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

From: Brian Birtles <birtles@gmail.com>
Date: Mon, 28 May 2012 11:43:00 +0900
Message-ID: <4FC2E634.40200@gmail.com>
To: public-fx@w3.org
Hi Dirk,

Thanks very much for looking into this.

(2012/05/27 1:56), Dirk Schulze wrote:
> My question is the following: Every transform function (independent if translate, scale or rotate) is just a shorthand for the underlaying transformation matrix (3x3/(3x2) or 4x4).

I don't understand this point. If you have a translate of type="rotate" 
which goes from -360 to 720 it should spin three times. If you represent 
the endpoints as matrices you get no spinning at all. May this refers to 
the result of the function?

> Of course it is also possible to define the neutral element for every single transform function.

That sounds good to me. I prefer intuitive authoring to mathematical 

On that note, while we're at it, maybe we can fix scaling? Frankly, I 
think the behaviour of the example:

<rect width="100" height="100">
   <animateTransform attributeName="transform" attributeType="XML"
                     type="scale" by="1" dur="5s" fill="freeze"/>

which scales from 0->1 is counter-intuitive. I think scale from 1->2 is 
more intuitive from an authoring perspective but unfortunately that's 
not how it works for animateTransform.[1]

Maybe we can fix this for animate with transform lists?

Best regards,

Brian Birtles

Received on Monday, 28 May 2012 02:43:33 UTC

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