Re: [css3-2d-transforms] Interop: matrix() values e,f <number> or <length>

On 11/21/10 3:44 PM, Aryeh Gregor wrote:
> On Fri, Nov 19, 2010 at 3:01 PM, Boris Zbarsky<bzbarsky@mit.edu>  wrote:
>> On 11/19/10 1:26 PM, Chris Marrin wrote:
>>> This brings up a glaring problem with CSSMatrix. When you construct one,
>>> it is not associated with any element, so you can't use an element's style
>>> to convert units. Today, when we encounter the above CSSMatrix constructor I
>>> believe we just convert 50% to a value of 50 or something equally arbitrary.
>>> We should probably amend CSSMatrix to allow an element to be passed to the
>>> constructor. This brings up the next sticky issue of what happens when, for
>>> instance, the client size of the element changes. Do values in the CSSMatrix
>>> change? Madness!
>>
>> Agreed.  Why are we allowing percentages here again?  ;)
>
> Doesn't em cause the same problem?

Em is not as bad as percentages, since it's only affected by computed 
font style, not geometry.  But yes, rereading the original mail "50%" 
was a bad example, since there are lots of other things that are also 
not resolvable without an element (em, ex, rem, rex, at the very least).

-Boris

Received on Sunday, 21 November 2010 20:51:52 UTC