Table of Contents / Outline: Treat Cover Images as H2-level headings

[mcsf]

Fixes #4606

Description

I don't know if this is functionality that we want. I think it makes sense to have, in some form or another, Gutenberg recognizing cover images as some form of document hierarchy. Feel free to close this PR and its parent issue if this isn't the way to go.

Caveat: #3444 is in progress and might change the circumstances. The present PR may be a temporary improvement. I also think it conceivable that Cover Image would offer different heading levels.

Screenshots (jpeg or gifs if applicable):

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code has proper inline documentation.

[jasmussen]

Nice! I think this one should definitely be counted, don't you agree @afercia?

I reckon that the Cover Image, while it can be used for decoration only, will often be used in the same way as a heading would.

It also seems to work largely as intended:

One questions though: should a heading be counted if you do not type anything into the H2? Or to phrase it differently, should the Cover Image block not output the H2 tag into the markup if you don't type anything?

A different question surfaces: right now a placeholder block for the Cover Image actually outputs a gray square in the saved source. Should the placeholder output anything at all? And if we made it not output anything, should the placeholder not count towards the headings?

[afercia]

Hm, not sure. #3444 is going to change the h2 to a p because we can't predict ho users will use a cover image. Headings should identify a section of content. What it the cover image is used just visually and immediately followed by another heading? In this case, the fact the cover image outputs a heading would be pointless, as it doesn't identify any content. /cc @samikeijonen

Id also like to remind there shouldn't be any hardcoded heading level in the output. Themes may use a different heading hierarchy and we can't assume a h2 will fit in the hierarchy. Ideally, as WordPress does, any HTML output should be filterable...

should the Cover Image block not output the H2 tag into the markup if you don't type anything?

Empty headings are evil 🙂

[samikeijonen]

I'd also like to remind there shouldn't be any hardcoded heading level in the output. Themes may use a different heading hierarchy and we can't assume a h2 will fit in the hierarchy.

This was the reason why #3444 uses <p>.

And +100+1 for not outputting any empty markup.

[jasmussen]

Converting the H2 to P is fine so long as it visually is unchanged. Same for not outputting empty markup.

In both those cases, it seems like we have an answer to this PR, though, which is to not count the Cover Image as a heading.

Thanks a whole bunch for exploring this, though, Miguel! 🏅

[mcsf]

My pleasure!