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Re: [css3-transforms] Pseudo code for matrix decomposing

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 14 Feb 2012 13:16:32 -0500
Message-ID: <4F3AA500.6000203@mit.edu>
To: www-style@w3.org, Matt Woodrow <mwoodrow@mozilla.com>
On 2/14/12 1:03 PM, Dirk Schulze wrote:
> Hi,
>
> At the moment the CSS Transforms specification (http://dev.w3.org/csswg/css3-transforms/) provides some pseudo code to decompose 4x4 matrices. The decomposing is needed for transitions and animations of transforms. The current code uses euler angles for rotate. This might be easier to understand. Nevertheless, the WebKit implementation uses quaternion[1][2] for decomposing. Quaternion is another number system that extends the complex numbers. It helps avoiding some mathematical singularities like the hairy ball theorem[1].
>
> Should the CSS Transform specification add a normative section that implementations should use quaternion?

See thread starting 
http://lists.w3.org/Archives/Public/www-style/2010Oct/0440.html

The archive broke the threading somehow, but the response was almost a 
year later at 
http://lists.w3.org/Archives/Public/www-style/2011Aug/0652.html and 
http://lists.w3.org/Archives/Public/www-style/2011Aug/0653.html and then 
I sent http://lists.w3.org/Archives/Public/www-style/2011Aug/0665.html

It looks like after that things went silent again.  Matt, did you ever 
get a chance to compare Dean's proposed algorithm to ours?

-Boris
Received on Tuesday, 14 February 2012 18:16:59 GMT

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