Firefox A11y Audit with inline SVGs - content with images must be labeled - html

Question

If I have the following SVG image for example:
<svg role="img" viewbox="0 0 100 50" height="100px">
<title>Site Logo</title>
<rect x="0" y="00" width="100" height="10" fill="red"></rect>
<rect x="0" y="10" width="100" height="10" fill="salmon"></rect>
<rect x="0" y="20" width="100" height="10" fill="pink"></rect>
<rect x="0" y="30" width="100" height="10" fill="aqua"></rect>
<rect x="0" y="40" width="100" height="10" fill="blue"></rect>
</svg>
I should be hitting a11y svg guidelines by setting role=img and including a <title> element
However, when I run the Accessibility Audit in Firefox, it adds a warning for every element/graphic inside the SVG (path, rect, circ) with the following warning:
Content with images must be labeled. Learn more
But surely I don't need to mark up every individual path within the svg?
What should I do to improve a11y or indicate to FF what the correct alt text is?
Here's a demo page in fiddle that will reproduce this issue

Answer 1

I found that including a <title>Image title</title> tag within the <svg role="img"></svg> tags led FireFox to stop showing the error. Note the inclusion of the role attribute on the svg tag (as noted in an earlier comment), along with any other attributes you may need for the opening tag.
According to MDN Web Docs:
The element provides an accessible, short-text description of
any SVG container element or graphics element.
So, like an alt tag for an <img> element. It sounds like a <desc> tag could be used for additional descriptive information.

Answer 2

I am pretty sure this is a bug, or design flaw in FF's accessibility tool. I have reported it here.
Remember that automated accessibility audits can not catch every issue, and often report false positives. Try installing (e.g.) the WAVE accessibility add-on, which is another automatic accessibility auditor. It makes no such complaint.
w3 says
An img represents a single graphic within a document, whether or not
it is formed by a collection of drawing objects.
So you are right that role="img" on the SVG root should do The Right Thing. The accessibility API will not try to expose the children, but Firefox's current beta version of the accessibility tool obviously does.
I tried your code (wrapped in a bare bones HTML doc) with a screen reader (NVDA) and it didn't try to announce the rects, which is what I would expect. It did announce the accessible name. Actually it announces it twice (which is a known NVDA bug at time of writing).
I also tried putting a <g role="presentation"> element around the contents of the svg, but the accessibility tool still flagged warnings on all the children. This shouldn't be necessary.
So, I think you're good.

Answer 3

Elements with img role have the children presentational property set to true. So rect elements can't have an alternative name.
It's likely due to a bug in this Firefox plugin.
Note that (curiously?) the Accessible Name and Description guidelines state that the name can be:
generated from [...] a host language labeling mechanism, such as the alt or title attribute in HTML, or the desc element in SVG.
So according to this statement you should use the desc element. I'm not sure if it's an error in the documentation as the title element seems to be a more suitable choice.

Answer 4

This might come in late, but it helps all the time.
Since the svg does not have text, including aria-label="descriptive text here" and alt="svg description here" should help with the text label checks.
However, if the svg is just for presentational purpose, using empty alt helps out as well. This is to make screen readers recognise the svg, but will not describe the image (instead they'd just say "image", or similar).