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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.


[1] http://www.w3.org/2011/07/01-hcg-minutes.html

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 UTC

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