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Re: [css3-transitions] [css3-animations] API for testing transitions and animations

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 14 Feb 2012 14:01:17 -0500
Message-ID: <4F3AAF7D.6030704@mit.edu>
To: Aryeh Gregor <ayg@aryeh.name>
CC: public-css-testsuite@w3.org
On 2/14/12 1:56 PM, Aryeh Gregor wrote:
> On Tue, Feb 14, 2012 at 1:26 PM, Boris Zbarsky<bzbarsky@mit.edu>  wrote:
>> Say you have a transition from "width: 100px" to "width: 200px" that's
>> supposed to take 1s.  When you do whatever you think will trigger the
>> transition you start a 500ms timer.  When that timer fires, you examine the
>> width of the element.  It should be 150px, to some tolerance.
>> If desired, random error can be reduced somewhat by doing this whole
>> operation multiple times.
>> The question is what the tolerance should be.  And that depends on what the
>> random and systematic errors involved are, what their typical sizes are, and
>> which of them are allowed per spec.
> If there are tight guarantees in practice on when the timer fires,

Which timer?  The setTimeout timer, or the animation one?

> If there aren't tight guarantees in practice, and the timer will often
> decide to fire whenever it feels like it in real browsers, then pages
> can't depend on the behavior.

The point of this exercise is to prevent having to write a 
labor-intensive manual reftest....

> In any event, we should be able to test this directly, not with a new API.

Yes, that was my point.

>> Obviously for colors that doesn't work, unless you use SVG to somehow
>> composite things together and use feColorMatrix to map differences to
>> something noticeable.
> Or you can have it flip back and forth between the two pages every few
> tens of milliseconds.  Then it will flicker if there are any
> differences.  This would work best with animations that repeat
> indefinitely, of course.

Yes, that would work.  The big issue is the manual testing needed.

> Sure.  That's also an example of something that animated reftests could handle.

Yes, agreed, modulo the usual caveat.

Received on Tuesday, 14 February 2012 19:01:57 UTC

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