Re: Jonathan's concern: Zoom in responsive drops content

Thanks Gregg,

Cutting down to the remaining questions:

Perhaps:
SC X.X.X If text is resized up to 300% without assistive technology, the layout of the Web page ensures that it can be viewed in its entirety without scrolling the viewport horizontally, and without loss of content or functionality except for elements of the page where the spatial layout of the content is essential to its use.


  *   why 300 %
I picked 300% due to the next point, but it is obviously up for discussion.
Oh, I also thought of another example: TV listings. A large set can be a cross between a data-table and a map!


  *   ‘essential to its use’  (essential in who’s opinion?)
Have we not had wording like this before? Something like “would undermine the purpose of the content”.

Doing a (lazy!) search in WCAG “essential” is defined as “if removed, would fundamentally change the information or functionality of the content, and information and functionality cannot be achieved in another way that would conform”.
Used in 1.4.5: “Essential: A particular presentation of text is essential to the information being conveyed.”
(and 2.2.1).
That seems reasonable to me, or have there been problems with that?


Jonathan wrote on the topic of zoom level vs resolution:
…
Gregg:
Oh  — one other thing - “when zoomed”
users often use PINCH ZOOM  and DO NOT WANT it to do anything more than an image zoom.

AC: I agree that sometimes people want to pinch zoom, BUT, I think it is a problem that there is not a way of zooming with re-flow on mobile. It’s a UA issue primarily as there isn’t a mechanism on the dev side to deal with it [1].
Has that been covered elsewhere?

Gregg:
I think there was a post about different types of zoom  (I don’t find it quickly but something like (or better than) the following
·         character zoom n  (enlarging fonts —  and images usually) (with reflow)
·         virtual page width change  (zoom but keep visual page width the same- which means virtual page width changes)
·         pinch zoom  (zoom it but don’t change it)


AC: I would characterize differently, there are three types of zoom in practice, I’m partly inventing names to help differentiate:


1.      Text sizing, where ONLY the text size increases (unless the developer uses particular CSS to size other things according to the user’s text size). This is the old/traditional form that has somewhat fallen out of favour compared to the next one, although still available in some UAs if you know where to look (desktop & mobile).

2.      Pixel sizing, where (on a desktop browser) you ZOOM and everything gets bigger. If there are media queries in the CSS they are used and the content is reflowed (Desktop only).

3.      Layout sizing, where you either pinch zoom or magnify in order to make one part of the layout bigger on screen, at the cost of not seeing other areas (mobile with pinch zoom or with a magnifier on desktop).

Cheers,

-Alastair

3] https://alastairc.ac/2015/10/zoom-for-fixed-and-responsive-sites/