Re: Horizontal scrolling & reflow

Hi David,

(Chair hat off btw, I intended to bring this to the group to check my (and everyone’s) understanding of this niche scenario.)

> I don't remember discussion distinguishing content from a web page for the purposes of this SC.

It was part of the internationalisation discussion, there’s a thread here:
https://github.com/w3c/wcag21/issues/674



> I think the intention is that western users should not have to horizontal scroll and Eastern LV users shouldn't have to vertically scroll.

The problem is that within “eastern” pages there are likely to be both vertically and horizontally read / scrolled content. An example from that thread: http://tategaki.github.io/awards/  (I’m not saying that meets the SC, just that it demos multiple content directions. And: Vestibular trigger warning!) Or a complete page: https://www.chenhuijing.com/zh-type/


Both CSS Grid and Flexbox layout methods have been designed to be reading-mode independent, i.e. work left-right and/or top-bottom. You can literally change a value or two and the whole layout switches direction!
So the support is improving rapidly, and we were considering reading-mode during the SC development.


> It is vertically scrolling page (Western languages) and adding horizontal for one paragraph would be 2 directions of scrolling so the only exception I can see in the SC is "Except for parts of the content which require two-dimensional layout for usage or meaning."

The same SC is covering a lot of scenarios, the main four we’re thinking about here are:

  1.  Vertically scrolling pages which require horizontal scrolling (unnecessarily)
  2.  Horizontally scrolling pages which require vertical scrolling (unnecessarily)
  3.  Vertically scrolling pages with sections of horizontal scrolling (necessarily for some languages)
  4.  Vertically scrolling pages with sections of horizontal scrolling (for some interactive elements)

So like a fishing net with particular shaped holes, we want to catch certain things but not others. We want to catch 1 & 2, not catch 3, and I think it is ok not to catch 4 if it fits the SC text. But that’s what I’m checking with the group: scenario 4.

From a LV point of view, multi-direction scrolling can be confusing. Heck, it can be for anyone, but clear design & scroll bars can help with that. Where it is most problematic is where you cannot fit the entire element (block of text or otherwise) into the viewport as you scroll.

I.e. A horizontally scrolling block of text or set of images is ok if it fits in the viewport as you scroll horizontally.

So what I’m saying is: If you have a section of a vertically scrolling page that scrolls horizontally, it is ok if it fits with 256px high.

I don’t think that will affect blocks of text very much, because in a 320 x 256px view you can’t fit large blocks of text, the wrapping would go out of that area.

What I’d like to avoid is banning (small) interactive elements that, as part of their interaction, use horizontal scrolling.
E.g. one of the methods for having a toolbar that fits in a small view is to allow horizontal scrolling!

It would be counter-productive to prevent techniques which help make zoomed-usage work.

Cheers,

-Alastair