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Re: 200% website scaling


From: Patrick H. Lauke
Date: Nov 28, 2019 12:45PM

On 28/11/2019 18:55, glen walker wrote:
> In Windows 10, the "Make everything bigger" option (scaling) is in the
> "Ease of Access" settings, which can be considered an accessibility
> feature. 1.4.4 says "...text can be resized *without assistive technology *up
> to 200 percent...".

Not really. It's a display setting, not an accessibility setting.

Changing the system's scaling will, in essence, change the number of
logical/CSS pixels used. It changes the relationship between the
hardware pixels on the display, and the logical/display pixels used.

So what is happening here is that when you have a higher scaling than
100%, you're essentially making the viewport in the browser smaller.
i.e. the same problems would appear if you ran your browser window not
full-screen/maximised, but at a smaller windowed size.

Resize text in theory applies to any possible viewport size. At any
possible viewport size, a user should be able to resize text up to 200%
without adverse effects (things being cut off, overlapping ... but note
that scrollbars are fine, they're not prohibited by 1.4.4).

Long story short: if you're having situations in which 200% zoom in
browser does lead to unusable content (in terms of content being cut off
and unreachable, even with scrolling, over overlapping), then yes that's
a failure of 1.4.4.

> So if your page looks good at 200% zoom in browser and windows scaling is
> 100% (essentially assistive technology is turned off), then I'd say you're
> ok. If you change your scaling (turning assistive technology on), then
> while it would be nice to support browser zoom, if it doesn't completely
> work, it's not necessarily a 1.4.4 failure.
> It might depend what you mean by "not usable". If your page does not
> reflow properly, the problem might be reproducible without scaling turned
> on, in which case it would be a 1.4.4 problem.

Let's not confuse the matter by talking about reflow, which has nothing
to do with 1.4.4. That's a 1.4.10 thing. And yes, there, content should
adapt/reflow to the viewport correctly and not cause two-directional

Patrick H. Lauke

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