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Re: useful units (ACTION-27)

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Tue, 3 Feb 2009 10:41:49 +1100
Message-ID: <2c0e02830902021541s5e85b1c5i1e4348fc9b1434ca@mail.gmail.com>
To: Yves Lafon <ylafon@w3.org>
Cc: public-media-fragment@w3.org

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.

Cheers,
Silvia.

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
>
>
>
Received on Monday, 2 February 2009 23:42:26 GMT

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