reducing
> the duration accordingly? I'm not sure how that should interact with
> transition-delay, though ... should an existing transition continue until
> the transition-delay for the new transition has expired?

To me the Safari 3.1 (win32) behavior seems like it takes current values
(as in the values used to render the view - in-flight animation) and
animates from there to the new values using the transition-delay.

This means that if the current position is not "fully zoomed" (in case
of fisheye demo), the transition (the speed of the movement/zooming) is
slower than it would be normally but it takes as long as the full
movement would take.

The Safari 3.1 behavior is probably the easiest to implement and looks
okay to me.

In short: animations always animate from currently used values to new
(target) values and the animation always takes transition-delay time no
matter how close the target the currently used value is.

> Another question is how dynamic changes to the transition properties should
> be handled. Do transitions change in-flight or do existing transitions run
> until they're done, with the new property values only applying to newly
> triggered transitions?

I've no idea how Safari does this, but if we just use the logic above,
then the currently used properties should be considered as current and
newly set properties as target. Any transition in-flight is stopped and
the only effect previously running transtion has is the currently used
property values it has caused.

The new transition goes from the currently used values to target values
using the new target transition property value.

-- 
Mikko


Received on Tuesday, 15 April 2008 09:31:54 GMT

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