[whatwg] Features for responsive Web design

Matthew Wilcox mail at matthewwilcox.com
Wed May 16 12:14:04 PDT 2012

On 16 May 2012 20:04, Tab Atkins Jr. <jackalmage at gmail.com> wrote:
> On Wed, May 16, 2012 at 11:55 AM, Matthew Wilcox <mail at matthewwilcox.com> wrote:
>> On 16 May 2012 19:47, Tab Atkins Jr. <jackalmage at gmail.com> wrote:
>>> On Wed, May 16, 2012 at 5:58 AM, Matthew Wilcox <mail at matthewwilcox.com> wrote:
>>>> Also, srcset does not abstract the control points away from the image
>>>> itself. I have already been over why this is a problem and
>>>> future-unfriendly. Breakpoints are based on a when a *design* becomes
>>>> visually broken, not on the width of a device. So, when a design
>>>> changes, so will the response breakpoints, and that would mean having
>>>> to revisit and edit every image that's had srcset applied - unless I
>>>> am missing something (which given the last day or two, I may well be).
>>> You're right that changing your breakpoints requires changing all the
>>> @srcset declarations.  An unfortunate aspect of our inability to
>>> abstract away some of the functionality without breaking some of the
>>> features (like being preloader-friendly).
>> I must admit, I am still confused about the pre-loader issue. I'm not
>> sure whether the plan is that we'd be able to convince vendors to
>> disable it on <img/> elements containing srcset (or whatever solution
>> ends up final) or whether this is something that has to be worked with
>> now (in which case the <meta> variable idea seems to me the only one
>> that could work).
> Given the current syntax, the idea is that browsers will be able to
> preload the *correct* image from @srcset.  They have all the
> information necessary to make the decision at parse-time.
> I'm not entirely sure how accurate this is, though.  Some better info
> one way or another would be useful.

Cool. That makes sense but would require the browser to update it's
pre-parser behaviour I imagine (i.e., scan the whole element rather
than just try as soon as the src has been read - so it's not backward
compatible right now) :)

>>> However, something similar to your idea certainly seems possible to
>>> use in an extention of the syntax.  Rather than specifying a w/h
>>> component, give a 'case' component that refers to a breakpoint defined
>>> elsewhere.  This could even potentially extend into url-templating.
>> That's the conclusion that was come to at the RICG too, and why
>> http://www.w3.org/community/respimg/2012/05/13/an-alternative-proposition-to-and-srcset-with-wider-scope/
>> was put forward. I haven't received promising feedback from the WHATWG
>> about it though :s
> Yeah, I was purposely calling back to the post you linked above.
> I gave it some criticism here in WHATWG.

Ah, I thought you were. I'll go have another look because I think I
missed it - I'm only aware of one person feeding back - but then it's
the end of the day and I'm not wholey convinced I won't see your reply
and then remember reading it. It's been a busy day. Cheers Tab.

> ~TJ

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