Re: Picture Element Explanation.

HI Paul,

Both Yoav and Bruce answered your main question well. The preloader
downloads images long before css and js are ready. Bruce's article is
excellent.

To your point of separation of presentation from content, I don't think
there is a single person in this group who doesn't share your concern.

The constraints of the preloader, the use cases that responsive images need
to support[1], and the fact that images on the web are fundamentally more
complex than they seem at first glance led us to the current standard.

The standard wasn't created haphazardly. It took nearly four years to come
up with a solution that people could agree on given the constraints we're
working with.

As with anything in life, it is possible we missed some amazing solution.
I'm not saying it is perfect. I would never claim that.

But what I am saying is that other possible solutions need to address the
full set of constraints and use cases. So if you're interested in working
on that, I recommend starting with reading up on the use cases and learning
about how the preloader works and why it is important[2].

In the meantime, responsive images is part of the living HTML standard. It
has shipped in Chrome and Opera. It will land in Firefox 38. We've been
working on this for a long time, and we're excited to finally get
responsive image solutions, imperfect as they are, in the hands of
designers and developers who have been clamoring for them.

-Jason


[1] http://usecases.responsiveimages.org
[2]
http://andydavies.me/blog/2013/10/22/how-the-browser-pre-loader-makes-pages-load-faster/

On Thu, Mar 5, 2015 at 5:16 AM, Bruce Lawson <brucel@opera.com> wrote:

> It's probably illegal to self-link, but I get asked similar questions
> a lot at conferences, so wrote up "Why we can’t do real responsive
> images with CSS or JavaScript"
>
> http://www.brucelawson.co.uk/2015/why-we-cant-do-real-responsive-images-with-css-or-javascript/
>
> bruce
>
> On 5 March 2015 at 12:39, Yoav Weiss <yoav@yoav.ws> wrote:
> > The problems with a CSS based solution such as this are:
> > * It incurs a non-trivial performance regression, since the browser now
> has
> > to wait for all CSS to come in and for layout (or style calc at the very
> > least) to take place before it can start downloading the required images.
> > * You leave the browser zero wiggling room for further optimizations in
> > "resolution switching" case, in case the user prefers smaller images, is
> on
> > a bas connection, etc.
> > * You cannot have a reasonable fallback here without incurring a double
> > download in *supporting* browsers, from now on, forever and ever.
> >
> >
> > On Mon, Mar 2, 2015 at 5:34 PM, Paul Deschamps <pdescham49@gmail.com>
> wrote:
> >>
> >> Hi all I hope this message finds you well :)
> >>
> >> I have some questions / concerns about this picture element; I imagine
> >> that this is not the first time someone has called out this proposed
> >> implementation.
> >>
> >> Some background on myself (though I don't generally like to call out my
> >> area's of expertise) however as this is my introductory email to the
> list
> >> perhaps this is a case where it is valid to do so.
> >>
> >> I've been developing in the web for some twenty plus years now; building
> >> everything from small static sites for private business to large scale
> CMS /
> >> GIS web applications since NCSA Mosaic was released.
> >>
> >> I've watched HTML transform from the old days of blink tags and lovely
> >> "site hit counters" to Tables for layout and all the other lovely
> mistakes
> >> that were made back then including of course the "browser wars" when I
> ran a
> >> small business
> >> built on a custom built CMS that pre-dates  Wordpress or even PHP Nuke.
> >>
> >> I've built 20-30 or so GIS cross browser web applications during these
> >> "Browser wars" where IE 6 was the vain of my existence.
> >>
> >> Beyond being a web developer my vocational training is actually in
> Graphic
> >> Design - of which I've been working in photoshop / Illustrator since
> it's
> >> inception. IMHO CSS and the power of it was revealed to me with sites
> like :
> >> http://www.csszengarden.com/ in 2003 and it was sites like these that
> caused
> >> a revolution for the web.
> >>
> >> ...
> >>
> >> But that's enough about myself. :)
> >>
> >> My question is as follows:
> >>
> >> I am a purist and strongly feel that any "Styling / Cosmetic" decisions
> >> should reside within the CSS alone and HTML should only be the
> "construct"
> >> containing structure only. The picture element feels like it's trying to
> >> accomplish
> >> something in the wrong place.
> >>
> >> Would it not be a cleaner solution to simply have cross browser support
> >> for "content: url()" instead? or perhaps there is something that I am
> >> missing here I would love for someone to explain to me why this
> approach is
> >> better than a CSS solution.
> >> and please not dismiss it with a simple phrase.. show me your code.
> >>
> >> Perhaps it is too late but I fear that the advent of this picture
> element
> >> will be looked at in the future just as like "Tables for layout" did in
> the
> >> past.
> >>
> >> Your comments are encouraged and greatly welcomed.
> >>
> >> My fiddle is here: http://jsfiddle.net/n935nznp and supported in
> chrome.
> >>
> >> Cheers and all the best.
> >>
> >> Paul Deschamps.
> >>
> >
>
>


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