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Re: [css3-transforms] neutral element for addition - by animation

From: Dirk Schulze <dschulze@adobe.com>
Date: Mon, 4 Jun 2012 21:50:59 -0700
To: Brian Birtles <birtles@gmail.com>
CC: "public-fx@w3.org" <public-fx@w3.org>
Message-ID: <FA552DB8-B1A3-41A7-9B64-6A6BD2F3BDAD@adobe.com>
Hi Brian,

On Jun 4, 2012, at 6:21 PM, Brian Birtles wrote:

> (2012/06/05 4:06), Dirk Schulze wrote:
>> On Jun 4, 2012, at 11:58 AM, Cyril Concolato wrote:
>>> This thread is just too long for me at the moment, but I repeat
>>> what I said. I think that the neutral element for by animations
>>> should be the identity matrix.
> 
> I agree.
Even so. I strongly suggest reading the whole thread. Otherwise we run in a circle. I explained why it is not the identity transform currently in my last comment. Olaf did it before. And Cyril meant something different than you, because he agrees to the initial value of 0 for scale on by animations as neutral element, but because of different reasons.

You propose to use the identity matrix as underlying value instead. This would mean that for the following example:

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
 <rect width="100" height="100" transform="scale(1)">
   <animateTransform attributeName="transform" type="scale" by="1" dur="3s"/>
 </rect>
</svg>

we get an animation from scale(1) to scale(2). That is something that most authors may assume at the beginning. And I would agree that we should go that way. But it is against the definition of SMIL animation. See previous mails.

> 
>> But that does not prevent us from changing it. Would just be one more
>> difference to SMIL :).
> 
> I'm quite ok with that. Let's do it right for <animate 
> attributeName="transform" ...> and discourage using <animateTransform> 
> in future.
> 
> Best regards,
> 
> Brian Birtles
> 

Greetings,
Dirk
Received on Tuesday, 5 June 2012 04:51:32 GMT

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