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Re: [css3-2d-transforms] rotation and animation

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Mon, 23 Mar 2009 19:06:13 +0100
To: mozer <xmlizer@gmail.com>, www-style@w3.org
Message-Id: <200903231906.13650.Dr.O.Hoffmann@gmx.de>
Am Montag, 23. März 2009 geschrieben:
> 2009/3/23 Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>:
> > Hello,
> >
> > this comment applies to css3-3d-transforms as well.
> > http://www.w3.org/TR/2009/WD-css3-2d-transforms-20090320/#animation
> > http://www.w3.org/TR/2009/WD-css3-3d-transforms-20090320/#animation
> >
> >
> > In the related section about the transformation functions it is noted,
> > that for the <angle> type CSS Values and Units apply:
> > http://www.w3.org/TR/css3-values/#angles
> > This notes:
> > "Angle values should be normalized to the range 0-360deg
> > by the user agent."
> >
> > 2) authors might want to have a rotation from 30deg to 750deg,
> > what means two complete turns and not no animation,
> > or maybe from 90deg to -90deg, what is different from an
> > animation from  90deg to 270deg (what has a
> > different rotation direction too).
> > Concerning animation I think, it is pretty useful not to
> > modify the given values because this results in quite
> > different effects as typically intended by the author,
> > respectively authors cannot get the intended animation
> > effect with only one rotation function at all.
>
> So you might want to use the 'turn' unit for this purpose as specified
> in the same place ( http://www.w3.org/TR/css3-values/#angles )
>
> Xmlizer

As far as I understand the prose of the values section, the angle
itself should be 'normalised' to this range, this does not depend 
on the used unit, therefore the range 0-360deg corresponds simply 
to 0-1turn or 0-2pi or 0-400grad - it is sufficient to mention one of
those notations, because it is always the same range.
As noted too, it is/was intended for aural stylesheets, not for 
transformations or animations, therefore it cannot be a surprise, 
that new applications result in different requirements...
Received on Monday, 23 March 2009 18:08:57 GMT

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