Horizontal scroll-bars for block math

[TimArborealis]

We discussed the possibility of preventing line breaks in block expressions that overflow the page width. This can be neatly solved by a scroll bar, just like for tables in the new EPUB guidelines. As I understand it, it will only affect the visual display and not tamper with the braille output.

We did some testing at MTM by adding this to the CSS:

math[display~='block'] {
overflow-x: auto;
overflow-y: hidden;
}

Would be great if others could try this out and confirm whether or not it works!

[samimaattaCelia]

I tested and it works with Chrome, but not Firefox. This means that we should really be testing with reading systems and not rely on browsers (as I have done). We do know that Thorium Reader is based on Chromium, so we get some information from using it.

Did you test how the scrolling supports keyboard navigation? This is a problem with tables and they need to be made focusable with tabindex attribute. It might be that <math> elements are focusable by default and it could work as is.

[TimArborealis]

I tested in Thorium with NVDA + MathCAT. The scrollbar did not seem to affect focusability or navigaiton. I suggest we use this, the question is does it belong here or in the CSS guidelines?

[samimaattaCelia]

We should add to the "Inline vs block" section that it is important to use the display attribute to create block expressions and nothing else, so the semantics are correct and the styling works. Maybe we could add that snippet in to highlight it. This could be read by somebody else as well and to them the CSS guidelines might be too much.

I do agree that it is mainly a CSS guidelines thing.

[TimArborealis]

I have made sure that we will include it in MTM:s CSS. I have also talked to Linda and it might make it into the new CSS guidelines. If it doesn't and your CSS differs from ours, I suggest each organisation add this to their CSS if desired.

Handing this issue over to @samimaattaCelia in case he wants to clarify the display situation, otherwise I think we can call it finished.

[MartheGjelstad]

@samimaattaCelia will work on this and close when finished.

[samimaattaCelia]

Closed with previous commit.