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Re: [css3-transitions] transitioning to/from auto value

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Wed, 28 Apr 2010 09:55:17 -0400
Message-ID: <4BD83E45.8010708@mit.edu>
To: Perry Smith <pedzsan@gmail.com>
CC: Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>
On 4/28/10 9:35 AM, Perry Smith wrote:
>> For example, if a browser batches up style changes and processes the batch all at once, the transition will start partway through the processing of the batch.  At this point, some of the pending style changes have been processed and some haven't; which ones have or haven't may well be effectively random.
>
> In this scenario, even without transitions wouldn't there be the possibility that the attribute that was just set to auto to bounce around?  It seems like users would not like that either.

I'm not sure I follow.  What issue do you see without transitions?

_With_ transitions, the issue I'm concerned about is basically this:

   div {
     transition: height 1s;
     height: 0;
     width: 100px;
   }

Then I have:

   <div id="x">This is some text that is 150px wide</div>

and this script:

    var div = document.getElementById("x");
    div.style.height = "auto";
    div.style.width = "200px";

What height should the div transition to and why?  Note that in current 
UAs those two style changes can be processed in arbitrary order; the 
page can't detect the difference.

> Seems like there is a middle ground somewhere.  Define the simple case where only one attribute is in flux at the time and it is going from fixed to auto or auto to fixed and declare that anything more complex the author will get a strongly worded letter from the UN :-)

That is _exactly_ the reverse-engineering and author-complaint hellhole 
that's not acceptable, actually.  We already have this with first-line, 
and it's just broken beyond belief.

-Boris
Received on Wednesday, 28 April 2010 13:55:53 GMT

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