[whatwg] Responsive images and printing/zooming

[Tab Atkins Jr.]

On Wed, May 16, 2012 at 6:15 AM, Markus Ernst <derernst at gmx.ch> wrote:
> I read the current spec and huge parts of today's discussions to find out
> how images with multiple sources are intended to behave when printed, or
> when the page is zoomed, but I found no hints. I think some words on this
> might be useful in the spec, regardless of what the final syntax will be.
>
> 1. Print
> When a page is printed (or also converted to PDF or whatever), both
> "viewport" width and pixel ratio change. Are UAs expected to load the
> appropriate sources then? This could result in increased bandwidth, delayed
> printing, and IMHO a disturbed user experience, as the image may differ from
> the one seen on screen. Thus, I suggest to always use the resource actually
> shown on screen for printing.
>
> 2. Zoom
> On mobile devices, web pages are often zoomed out to fit the viewport width
> by default, the user is supposed to manually zoom in and scroll in order to
> read parts of pages. I understand that the whole thing about responsive
> design is to make this kind of zooming unnecessary, but in practice there
> will be all kinds of partly responsive designs using responsive images.
> Specially in cases where separate sources are given to match device pixel
> densities, zooming might matter, as for a zoomed-out page the low res image
> might be more than sufficient, but after zooming in the higher resolution
> might be appropriate. Which OTOH can disturb the user experience, when the
> images differ.

I'm with Odin.  Both of these seem like simple
quality-of-implementation issues.  We shouldn't overly restrict
browsers right now, so we can see what works best in the wild.  If
necessary, we can come back through later and tighten the
restrictions.

~TJ