Support `radius` in `content(frame: "rect")`

[janosh]

when fitting rectangular frames to content, would be great if you could apply a border radius. rect has that ability but content(frame: "rect") is not forwarding the radius

#import "@preview/cetz:0.3.1": canvas, draw

#set page(width: auto, height: auto, margin: 8pt)

#canvas({
  draw.content(
    (0, 0),
    [$hat(H)_"KS"=-frac(planck.reduce^2, 2m)arrow(nabla)^2 + v_("ext,s") (arrow(r))$],
    frame: "rect",
    stroke: .5pt,
    fill: rgb("#DCDCDC"),
    padding: 8pt,
    name: "hamiltonian",
    radius: 4pt, // currently has no effect, needs forwarding to rect
  )
})

[johannes-wolf]

I would prefer changing frame: to string or function and use something like frame: fit.rect.with(radius: ...).

Since we plan to change/add some kind of generic decoration to elements, frames could also implemented as some kind of decoration you can apply to an element.

[janosh]

agreed, that sounds like a much better API where that doesn't need individual arg forwarding and it's much clearer what the radius refers to

[noc0lour]

Is #541 the corresponding PR for the decorations changes? I'm interested in rounded corners for my text boxes and might want to get my feet wet helping to get some things moving :)

[johannes-wolf]

Is #541 the corresponding PR for the decorations changes? I'm interested in rounded corners for my text boxes and might want to get my feet wet helping to get some things moving :)

There is no PR open for this feature right now. I think I like the idea of having a fit namespace that provides some functions that can get called with a list of points and return a shape around those.

[noc0lour]

I realized that there is no PR for this specific issue, but in #541 are some changes w.r.t to the "generic decorations" mentioned here? #802 (comment)
Or is this issue entirely separate?

[johannes-wolf]

I realized that there is no PR for this specific issue, but in #541 are some changes w.r.t to the "generic decorations" mentioned here? #802 (comment) Or is this issue entirely separate?

Separate. And I do not think I ever merge #541 but instead move the changes over to #954.
The question is: Should frames around an element be path-modifiers/decorations?