refactored debug rendering

src/core/renderer.typ

@@ -353,6 +353,24 @@
   )
 },)
 
+#let render-debug() = get-ctx(ctx => {
+  for p in ctx.participants.filter(p => p.invisible) {
+    let color = if p.name.starts-with("?") {green} else if p.name.ends-with("?") {red} else {blue}
+    let x = ctx.x-pos.at(p.i)
+    draw.line(
+      (x, 0),
+      (x, ctx.y),
+      stroke: (paint: color, dash: "dotted")
+    )
+    draw.content(
+      (x, 0),
+      p.display-name,
+      anchor: "west",
+      angle: 90deg
+    )
+  }
+})
+
 #let render(participants, elements) = context canvas(length: 1pt, {
   setup-ctx(participants, elements)
   
@@ -379,24 +397,9 @@
     return ctx
   })
 
-  // Draw vertical lines + lifelines + end participants
   draw.on-layer(-1, {
     if DEBUG-INVISIBLE {
-      for p in participants.filter(p => p.invisible) {
+      render-debug()
-        let color = if p.name.starts-with("?") {green} else if p.name.ends-with("?") {red} else {blue}
-        let x = x-pos.at(p.i)
-        draw.line(
-          (x, 0),
-          (x, y),
-          stroke: (paint: color, dash: "dotted")
-        )
-        draw.content(
-          (x, 0),
-          p.display-name,
-          anchor: "west",
-          angle: 90deg
-        )
-      }
     }
     
     participant.render-lifelines()