Combine sizing SCs

[alastc]

Hi,

This is sort of a meta-topic, but I'd like to suggest combing the text & overall content sizing SCs, or at least replacing the content-sizing one.

Issues with Text sizing

Increasing the size of text without re-flowing the page layout leads to broken layouts at 150%, let alone 300% or 500%. There are techniques for triggering re-flow when text-size is increased (i.e. basing your media queries on EM units), however, if you take that approach it is exactly equivalent to using pixels and zoom. See the Guardian website for an example.

The SC has to apply to every website, and for news sites, applications, dashboards, this is not a workable thing. (It isn't just me saying this, other accessibility advocates have come to very similar conclusions.)

Also, how do you test whether a website passes this? You would have to know which user-agent had the highest level of text-sizing and use that. That is not a workable solution, there needs to be a figure that we cap as maximum that can be tested across.

Issues with size all content

The proposed SC text is "Users can change the size of all content", but in that sense it could be fulfilled by any site, it doesn't say how much. I can re-size the content of any size 10%, but I don't think that is the intent.

The description talks about zoom preserving spacial relationships, which it can do only at the expense of horizontal scrolling (which we want to avoid).

The testing talks about zooming to the user-agent maximum, and we run into the problem for testing of "which user agent?".

Proposal

I don't have access to editing the LVTF area of the wiki, but there is a proposed equivalent David and I worked on which gets around these issues:
https://www.w3.org/WAI/GL/wiki/Possible_wording_from_Jason/David_for_LVTF_re:_zoom_without_horizontal_scroll

SC X.X.X The content of the Web page can be increased to 300% without loss of content or functionality, without bi-directional2 scrolling, with following the exceptions:

• If the spatial layout of some the content is essential to some of the content's use, that part of the content is exempt.
• If the user-agent fits the layout to the viewport and does not provide a means of reflowing content, bidirectional scrolling is exempt.

That accounts for:

• Testing, there is a standard people can test to.
• User-agents which do not allow for re-flowing layout (mobile devices).
• Content which can't be re-flowed.

The 300% figure is achievable today. Most website which are responsive will re-size up to 300% quite easily on desktop due to working on mobiles. 400% is probably achievable, but I think we'd need to show that it can work across different types of website.

I'm sure there are improvements, the first thing might be a fall-back SC for text-only increases if a site is not responsive, but it would have to be more limited than the current proposal, say 200% to match current WCAG. More than that wouldn't work across the majority of websites & devices.

[DavidMacDonald]

The original wiki workup for this is here.
https://www.w3.org/WAI/GL/wiki/Possible_wording_from_Jason/David_for_LVTF_re:_zoom_without_horizontal_scroll

[joshueoconnor]

Like it.