added some styling options

gallery/example1.typ

@@ -12,8 +12,14 @@ Alice <-- Bob: Another authentication Response
 #chronos.diagram({
   import "/src/diagram.typ": *
   _seq("Alice", "Bob", comment: "Authentication Request")
-  _seq("Bob", "Alice", comment: "Authentication Response", style: "dashed")
+  _seq("Bob", "Alice", comment: "Authentication Response", dashed: true)
   
   _seq("Alice", "Bob", comment: "Another authentication Request")
-  _seq("Bob", "Alice", comment: "Another authentication Response", style: "dashed")
+  _seq("Bob", "Alice", comment: "Another authentication Response", dashed: true)
+})
+
+#chronos.diagram({
+  import "/src/diagram.typ": *
+  _seq("Bob", "Alice", comment: "bonjour", color: red)
+  _seq("Alice", "Bob", comment: "ok", color: blue)
 })

src/diagram.typ

@@ -1,12 +1,21 @@
 #import "renderer.typ": render
 
-#let _seq(p1, p2, comment: none, style: auto) = {
+#let _seq(
+  p1,
+  p2,
+  comment: none,
+  dashed: false,
+  tip: "default",
+  color: black
+) = {
   return ((
     type: "seq",
     p1: p1,
     p2: p2,
     comment: comment,
-    style: style
+    dashed: dashed,
+    tip: tip,
+    color: color,
   ),)
 }
 

src/renderer.typ

@@ -1,7 +1,7 @@
 #import "@preview/cetz:0.2.2": canvas, draw
 
 #let X-SPACE = 2
-#let Y-SPACE = 30
+#let Y-SPACE = 20
 
 #let get-participants-i(participants) = {
   let pars-i = (:)
@@ -69,10 +69,18 @@
     if elmt.type == "seq" {
       let x1 = x-pos.at(pars-i.at(elmt.p1))
       let x2 = x-pos.at(pars-i.at(elmt.p2))
+      let style = (
+        mark: (end: "straight"),
+        stroke: (
+          dash: if elmt.dashed {"dashed"} else {"solid"},
+          paint: elmt.color
+        )
+      )
+
       draw.line(
         (x1, y),
         (x2, y),
-        mark: (end: "straight")
+        ..style
       )
       if elmt.comment != none {
         draw.content(