Re: [css4-images] Add format() hints to image()

This is indeed a very good suggestion. Using the same syntax font-face uses has many advantages over the current and the format fragment solution. 
I would love to see this in specification as the current design breaks for examples like jake showed in his message. I would love to be able using image() this way.

-Anselm Hannemann

Am 14.02.2013 um 12:08 schrieb Yoav Weiss <yoav@yoav.ws>:

> +1 for the format() solution, which IMO is the cleanest one, and will be familiar to developers, since they already know it from font-face. 
> Introduction of new formats may require to extend the spec. Since it is not highly frequent, it may not be an issue. Browsers can simply ignore resources with unknown type.
> 
> Looking at the extension is a heuristic solution at best, since extensions are often inaccurate.
> 
> This issue has been bothering me for a while now, making the image format fallback practically unusable. I'd love to see it fixed.
> 
> Yoav
> 
> 
> On Thu, Feb 14, 2013 at 11:40 AM, Jake Archibald <jaffathecake@gmail.com> wrote:
>> The problem: image('whatever.webp', 'whatever.png')
>> 
>> If the browser doesn't support webp it will still download 'whatever.webp' and attempt a decode before it'll fallback to the png. It could exit early when it gets the content-type header, but that's still more network activity than ideal.
>> 
>> Solution: Introduce format(), from @font-face
>> 
>> https://gist.github.com/jakearchibald/2f6baeeefd0eee59d9ec
>> 
>> The browser wouldn't bother with the webp if it doesn't understand it. Like fonts, format isn't limited to mime types, allowing for format('webp-progressive'), if webp ever gets a progressive format.
>> 
>> The formats would be defined by the spec, as with fonts.
>> 
>> Alternative solution: format fragment
>> 
>> https://gist.github.com/jakearchibald/2f6baeeefd0eee59d9ec#file-gistfile1-css-L12
>> 
>> We already use the fragment for media fragments, could use it for format too. However, this creates repetition in image-set. Meh.
>> 
>> Another alternative: Look at the 'extension'
>> 
>> Could look at the suffix of the url. This has repetition in image-set as above, but also feels clunky, especially for format sub-types, eg whatever.webp-progressive.
>