Neat, but you can just do this in mermaid too. Taking one of your examples:

  <mermaid>
  flowchart LR

  web([Frontend])

  subgraph platform [Cloud Platform]
    api([API Server])
    db[(Database)]
    api --> db
  end

  web -->|HTTPS| api
  </mermaid>

If you install the latest https://oj-hn.com , you can see it rendered inline here.

Fair point. I added basic mermaid parsing to the library so you can do that here too.

    $ echo 'flowchart LR
        web([Frontend])
        subgraph platform [Cloud Platform]
          api([API Server])
          db[(Database)]
          api --> db
        end
        web -->|HTTPS| api' | npx box-of-rain --mermaid

                           ╔══ Cloud Platform ════════════════════╗
                           ║                                      ║
    ╭──────────╮           ║  ╭────────────╮      ╔════════════╗  ║
    │          │           ║  │            │      ║            ║  ║
    │ Frontend │ ─── HTTPS ──▶│ API Server │ ────▶║  Database  ║  ║
    │          │           ║  │            │      ║            ║  ║
    ╰──────────╯           ║  ╰────────────╯      ╚════════════╝  ║
                           ╚══════════════════════════════════════╝

Nice work! Love it.

On my system the "right arrow" glyph is 2 units wide and breaks all the layouts.

First off, let me say it is awesome you're doing something like this.

But... I'm encountering a similar issue on both Chrome and Firefox on Leenucks. I guess it's possible you don't see the problem on your Mac because both these browsers use the OS to do font rendering.

TIL about ambiguous width unicode characters. Turns out some locales render these chars as double width. I'm attempting to work out a solution.

Seems like maybe there are some universal half-width characters that can be used.

https://www.unicode.org/reports/tr11/

Unfortunately even if you pick nominally-equal-width glyphs, on the web you can still get screwed over by font substitution/fallback done by the browser.

same in my Brave Browser, why not stick to nomal Ascii?

I'm just here for the Grateful Dead reference.

Holy moly -- you're behind Relisten, OP? I owe you a great debt of gratitude for the hours of musical joy Relisten has given me.

Yup! We’re just one link in the chain (bands, tapers, archivists, & the listeners), but I appreciate the sentiment. Alec and I have been running Relisten for over a decade and we’ve put a lot of work into it these past few years.

Had to give the Dead a little nod here

Too true! Feels extra nice to be able to spread the sentiment of gratitude so far and wide. Keep it up!