Add triangle shape

[moritzketzer]

I need a triangle shape for my diagrams, but I don't have the time to learn cetz and fletcher to add it myself (I tried, but it was not possible to label the node).

Could you add a triangle shape or show me how I can define a triangle shape myself according to the rules that fletcher accepts? That would be much appreciated!

[Jollywatt]

#import "@preview/fletcher:0.4.4": diagram, node, edge, cetz

#let triangle(node, extrude) = {
  let (w, h) = node.size
  w += 2*extrude
  h += 2*extrude
  cetz.draw.line(
    (-w, -h/2),
    (+w, -h/2),
    (0, +h),
    close: true
  )
}
#diagram(
  node-stroke: 1pt,
  node-outset: 3pt,
  node((0,0), [Hello,\ World!], shape: triangle),
  edge("->"),
  node((1,1), $a b c$, shape: triangle, extrude: (0, -2))
)

The only trick here is how the extrude distance is added to the node size, to support node extrude and outset

[moritzketzer]

Thank you so much! :)