Add header docinfo support

[yann-soubeyrand]

Head, header and footer reveal.js docinfo, and footer docinfo are already supported. However, header docinfo is not, but may be useful to add a logo for example. It can also confuse users that this is not working like in other AsciiDoc documents (maybe head docinfo should be added as well).

[ggrossetie]

I would love your opinion on #466
Once we agree on which use cases are supported we can move forward and add the missing docinfo locations.

but may be useful to add a logo for example

The logo will appear on each slides? before the first slide? Could you please provide a simple example?

[yann-soubeyrand]

Hi @ggrossetie, sorry for the late reply. You can find an example here: https://github.com/camptocamp/asciidoctor-revealjs-template/blob/bf5d7c1cf9a91c6a9eb76a5200ff700270d34a56/docinfo-footer.html#L1-L6. There’s a presentation.html in this repo showing the result. It took me some time to figure out why I couldn’t get my logos when putting them in the docinfo-header.html file and I was surprised to discover that docinfo-footer.html was supported, but not the other docinfo-*.html. I can’t put my logos in docinfo-header-revealjs.html, because their position is wrong in this case.

[yann-soubeyrand]

As an (unrelated) side note, Font Awesome v6 seems to work with v4 shims: https://github.com/camptocamp/asciidoctor-revealjs-template/blob/example/css/font-awesome.css.

Edit: never mind, I thought I read that asciidoctor-revealjs was blocked on Font Awesome v4, but I may have read it in the asciidoctor issues, or maybe I’m just wrong!

Edit 2: yes, that’s it: asciidoctor/asciidoctor#2535!