[Feature Request]: Logo in Revealjs could be clickable

[ginolhac]

Hi,
In Quarto websites, all pages offer the navbar except slides. Meaning that once in a slide deck we cannot easily return to the website. That was feasible using {xaringanExtra} logo.
I was thinking about this kind of feature that would enable the logo to be a link:

---
title: "click logo"
format: 
  revealjs:
    logo: 
      file: https://www.r-project.org/logo/Rlogo.svg
      href: https://www.r-project.org
---

Or a markdown code :

 logo: [https://www.r-project.org/logo/Rlogo.svg](https://www.r-project.org)

I could be using an universal footer but I often use them to comment on the content of a specific slide.

Many thanks for this amazing tool!

[RoyiAvital]

I was also asking for this. It would be great to parse the logo as MarkDown.

[ginolhac]

Of note, on SO there is a Javascript solution posted https://stackoverflow.com/a/76812408/1395352

[mcanouil]

Extension template is one way to achieve that, possibly using a Lua filter, see https://quarto.org/docs/journals/templates.html#revealjs-partials.

A simple JavaScript solution:

---
title: "Quarto Playground"
format: revealjs
logo: https://quarto.org/quarto.png
include-after-body:
  - text: |
      <script type="text/javascript">
        window.addEventListener('load', function() {
          var logo = document.querySelector('.slide-logo');
          var url = 'https://quarto.org';
          logo.addEventListener('click', function() {
            window.open(url, '_blank');
          });
        });
      </script>
---

## Slide 1

This is a playground for Quarto.

[ginolhac]

Many thanks @mcanouil !
the javascript solution works, I can include it to all slides via an extension.
Could you maybe guide me a bit for how to get var url = 'https://quarto.org'; to read from a yaml header variable?
I have tried var url = $logo_url-meta$; (after proper assignment, but even $author-meta$ like in the template.html does not work) but without success.
Many thanks again

[cderv]

Just idea using Quarto Lua API:

• You can use Lua to add to includes like after-body: https://quarto.org/docs/extensions/lua-api.html#includes
• You could use Lua read the meta you want set a variable in Lua
• You could use that variable to fill your template script and use the API mentioned above to insert in document.

I have tried var url = $logo_url-meta$;

If you tried to add that in the text provided inside YAML, this won't work. It could work if you add the script directly in a template partials or template file that pandoc would resolve as a template. When include-after-body is resolved, it is too late and content is inserted as is.

[ginolhac]

I see, it is too late, I need to generate the template.html via a lua filter. I will try this option, thanks Christophe!

[mcanouil]

I was lazy so I did not add the Lua layer but definitely a good way to go for a custom format extension.

Note that I believe, it could be supported natively in Quarto in the future.

[ginolhac]

it's working! No partials but using @mcanouil JS code and a lua filter that takes the variable from the header before including the js code in the quarto HTML.
thanks again for the great help.