refactored sequences, sync and gaps

src/core/draw/event.typ

@@ -0,0 +1,31 @@
+#import "../utils.typ": get-ctx, set-ctx
+#import "../../consts.typ": *
+
+#let render(evt) = get-ctx(ctx => {
+  let par-name = evt.participant
+  let i = ctx.pars-i.at(par-name)
+  let par = ctx.participants.at(i)
+  let line = ctx.lifelines.at(i)
+  let entry = (evt.event, ctx.y)
+
+  if evt.event == "disable" {
+    line.level -= 1
+  } else if evt.event == "enable" {
+    line.level += 1
+    entry.push(evt.lifeline-style)
+  } else if evt.event == "create" {
+    ctx.y -= CREATE-OFFSET
+    entry.at(1) = ctx.y
+    (par.draw)(par)
+  } else if evt.event == "destroy" {
+  } else {
+    panic("Unknown event '" + evt.event + "'")
+  }
+
+  line.lines.push(entry)
+  set-ctx(c => {
+    c.lifelines.at(i) = line
+    c.y = ctx.y
+    return c
+  })
+})