W3C home > Mailing lists > Public > www-svg@w3.org > January 2006

Re: Is the px unit equivalent to user units?

From: Dean Jackson <dino@w3.org>
Date: Wed, 4 Jan 2006 06:54:12 +1100
Message-Id: <99CCC18C-149D-4729-8FAB-8D95FD534D8F@w3.org>
Cc: Jon Ferraiolo <jonf@adobe.com>, Doug Schepers <doug@schepers.cc>, Jonathan Watt <jonathan.watt@strath.ac.uk>, www-svg@w3.org
To: Ian Hickson <ian@hixie.ch>


On 04/01/2006, at 5:00 AM, Ian Hickson wrote:

>
> On Tue, 3 Jan 2006, Jon Ferraiolo wrote:
>>
>> I think nearly all of the long-standing members of the SVG WG would
>> agree that it would be preferable to drop CSS units from all  
>> version of
>> the SVG language (except for defining the intrinsic size of the  
>> graphic
>> via width/height on the root svg element) rather than require an
>> abomination such as requiring 'uu' or 'csu' on SVG length values just
>> because CSS purists have a religious issue about unitless values.
>
> I really don't understand the problem. This has nothing to do with
> religion, it's to do with real problems with syntax (e.g. line-height
> handles <number> and <length> very differently).
>
> We have many times suggested a simple solution:
>
>  * Continue to have the "px" unit in text/css be exactly equivalent to
>    unit-free "user units" in SVG.
>
>  * If other units are used, convert them to "px" units (and thus user
>    units) in exactly the same way that CSS already requires.
>
> This is what the specs *already say*. This is scalable. It is  
> completely
> compatible with all existing specs and content.

I agree with this solution. (I actually thought we'd already decided to)

Dean

>
> Then:
>
>  * Remove the requirement that SVG places on CSS parsers to accept
>    <length>s that are just <number>s.
>
> This resolves the one issue that keeps being raised. SVG Tiny 1.2  
> already
> does this (in fact it removes all requirements on CSS parsers).
>
> -- 
> Ian Hickson               U+1047E                ) 
> \._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _ 
> \  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'-- 
> (,_..'`-.;.'
Received on Tuesday, 3 January 2006 19:54:39 GMT

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