726583 - Support extra two arguments for rotate() in 'transform' property

Status: RESOLVED WONTFIX

(Core :: CSS Parsing and Computation, enhancement)

Description

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

The current specification defines rotate() as follows:

"""
rotate(<angle>[, <translation-value>, <translation-value>])
specifies a 2D rotation by the angle specified in the parameter about the origin of the element, as defined by the transform-origin property, or a given point as to the origin of the element. For example, rotate(90deg) would cause elements to appear rotated one-quarter of a turn in the clockwise direction. With rotate(90deg, 100px, 100px) the element appears rotated after a translation of 100px in the vertical and horizontal direction. The actual origin of the element is not affected.
"""
http://dev.w3.org/csswg/css3-transforms/#two-d-transform-functions

This matches SVG Transforms, but doesn't match any implementation of CSS Transforms.  Dirk Schulze recently added the extra two arguments to the spec to better align CSS Transforms with SVG Transforms:

https://www.w3.org/Bugs/Public/show_bug.cgi?id=15508

Does Gecko want to implement the extra arguments?  I personally don't see the need, but maybe I'm undervaluing alignment with SVG . . .

Comment 1

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Dirk wrote a fairly long www-style post arguing that this change would make unification of SVG and CSS transforms easier to implement, because of interactions with the SVG DOM:

http://lists.w3.org/Archives/Public/www-style/2012Feb/0521.html

I admit that I'm not familiar with the SVG features he's talking about, so I'm not qualified to judge his arguments.  From the perspective of someone writing CSS by hand and not SVG, which I think is the large majority of authors, it seems like a small but definite loss.

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

I think these extra arguments should not be added to the spec and we should not implement them.  I'm not sure why the editor unilaterally added them.

Comment 3

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

These were removed from the spec.