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Re: [css3-transforms] transform-origin syntax: 3D vs. background-position

From: Alan Gresley <alan@css-class.com>
Date: Sat, 25 Feb 2012 15:36:12 +1100
Message-ID: <4F48653C.7090601@css-class.com>
To: Aryeh Gregor <ayg@aryeh.name>, public-fx@w3.org
On 23/02/2012 3:25 AM, Aryeh Gregor wrote:
> (BCC'd www-style, replies should go to public-fx)
> Bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=15432
> What should something like "transform-origin: left bottom 10px" do?
> According to the old 2D Transforms spec and the current merged spec,
> it places the origin at the left edge of the element's border box,
> 10px from the bottom, with z = 0.  According to the old 3D transforms
> spec, it places the origin at the bottom left of the element's border
> box, with z = 10px.  IE10 Developer Preview, Firefox 13.0a1, and
> Chrome 18 dev all follow the old 3D spec.  Opera Next 12.00 alpha
> (which does not implement 3D transforms) appears to follow neither
> spec, and treats it like "left top" as far as I can see, which I admit
> that I don't understand at all.

A few questions since we do not have depth: <value>; (for z-dimension) 
and we do not have display devices that project cubes.

1. How it is possible to have transform-origin for a z-axis when the 
element in question is 2 dimensional (only x and y axis) box.

2. The bug report has a test with rotate(). This is rotateZ() in 3D 
virtual space. Why would you not use translateZ().

3. The bug report shows that Dean has proposed transform-origin-z. How 
would transform-origin-z and translateZ() behave differently.

(Aside, I do believe background-position was poorly designed)

Alan Gresley
Received on Saturday, 25 February 2012 04:36:42 UTC

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