Image alt text compatible with Quarto and Pandoc

[dmca-glasgow]

Description

Hello,

As mentioned previously, I'm creating an accessibility tool which integrates Quarto. At this stage, this means converting LaTeX syntax to it's Quarto Markdown equivalent. Quarto was chosen partly for it's close integration of Pandoc, as being able to easily convert documents to other formats can be useful in an accessibility context.

I'm currently working on images/figures. I've noticed this difference between Quarto and Pandoc:

Given the following Markdown:

![My **caption** text](image.png){alt="My alt text"}

$ pandoc -f markdown -t html <<< "\![My **caption** text](image.png){alt=\"My alt text\"}"
<figure>
<img src="image.png" alt="My alt text" />
<figcaption>My <strong>caption</strong> text</figcaption>
</figure>

With Quarto:

<div class="quarto-figure quarto-figure-center">
  <figure class="figure">
    <p><img src="image.png" class="img-fluid figure-img"></p>
    <figcaption>My <strong>caption</strong> text</figcaption>
  </figure>
</div>

The image alt text is removed in the Quarto version.

Using fig-alt from the Quarto documentation outputs:

$ pandoc -f markdown -t html <<< "\![My **caption** text](image.png){fig-alt=\"My alt text\"}"
<figure>
<img src="image.png" data-fig-alt="My alt text" alt="My caption text" />
<figcaption aria-hidden="true">My <strong>caption</strong> text</figcaption>
</figure>

Which is equivalent to (without the data attribute):

$ pandoc -f markdown -t html <<< "\![My **caption** text](image.png)"                         
<figure>
<img src="image.png" alt="My caption text" />
<figcaption aria-hidden="true">My <strong>caption</strong> text</figcaption>
</figure>

And Quarto now behaves as intended:

<div class="quarto-figure quarto-figure-center">
  <figure class="figure">
    <p><img src="image.png" class="img-fluid figure-img" alt="My alt text"></p>
    <figcaption>My <strong>caption</strong> text</figcaption>
  </figure>
</div>

Is there a Markdown syntax I can use in both Quarto and Pandoc to provide HTML image alt text?

Thanks.

[mcanouil]

I don't think so because this is a side effect of the "figure" definition which differs between Quarto and Pandoc. This was needed for cross-reference and cross-formats.

As mentioned previously,

Accessibility: For better accessibility, please ensure link text is descriptive and meaningful rather than using generic terms such as "here". This helps all users understand the link's destination. See Writing meaningful link text (WCAG).

[dmca-glasgow]

Would you be open to supporting the alt property such as:

const alt = attributes['fig-alt'] || attibutes.alt || '';

I'll try a PR if so. Thanks

[mcanouil]

You can try to make the changes in a local clone, run the tests and possibly add some to ensure it does not break anything (see running tests). I'm not maintaining/reviewing PRs. The only thing I can say is: PRs are welcome but no guarantee that they will be approved.

[cscheid]

@dmca-glasgow We need to run our tests and think about it a little bit, but on the face of it, your suggestion makes sense. Let me know if you need help with the PR, and thank you!