W3C home > Mailing lists > Public > www-style@w3.org > January 2011

Re: [css3-transform] definition of skewing

From: Chris Marrin <cmarrin@apple.com>
Date: Tue, 25 Jan 2011 09:21:57 -0800
Cc: Rik Cabanier <cabanier@adobe.com>, Alan Gresley <alan@css-class.com>, "www-style@w3.org" <www-style@w3.org>
Message-id: <D5BFA1AF-1ACB-4955-B1B0-AAC81C68ACD4@apple.com>
To: Simon Fraser <smfr@me.com>

On Jan 24, 2011, at 9:28 PM, Simon Fraser wrote:

> 
> On Jan 24, 2011, at 9:08 PM, Rik Cabanier wrote:
> 
>>> Why? Because I used generated content? Safari seems to handle it quite well.
>> What I meant is that a 3d transform is conceptually harder than a simple rotate.
>> 
>>> Does the perspective value cause the vanishing points to either come 
>>> closer together or further away from each other or is a new perspective 
>>> point introduced?
>> I think that authors don't think about this when creating content. They just manipulate the graphics so they look what they have in mind.
>> I might be slightly biased because our products have the rotate(x, y) feature and I can see it's being used all the time...
>> (ie in the attached file, the green animation has this effect applied.)
>> 
>>> To demonstrate how your mathematical view is different from my visualization view.
>>> <http://css-class.com/test/css/3/transform-color-cube.htm>
>> :-) 
>> 
>>> Does example 1a in the below demo meet your requirement? please view in Safari.
>>> <http://css-class.com/test/css/3/transforms-rotate-skew.htm>
>> It's close, but not quite the same.
>> I posted an example here:
>> http://mobiletest.host.adobe.com/csstest/skull.html
>> The flash rendering is using rotate(x,y) while the html version uses rotate.
>> 
>> Also, looking at the working draft, rotateX/Y are not listed: http://www.w3.org/TR/2009/WD-css3-2d-transforms-20090320/
> 
> rotateX/rotateY are considered 3D transforms: <http://www.w3.org/TR/css3-3d-transforms/>

But I think his rotate(x,y) function is not the same. The one in the spec rotates about the X and Y axes. His function would apply a rotation to the X and Y vectors of a 2D matrix. That makes calling it "rotate" too confusing. But beyond that, I don't think it's an important enough transformation to warrant a function.

-----
~Chris
cmarrin@apple.com
Received on Tuesday, 25 January 2011 17:23:00 GMT

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