W3C home > Mailing lists > Public > public-respimg@w3.org > March 2015

Re: Picture Element Explanation.

From: Paul Deschamps <pdescham49@gmail.com>
Date: Thu, 5 Mar 2015 09:56:22 -0500
Message-ID: <CACPLTHh7xrv1gr2GohMT0iZX1M61v_vK_8bk8hhmycXc1wNQRg@mail.gmail.com>
To: Jason Grigsby <jason@cloudfour.com>
Cc: "public-respimg@w3.org" <public-respimg@w3.org>
Thanks Jason.

What I am looking for here is a sound code example that compare's and
contrast's the two methods. However I do appreciate your reply! That was if
you recall my initial request.

If performance is the main concern in lieu of breaking the separation of
presentation from content then let's look at that. What are the measurable
gains here? Show me the code.

If it comes down to the double download issue Chrome currently supports a
CSS only solution replacing the IMG src so the Double download doesn't
exist there. Would it not be better to focus on that kind of a solution for
the other browsers? Clearly someone else is in agreement with me here as
it's already supported in Chrome.

- No SRC specified Chrome responsive technique negates the double download
http://jsfiddle.net/n935nznp/3/

- The same code showing the double download issue
http://jsfiddle.net/mv3squpn/1/

I've read the use cases some time ago; I can see very little here that is
already not supported in a css media-query solution. The "only" argument
for the picture element I can see is for this double download.

Cheers!

Paul.


On Thu, Mar 5, 2015 at 9:38 AM, Jason Grigsby <jason@cloudfour.com> wrote:

> 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.
>> >>
>> >
>>
>>
>
>
> --
> +1 (503) 290-1090 o | +1 (503) 502-7211 m | http://cloudfour.com
>
Received on Thursday, 5 March 2015 14:56:50 UTC

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