- From: Boris Zbarsky <bzbarsky@MIT.EDU>
- Date: Thu, 18 Nov 2010 09:58:32 -0500
- To: Chris Marrin <cmarrin@apple.com>
- CC: www-style list <www-style@w3.org>
On 11/18/10 9:50 AM, Chris Marrin wrote: > I agree that the matrix() should be unitless, and not because of its mathematical "correctness". I just think it is confusing to authors to require units in 2 parameters and not the others. But it's not confusing that some of the entries act like pixel lengths while others do not, even though they all don't have units? > Think about matrix() for 3D transforms. There you pass 16 numbers. Parameters m41, m42 and m43 typically represent the translation of the coordinates. Should those 3 parameters be required to have units, but the other 13 are required to have no units? Imo, yes. > That's very confusing. It's only confusing if you have a particular mental model involving projective coordinates in mind. Of course matrix() as a whole is probably pretty darned confusing for authors, complete with its "weird" element ordering, etc. > If you're using matrix() you're doing some (possibly very complex) math, so you should provide no units. How does that follow? If _I_'m using matrix() in a web page, I'm probably doing math in support of some physics, personally, and I better be using correct units everywhere to stay sane instead of having units magically implied somewhere! -Boris
Received on Thursday, 18 November 2010 14:59:09 UTC