Section 508 accessibility issue with underlying Canvas element with no name.

[rgutierrezatx]

Configuration:

• Chrome Version 96.0.4664.110 (Official Build) (64-bit)
• Windows 10
• PDF.js version: linked to official demo of pdf viewer
• Is a browser extension: no

Steps to reproduce the problem:

1. Go to official mozilla pdf viewer demo at https://mozilla.github.io/pdf.js/web/viewer.html
2. run ANDI ( https://www.ssa.gov/accessibility/andi/help/install.html )

What is the expected behavior? the underlying Canvas should have an accessible name

What went wrong? see screenshot for the error. A name should be set or at least allow us to set this name

[Snuffleupagus]

@brendandahl Is this somewhat expected after PR #13118 (which removed the "aria-label" on the canvas-elements), or is that not entirely relevant here?

[rgutierrezatx]

@Snuffleupagus appreciate the quick response to this issue. We are hoping for a quick turn-around since this one minor issue puts the whole thing out of compliance for Section 508 accessibility.

[marco-c]

@MReschenberg is this something you could help us with? In #13118 we removed the aria-label from the canvas as it was not needed anymore (see discussion at #13118 (comment) for the reason).
Is there any way to tell that the element doesn't need an aria-label or something like that?

[marco-c]

Maybe we can set "aria-labelledby" on the canvas to point to the div that contains it?

[Snuffleupagus]

Maybe we can set "aria-labelledby" on the canvas to point to the div that contains it?

That would likely be problematical, since I'm assuming that it'd require adding unique ids to the pages in the viewer; please refer to issue #11499 and PR #11503 for context.

[MReschenberg]

@MReschenberg is this something you could help us with? In #13118 we removed the aria-label from the canvas as it was not needed anymore (see discussion at #13118 (comment) for the reason). Is there any way to tell that the element doesn't need an aria-label or something like that?

What's the semantic use of the <canvas> element inside of the region? It looks like we're using the <region> to define the page area, and the canvas to draw the page background. If the <canvas> is purely presentational, it should have role=presentation, which will also make it so it no longer requires a label attribute.

[rgutierrezatx]

has the viewer at https://mozilla.github.io/pdf.js/web/viewer.html been updated with this change? i still get the same accessibility name issue.

[marco-c]

@MReschenberg it looks like this ANDI tool from the US government considers the <canvas role="presentation"> element as problematic because it doesn't have an accessible name:

[marco-c]

I wonder if this isn't a bug in the ANDI tool...

[marco-c]

Yes, I think so, I even tried with an empty page with just the canvas and role presentation and ANDI is still complaining. Probably it isn't taking into account the role.

@rgutierrezatx do you have a way to report this problem to the ANDI developers?

[marco-c]

I filed SSAgov/ANDI#138 on the ANDI GitHub repo.

[rgutierrezatx]

I filed SSAgov/ANDI#138 on the ANDI GitHub repo.

ANDI resolved the issue in their tooling and closed your ticket. thanks!