From 4231233f76298fceac6037366ab78c8215fc770f Mon Sep 17 00:00:00 2001
From: LordBaryhobal <lordbaryhobal@gmail.com>
Date: Wed, 21 Jan 2026 16:17:23 +0100
Subject: [PATCH] fixed new participants not detected in syncs

fixes #20
---
 src/core/draw/sync.typ | 52 +++++++++++++++++++++++++-----------------
 src/core/renderer.typ  | 29 ++++++++---------------
 src/core/setup.typ     | 22 ++++++++++++++++++
 3 files changed, 63 insertions(+), 40 deletions(-)

diff --git a/src/core/draw/sync.typ b/src/core/draw/sync.typ
index b681947..050fe90 100644
--- a/src/core/draw/sync.typ
+++ b/src/core/draw/sync.typ
@@ -4,52 +4,62 @@
 #let render(sync) = get-ctx(ctx => {
   set-ctx(c => {
     c.sync = (
+      ctx: ctx,
       bottoms: (),
       starts: (),
-      y: ctx.y
+      start-y: ctx.y,
+      align-y: ctx.y
     )
+    c.in-sync = true
     return c
   })
+})
 
-  // Compute heights
+#let in-sync-render(elmt) = {
+  set-ctx(c => {
+    c.y = c.sync.start-y
+    return c
+  })
+  draw.hide({
+    (elmt.draw)(elmt)
+  })
+  set-ctx(c => {
+    c.sync.starts.push(c.last-drawn.start-info.y)
+    c.sync.bottoms.push(c.y)
+    return c
+  })
+}
+
+#let render-end(sync) = get-ctx(ctx => {
   for e in sync.elmts {
     assert(is-elmt(e), message: "Sync element can only contain chronos elements, found " + repr(e))
     assert(
       e.type == "seq",
       message: "Sync element can only contain sequences, found '" + e.type + "'"
     )
-
-    set-ctx(c => {
-      c.y = ctx.y
-      return c
-    })
-    draw.hide({
-      (e.draw)(e)
-    })
-    set-ctx(c => {
-      c.sync.starts.push(c.last-drawn.start-info.y)
-      c.sync.bottoms.push(c.y)
-      return c
-    })
   }
 
   set-ctx(c => {
-    c.sync-y = calc.min(..c.sync.starts)
-    return c
+    let new-sync = c.sync
+    if new-sync.starts.len() != 0 {
+      new-sync.align-y = calc.min(..new-sync.starts)
+    }
+    new-sync.remove("ctx")
+    return c.sync.ctx + (sync: new-sync)
   })
 
-  // Draw aligned elements
   for (i, e) in sync.elmts.enumerate() {
     set-ctx(c => {
-      let dy = c.sync.starts.at(i) - ctx.y
-      c.y = c.sync-y - dy
+      let dy = c.sync.starts.at(i) - c.sync.start-y
+      c.y = c.sync.align-y - dy
       return c
     })
     (e.draw)(e)
   }
 
   set-ctx(c => {
-    c.y = calc.min(..c.sync.bottoms)
+    let heights = c.sync.starts.zip(c.sync.bottoms).map(((s, b)) => b - s)
+    c.y = c.sync.align-y + calc.min(..heights)
     c.remove("sync")
     return c
   })
diff --git a/src/core/renderer.typ b/src/core/renderer.typ
index 1bb3297..14cf8d5 100644
--- a/src/core/renderer.typ
+++ b/src/core/renderer.typ
@@ -2,6 +2,7 @@
 
 #import "draw/note.typ": get-box as get-note-box, get-size as get-note-size
 #import "draw/participant.typ"
+#import "draw/sync.typ": in-sync-render
 #import "utils.typ": *
 #import "/src/consts.typ": *
 
@@ -15,22 +16,6 @@
   })
 }
 
-#let unwrap-syncs(elements) = {
-  let i = 0
-  while i < elements.len() {
-    let elmt = elements.at(i)
-    if elmt.type == "sync" {
-      elements = (
-        elements.slice(0, i + 1) +
-        elmt.elmts +
-        elements.slice(i + 1)
-      )
-    }
-    i += 1
-  }
-  return elements
-}
-
 #let seq-update-lifelines(participants, pars-i, seq) = {
   let participants = participants
   let com = if seq.comment == none {""} else {seq.comment}
@@ -308,7 +293,6 @@
 
 #let compute-columns-width(participants, elements, pars-i) = {
   elements = elements.filter(is-elmt)
-  elements = unwrap-syncs(elements)
 
   let cells
   (participants, elements, cells) = compute-max-lifeline-levels(participants, elements, pars-i)
@@ -334,7 +318,8 @@
     lifelines: participants.map(_ => (
       level: 0,
       lines: ()
-    ))
+    )),
+    in-sync: false
   )
   chronos-ctx.insert(
     "widths",
@@ -393,7 +378,13 @@
     if not is-elmt(elmt) {
       (elmt,)
     } else if "draw" in elmt and elmt.type != "par" {
-      (elmt.draw)(elmt)
+      get-ctx(ctx => {
+        if ctx.in-sync and elmt.type != "sync-end" {
+          in-sync-render(elmt)
+        } else {
+          (elmt.draw)(elmt)
+        }
+      })
     }
   }
 
diff --git a/src/core/setup.typ b/src/core/setup.typ
index 7873526..776b2bb 100644
--- a/src/core/setup.typ
+++ b/src/core/setup.typ
@@ -1,4 +1,5 @@
 #import "draw/group.typ": render-end as grp-render-end
+#import "draw/sync.typ": render-end as sync-render-end
 #import "utils.typ": get-group-span, is-elmt
 #import "/src/participant.typ": _exists as par-exists, _par
 #import "/src/sequence.typ": _seq
@@ -18,6 +19,24 @@
   )
 }
 
+#let flatten-sync(elmts, i) = {
+  let sync = elmts.at(i)
+  elmts.at(i) = sync
+  let start = sync
+  start.remove("elmts")
+  return (
+    elmts.slice(0, i) +
+    (start,) +
+    sync.elmts +
+    ((
+      type: "sync-end",
+      draw: sync-render-end,
+      elmts: sync.elmts
+    ),) +
+    elmts.slice(i + 1)
+  )
+}
+
 #let update-group-children(elmts, i) = {
   let elmts = elmts
   let group-end = elmts.at(i)
@@ -58,6 +77,9 @@
 
     if elmt.type == "grp" {
       elmts = flatten-group(elmts, i)
+    
+    } else if elmt.type == "sync" {
+      elmts = flatten-sync(elmts, i)
 
     } else if elmt.type == "seq" {
       if elmt.enable-dst {