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Re: CSS 2D transforms rotate with center point

From: Simon Fraser <smfr@me.com>
Date: Fri, 11 Jun 2010 10:03:38 -0700
Cc: public-fx@w3.org
Message-id: <0AD04B7C-89F2-45EB-A469-84CE3CB1F294@me.com>
To: Dirk Schulze <vbs85@gmx.de>
On Jun 11, 2010, at 1:10 AM, Dirk Schulze wrote:

> Am 11.06.2010 07:43, schrieb Dirk Schulze:
>> Hi,
>> 
>> is it possible to extend rotate(<angle>) in the CSS 2D transforms spec [1] with two optional arguments for the center of the rotation cx and cy to rotate(<angle> [, <number>, <number>])? This would make CSS transforms more compatible with SVGTransforms [2].
>> 
>> Dirk
>> 
>> [1] http://dev.w3.org/csswg/css3-2d-transforms/#transform-functions
>> [2] http://www.w3.org/TR/SVG11/coords.html#TransformAttribute
>> 
> <number> is of course the wrong value here, <translation-value> is better. So the definition for rotate would be:
> 
> rotate(<angle> [, <translation-value>, <translation-value>])
> 
> if no cx or cy is specified, the rotation is about the origin of the element. Using cx, cy would result in translate(cx, cy) rotate(<angle>) translate(-cx,-cy).

It seems pretty arbitrary to just supply an origin for rotation. Why not for scale() and skewX()/skewY()?

Also, to be consistent, we'd have to allow a 3-axis origin for rotate3d(), rotateX(), rotateY() and scale3d() as well.

Simon
Received on Friday, 11 June 2010 17:04:40 GMT

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