On 11/6/13, 3:24 PM, Yoav Weiss wrote:
On Wed, Nov 6, 2013 at 11:33 PM, Benjamin Poulain <benja...@webkit.org <mailto:benja...@webkit.org>> wrote: On 11/6/13, 10:53 AM, John Mellor wrote: On Sun, Oct 20, 2013 at 2:00 AM, Maciej Stachowiak <m...@apple.com <mailto:m...@apple.com> <mailto:m...@apple.com <mailto:m...@apple.com>>> wrote: > > My initial impression is that it seems a bit overengineered. I sympathize. The issue of srcN appearing to be a complex solution to a seemingly simple problem came up again on IRC chatting to rniwa, so I thought I'd try to explain this briefly. Unfortunately, responsive images is a deceptively complex problem. There are 3 main use cases: 1. dpr-switching: fixed-width image resolution based on devicePixelRatio. 2. viewport-switching: flexible-width image resolution based on viewport width and devicePixelRatio. 3. art direction: same as #1 or #2, except additionally, must serve completely different images based on viewport width. How important and common are each of those use cases? Handling every imaginable use case by the Engine is a non-goal. There has been a lot of demand for dpr-switching since the first iPad Retina. This has caused some very ugly hacks on the Web. It is very important to address that issue. Viewport switching is usually done to adapt images for mobile device VS large/huge display devices. It is a valid concern but it is not easily addressed. Srcset can/should likely be improved regarding this. I believe (feel free to prove me wrong) dynamic viewport adaptation and what you call "art direction" is not as common. On a survey ran at the last Mobilism conference (and on Twitter) 41% of respondents said they're already using some hack to get their responsive image "art-directed". A manual responsive site survey <http://japborst.net/blog/the-current-state-of-art-direction.html> showed that 23% of the sites "art-direct" their images, and 58% do that when (subjectively) the design requires it. So it might not be as common as viewport switching (which is practically everywhere), but it is pretty common.
The survey you linked (http://japborst.net/blog/the-current-state-of-art-direction.html) was targeting specifically responsive websites. Those websites represents only an unquantified subset of the web.
Even with that very targeted subset, only a small percentage was actually implementing art-direction.
It looks to me like art-direction should not be imposing all the design constraints over the more important use cases.
Something that is still unclear to me is why srcN would be doing a better job than JavaScript for art-direction? There are many complex cases that are handled dynamically (changing images on zoom; tiling large images on zoom; changing layout on rotation; creating popover style layout when switching portrait/landscape, etc).
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