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Re: [css3-images] Features Overview

From: Raphaël Troncy <raphael.troncy@eurecom.fr>
Date: Wed, 06 Jul 2011 12:07:10 +0200
Message-ID: <4E1433CE.5080801@eurecom.fr>
To: fantasai <fantasai.lists@inkedblade.net>
CC: www-style@w3.org, public-media-fragment@w3.org
Dear fantasai,

> Something like:
> | For images containing multiple sizes, if a fragment identifier using
> pixel
> | coordinates, is first resolved into percentages using [some heuristic].
>
> The heuristic in CSS3 Images for picking the right variant image is:
>
> # If an object (such as an icon) has multiple sizes, then the largest size
> # is used.
> # If it has multiple aspect ratios of that size (or of no size), then the
> # aspect ratio closest to the aspect ratio of the default object size is
> used.
> # http://dev.w3.org/csswg/css3-images/#default-object-size
>
> The latter sentence is pretty arbitrary. You can pick a different
> arbitrary,
> e.g. the ratio closest to a square is chosen, and portrait is preferred
> over
> landscape. Or vice-versa.
>
> The issue here is that CSS should, ideally, choose the variant that gives
> the best resolution for the shape we're trying to squeeze the image into.
> So we need the multiple sizes available, but they all have to represent
> the same part of the image in the normal case (an icon image, of consistent
> aspect ratio, with multiple resolutions packaged together).

I follow up this discussion thread. This issue has also been discussed 
during the last Hypertext Coordination Group telecon [1]. Following 
these discussions, we have added the following sentence to the spec:

"Note that in the case of pixel-based clipping areas, application of 
those areas to multi-resolutions visual media is undefined."

in the section 4.2.2 [2].
I think that the CSS WG is also discussing the Media Fragments spec in 
today's call. Could you please let us know if this spec edit address 
your comment?
Best regards.

   Raphaël

[1] http://www.w3.org/2011/07/01-hcg-minutes.html
[2] 
http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#naming-space

-- 
Raphaël Troncy
EURECOM, Multimedia Communications Department
2229, route des Crêtes, 06560 Sophia Antipolis, France.
e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
Tel: +33 (0)4 - 9300 8242
Fax: +33 (0)4 - 9000 8200
Web: http://www.eurecom.fr/~troncy/
Received on Wednesday, 6 July 2011 10:08:22 GMT

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