On Sat, May 12, 2012 at 11:17 AM, Maciej Stachowiak <[email protected]> wrote: > > On May 12, 2012, at 6:28 AM, Mathew Marquis <[email protected]> wrote: > >> While that information may be available at the time the img tag is parsed, I >> don’t believe it will be available at the time of prefetching — I’m happy to >> research this further and report back with citations. I’m sure I don’t have >> to tell you that “disable prefetching on img tags just in case there are >> matching sources” is going to be a hard sell to vendors that do prefetch. If >> we’re left with a solution that fetches the original src before applying any >> custom source logic, well, we’re no better off than we would be with one of >> the scores of script-based solutions that have come about in the past year. >> >> To your original point, though: as much as you can absolutely make a case >> that a simpler implementation will benefit developers if inherently more >> stable, you can’t convince me that `img set` suits the needs of developers >> as well as `picture`. In fact, even if you were to convince me, it wouldn’t >> matter. Picture is, for better or worse, what developers want and expect in >> a “responsive images” element. There’s certainly no shortage of proof of >> that, on this page alone: >> http://www.w3.org/community/respimg/2012/05/11/respimg-proposal/ At the >> moment, the Community Group server seems to be down due to excessive traffic. > > The key to making the case for the <picture> element or something like it is > to cite use cases. Most of the comments on that blog post just give opinions, > without use cases backing them up. A lot more weight will be placed on > explanations of *why* developers love something (e.g. it lets them do X where > they otherwise couldn't, it lets them do Y more easily, etc) than just > testimonials that they love it. > > Regards, > Maciej > > > P.S. Your examples in that blog post are not equivalent. Here are two > examples that I believe would be equivalent for resolution adaptation only, > presuming a 600x200 image and a 1200x400 scaled version: > > <img src="catface.jpg" alt="A cat's face" srcset="[email protected] 2x"> > > <picture style="width: 600px; width: 200px" id="catface_picture" alt="A cat's > face"> > <source src="catface.jpg"> > <source src="[email protected]" media="min-device-pixel-ratio: 2"> > <img src="catface.jpg" alt="A cat's face"> > </picture> > > Other than more general verbosity, there are a few other other differences > that show up: > > 1) The <picture> version has to repeat the alt text. > 2) The <picture> version has to repeat the URL to the 1x asset. > 3) The <picture> version has to explicitly set a width and height, because it > does not have the built-in scaling semantics of srcset and so cannot rely on > intrinsic size, since it will end up different between the two images. > 4) The <picture> version has to use a specific order, while in the srcset > version, order doesn't matter.
Does the id="catface_picture" attribute play an essential role in this example, or is it just extra clutter in the <picture> example? Adam
