RE: Picture Element Explanation.

Hi Paul,

I think it’s important to call out that you can address your concerns with Javascript & CSS, but as Jason calls out, this standard was conceived due to the limitations inherit in the technology.

Welcome to the web. That isn’t meant to be snarky, but in that web technologies provide the scaffolding which doesn’t address every use case we throw at it. When you meet that limitation, you have other tools at your disposal. I liken this to the dichotomy between CSS and preprocessors - preprocessors add another dimension to CSS that isn’t available in the spec.

If you’re interested in a javascript solution, there are many out there, but based on your dialog BBC News’ Imager might be a good solution:
https://github.com/BBC-News/Imager.js/



Jason Day
User Experience Engineer
jbday@llbean.com<mailto:jbday@llbean.com> | 207.552.7084

L.L.Bean
15 Casco Street | Freeport, Maine 04032

From: Jason Grigsby [mailto:jason@cloudfour.com]
Sent: Thursday, March 05, 2015 9:39 AM
To: Paul Deschamps
Cc: public-respimg@w3.org
Subject: 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<mailto: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<mailto: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<mailto: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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