Any way to set global mermaid chunk options?

[cjdbarlow]

Description

I would like to define chunk options for styling all mermaid diagrams created in the document, rather than having to manually do it each time. For example, I would like all graphs to use the stepBefore curve style. I can achieve this manually with:

```{mermaid}
%%{ init: { 'flowchart': { 'curve': 'stepBefore' } } }%%

graph_goes_here
```

But this distracts from the focus of the source document, which should be (imo) content rather than styling. I note similar things have been raised before so I am not sure if this is doable? Is there a way to prepend text to different code chunks?

[jimjam-slam]

I'm not sure if you can directly inject Mermaid defaults into document YAML, but you can either set a theme or override the theme defaults from the YAML using SASS variables that Quarto provides. That might not be enough for non-CSS configuration options like using stepBefore, though!

[cjdbarlow]

Thanks @jimjam-slam - you're right that they only allow for CSS configuration though. As far as I can work out, they also only work when you are serving the native JS and the rendering occurs client-side, and I'd like to display the graphs both when javascript is disabled and a non-HTML output format is used.

[cscheid]

This is something we could add to the baseline mermaid feature. We have our plates very full at the moment, but I'l create an enhancement ticket for it.

[cscheid]

See #7295