W3C home > Mailing lists > Public > public-media-fragment@w3.org > February 2009

Re: useful units (ACTION-27)

From: Yves Lafon <ylafon@w3.org>
Date: Tue, 3 Feb 2009 05:09:33 -0500 (EST)
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
cc: public-media-fragment@w3.org
Message-ID: <Pine.LNX.4.64.0902030509040.9729@ubzre.j3.bet>

On Tue, 3 Feb 2009, Silvia Pfeiffer wrote:

> I agree with the use of pixels and cm for spatial fragment specifications.
> Maybe points, too, but I don't really see that as necessary.

Meaning you are against using percentages ?

>
> On Tue, Feb 3, 2009 at 2:40 AM, Yves Lafon <ylafon@w3.org> wrote:
>>
>> During our last f2f, we discussed the applicability of some units and the
>> need to create a list for them.
>> We have two axis, the temporal axis, and the display axis.
>>
>> The temporal axis is currently debated (see the discussions on the list
>> regarding seconds (as real numbers) vs frame-oriented units.
>>
>> For the display axis, we rule out the units relative to the document it
>> would be displayed in (as the server has no way to know the document the
>> unit is relative to). So it leaves us with units relative to the
>> characteristics of the video/image presented:
>>
>> * Pixels
>> * percentages (as percentage of width and height)
>>
>> It would be interesting also to define only one axis (x or y), and define an
>> aspect ratio, like aspect(16:9), in that case the aspect ratio could be an
>> relative unit (relative to the other unit in use).
>>
>> * in, cm when the media gives the information about the relationship
>>  between pixels and in/cm so in general not applicable. Do we want them ?
>>
>> All other units used in CSS (like pt, pc, em) are dependant on the
>> definition of pt, and linked in CSS2 to cm/in (as 1pt = 1/72 in), but a
>> fragment might be applicable to renderer not using this default, so I would
>> avoid those.
>>
>> --
>> Baroula que barouleras, au tiéu toujou t'entourneras.
>>
>>        ~~Yves
>>
>>
>>
>

-- 
Baroula que barouleras, au tiéu toujou t'entourneras.

         ~~Yves
Received on Tuesday, 3 February 2009 10:09:42 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 21 September 2011 12:13:32 GMT