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Re: [css3-images] Image fallback feature's dependency on media fragments

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 15 Feb 2012 16:27:01 -0800
Message-ID: <CAAWBYDByu30+HY=c36RtOWA+dM4EQ9AGKeERz77bZOfdPywd1g@mail.gmail.com>
To: "Kang-Hao (Kenny) Lu" <kennyluck@csail.mit.edu>
Cc: WWW Style <www-style@w3.org>
On Wed, Feb 8, 2012 at 9:15 AM, Kang-Hao (Kenny) Lu
<kennyluck@csail.mit.edu> wrote:
> 3.2. Image Fallbacks and Annotations: the ‘image()’ notation
>
>  # So that authors can take advantage of CSS's forwards-compatible parsing
>  # rules to provide a fallback for image slices, implementations that
>  # support the ‘image()’ notation must support the xywh=#,#,#,# form of
>  # media fragment identifiers for images. [MEDIA-FRAGS]
>
> Is this what implementers are planning to do? It it is, there's nothing
> I would complain. If it is not, as the feature of media fragments seems
> to be heavier than than feature of image fallback, it seems enough here
> if we only require "implementations that support the 'image()' notation
> but not xywh=#,#,#,# must treat such URL as a 404 image" so Example 4:
>
>  # background-image: url('swirl.png'); /* old UAs */
>  # background-image: image('sprites.png#xywh=10,30,60,20'); /* new UAs */
>
> can be written as
>
>  | background-image: url('swirl.png'); /* old UAs */
>  | background-image: image('sprites.png#xywh=10,30,60,20', 'swirl.png');
>  | /* new UAs that support fallback image. Might or might not support
> media fragment */
>
> What are implementers' plans here?

I don't know about impl plans, but if they aren't planning to support
media fragments in the very near future (in the next 3-4 months, I'd
say), then I like your suggestion to at least force browsers to
*recognize* media fragment URLs and explicitly fail to understand
them.  That's the whole reason for the requirement, after all.

~TJ
Received on Thursday, 16 February 2012 00:27:48 GMT

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