restructured code in separated files

gallery/example1.typ

@@ -10,7 +10,7 @@ Alice <-- Bob: Another authentication Response
 
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Alice", "Bob", comment: "Authentication Request")
   _seq("Bob", "Alice", comment: "Authentication Response", dashed: true)
   
@@ -19,19 +19,19 @@ Alice <-- Bob: Another authentication Response
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Bob", "Alice", comment: "bonjour", color: red)
   _seq("Alice", "Bob", comment: "ok", color: blue)
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Alice", "Bob", comment: "This is a test")
   _seq("Alice", "Callum", comment: "This is another test with a long text")
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Alice", "Bob", comment: "Authentication Request")
   _seq("Bob", "Alice", comment: "Authentication Failure")
 
@@ -45,7 +45,7 @@ Alice <-- Bob: Another authentication Response
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _sep("Initialization")
   _seq("Alice", "Bob", comment: "Authentication Request")
   _seq("Bob", "Alice", comment: "Authentication Response", dashed: true)
@@ -56,7 +56,7 @@ Alice <-- Bob: Another authentication Response
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Alice", "Bob", comment: "message 1")
   _seq("Bob", "Alice", comment: "ok", dashed: true)
   _gap()
@@ -68,7 +68,7 @@ Alice <-- Bob: Another authentication Response
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("Alice", "Alice", comment: "On the\nright")
   _seq("Alice", "Alice", flip: true, comment: "On the\nleft")
 })

gallery/example2.typ

@@ -2,7 +2,7 @@
 
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("User", "A", comment: "DoWork", enable-dst: true)
   _seq("A", "B", comment: [#sym.quote.angle.l createRequest #sym.quote.angle.r], enable-dst: true)
   _seq("B", "C", comment: "DoWork", enable-dst: true)
@@ -12,7 +12,7 @@
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("User", "A", comment: "DoWork", enable-dst: true)
   _seq("A", "A", comment: "Internal call", enable-dst: true)
   _seq("A", "B", comment: [#sym.quote.angle.l createRequest #sym.quote.angle.r], enable-dst: true)
@@ -21,7 +21,7 @@
 })
 
 #chronos.diagram({
-  import "/src/diagram.typ": *
+  import chronos: *
   _seq("alice", "bob", comment: "hello", enable-dst: true)
   _seq("bob", "bob", comment: "self call", enable-dst: true)
   _seq("bill", "bob", comment: "hello from thread 2", enable-dst: true)
@@ -30,4 +30,11 @@
   _seq("bob", "bob", comment: "rc", disable-src: true, dashed: true)
   _seq("bob", "george", comment: "delete", destroy-dst: true)
   _seq("bob", "alice", comment: "success", disable-src: true, dashed: true)
+})
+
+#chronos.diagram({
+  import chronos: *
+  _seq("alice", "bob", comment: "hello1", enable-dst: true)
+  _seq("bob", "charlie", comment: "hello2", enable-dst: true, disable-src: true)
+  _seq("charlie", "alice", comment: "ok", dashed: true, disable-src: true)
 })

src/consts.typ

@@ -0,0 +1,5 @@
+#let Y-SPACE = 10
+#let PAR-PAD = (5pt, 3pt)
+#let PAR-SPACE = 10
+#let COMMENT-PAD = 8
+#let LIFELINE-W = 10

src/diagram.typ

@@ -1,71 +1,6 @@
 #import "utils.typ": get-group-span
 #import "renderer.typ": render
-
-#let _seq(
-  p1,
-  p2,
-  comment: none,
-  dashed: false,
-  tip: "default",
-  color: black,
-  flip: false,
-  enable-dst: false,
-  disable-dst: false,
-  destroy-dst: false,
-  disable-src: false,
-  destroy-src: false,
-) = {
-  return ((
-    type: "seq",
-    p1: p1,
-    p2: p2,
-    comment: comment,
-    dashed: dashed,
-    tip: tip,
-    color: color,
-    flip: flip,
-    enable-dst: enable-dst,
-    disable-dst: disable-dst,
-    destroy-dst: destroy-dst,
-    disable-src: disable-src,
-    destroy-src: destroy-src,
-  ),)
-}
-
-#let _par(name, display-name: auto, start-at: 0) = {
-  return ((
-    type: "par",
-    name: name,
-    display-name: if display-name == auto {name} else {display-name},
-    start-at: start-at
-  ),)
-}
-
-#let _par-exists(participants, name) = {
-  for p in participants {
-    if name == p.name {
-      return true
-    }
-  }
-  return false
-}
-
-#let _grp(name, desc: none, type: "default", elmts) = {
-  return ((
-    type: "grp",
-    name: name,
-    desc: desc,
-    grp-type: type,
-    elmts: elmts
-  ),)
-}
-
-#let _sep(name) = {
-  return ((
-    type: "sep",
-    name: name
-  ),)
-}
+#import "participant.typ" as participant: _par
 
 #let _gap(size: 20) = {
   return ((
@@ -78,6 +13,8 @@
   let participants = ()
   let elmts = elements
   let i = 0
+
+  // Flatten groups
   while i < elmts.len() {
     let elmt = elmts.at(i)
     if elmt.type == "grp" {
@@ -93,19 +30,21 @@
     i += 1
   }
 
+  // List participants
   for elmt in elmts {
     if elmt.type == "par" {
       participants.push(elmt)
     } else if elmt.type == "seq" {
-      if not _par-exists(participants, elmt.p1) {
+      if not participant._exists(participants, elmt.p1) {
         participants.push(_par(elmt.p1).first())
       }
-      if not _par-exists(participants, elmt.p2) {
+      if not participant._exists(participants, elmt.p2) {
         participants.push(_par(elmt.p2).first())
       }
     }
   }
 
+  // Compute groups spans (horizontal)
   for (i, elmt) in elmts.enumerate() {
     if elmt.type == "grp" {
       let (min-i, max-i) = get-group-span(participants, elmt)

src/group.typ

@@ -0,0 +1,52 @@
+#import "@preview/cetz:0.2.2": draw
+
+#let _grp(name, desc: none, type: "default", elmts) = {
+  return ((
+    type: "grp",
+    name: name,
+    desc: desc,
+    grp-type: type,
+    elmts: elmts
+  ),)
+}
+
+#let render(x0, x1, y0, y1, group) = {
+  let shapes = ()
+  let m = measure(box(group.name))
+  let w = m.width / 1pt + 15
+  let h = m.height / 1pt + 6
+  shapes += draw.rect(
+    (x0, y0),
+    (x1, y1)
+  )
+  shapes += draw.merge-path(
+    fill: gray.lighten(20%),
+    close: true,
+    {
+      draw.line(
+        (x0, y0),
+        (x0 + w, y0),
+        (x0 + w, y0 - h / 2),
+        (x0 + w - 5, y0 - h),
+        (x0, y0 - h)
+      )
+    }
+  )
+  shapes += draw.content(
+    (x0, y0),
+    group.name,
+    anchor: "north-west",
+    padding: (left: 5pt, right: 10pt, top: 3pt, bottom: 3pt)
+  )
+
+  if group.desc != none {
+    shapes += draw.content(
+      (x0 + w, y0),
+      text([\[#group.desc\]], weight: "bold"),
+      anchor: "north-west",
+      padding: 3pt
+    )
+  }
+
+  return shapes
+}

src/lib.typ

@@ -1 +1,6 @@
-#import "diagram.typ": diagram, from-plantuml
+#import "diagram.typ": diagram, from-plantuml, _gap
+
+#import "sequence.typ": _seq
+#import "group.typ": _grp
+#import "participant.typ": _par
+#import "separator.typ": _sep

src/participant.typ

@@ -0,0 +1,17 @@
+#let _par(name, display-name: auto, start-at: 0) = {
+  return ((
+    type: "par",
+    name: name,
+    display-name: if display-name == auto {name} else {display-name},
+    start-at: start-at
+  ),)
+}
+
+#let _exists(participants, name) = {
+  for p in participants {
+    if name == p.name {
+      return true
+    }
+  }
+  return false
+}

src/renderer.typ

@@ -1,11 +1,9 @@
 #import "@preview/cetz:0.2.2": canvas, draw
 #import "utils.typ": get-participants-i
-
-#let Y-SPACE = 10
-#let PAR-PAD = (5pt, 3pt)
-#let PAR-SPACE = 10
-#let COMMENT-PAD = 8
-#let LIFELINE-W = 10
+#import "group.typ"
+#import "sequence.typ"
+#import "separator.typ"
+#import "consts.typ": *
 
 
 #let get-columns-width(participants, elements) = {
@@ -16,6 +14,8 @@
   })
   let pars-i = get-participants-i(participants)
   let cells = ()
+
+  // Compute max lifeline levels
   for elmt in elements {
     if elmt.type == "seq" {
       let com = if elmt.comment == none {""} else {elmt.comment}
@@ -49,6 +49,8 @@
     }
   }
 
+  // Compute column widths
+  // Compute minimum widths for participant names
   let widths = ()
   for i in range(participants.len() - 1) {
     let p1 = participants.at(i)
@@ -58,6 +60,7 @@
     widths.push(w1 / 2pt + w2 / 2pt + PAR-SPACE)
   }
 
+  // Compute minimum width for simple sequences (spanning 1 column)
   for cell in cells.filter(c => c.i2 - c.i1 == 1) {
     let m = measure(cell.cell)
     widths.at(cell.i1) = calc.max(
@@ -66,6 +69,7 @@
     )
   }
 
+  // Compute remaining widths for longer sequences (spanning multiple columns)
   let multicol-cells = cells.filter(c => c.i2 - c.i1 > 1)
   multicol-cells = multicol-cells.sorted(key: c => {
     c.i1 * 1000 + c.i2
@@ -77,6 +81,8 @@
       m.width / 1pt - widths.slice(0, cell.i2 - 1).sum()
     )
   }
+
+  // Add lifeline widths
   for (i, w) in widths.enumerate() {
     let p1 = participants.at(i)
     let p2 = participants.at(i + 1)
@@ -89,57 +95,21 @@
   return widths
 }
 
-#let draw-group(x0, x1, y0, y1, group) = {
-  let m = measure(box(group.name))
-  let w = m.width / 1pt + 15
-  let h = m.height / 1pt + 6
-  draw.rect(
-    (x0, y0),
-    (x1, y1)
-  )
-  draw.merge-path(
-    fill: gray.lighten(20%),
-    close: true,
-    {
-      draw.line(
-        (x0, y0),
-        (x0 + w, y0),
-        (x0 + w, y0 - h / 2),
-        (x0 + w - 5, y0 - h),
-        (x0, y0 - h)
-      )
-    }
-  )
-  draw.content(
-    (x0, y0),
-    group.name,
-    anchor: "north-west",
-    padding: (left: 5pt, right: 10pt, top: 3pt, bottom: 3pt)
-  )
-
-  if group.desc != none {
-    draw.content(
-      (x0 + w, y0),
-      text([\[#group.desc\]], weight: "bold"),
-      anchor: "north-west",
-      padding: 3pt
-    )
-  }
-}
-
 #let render(participants, elements) = context canvas(length: 1pt, {
+  let shapes = ()
   let pars-i = get-participants-i(participants)
 
   let widths = get-columns-width(participants, elements)
 
+  // Compute each column's X position
   let x-pos = (0,)
   for width in widths {
     x-pos.push(x-pos.last() + width)
   }
   
-  // Draw participants
+  // Draw participants (start)
   for (i, p) in participants.enumerate() {
-    draw.content(
+    shapes += draw.content(
       (x-pos.at(i), 0),
       p.display-name,
       name: p.name,
@@ -156,124 +126,23 @@
     lines: ()
   ))
 
-  // Draw sequences
+  let draw-seq = sequence.render.with(pars-i, x-pos)
+  let draw-group = group.render.with()
+  let draw-sep = separator.render.with(x-pos)
+
+  // Draw elemnts
   for elmt in elements {
+    // Sequences
     if elmt.type == "seq" {
-      let i1 = pars-i.at(elmt.p1)
-      let i2 = pars-i.at(elmt.p2)
-
-      if elmt.comment != none {
-        y -= measure(box(elmt.comment)).height / 1pt + 6
-      }
-
-      if elmt.disable-src {
-        let src-line = lifelines.at(i1)
-        src-line.level -= 1
-        src-line.lines.push(("disable", y, auto))
-        lifelines.at(i1) = src-line
-      }
-      if elmt.destroy-src {
-        let src-line = lifelines.at(i1)
-        src-line.level -= 1
-        src-line.lines.push(("destroy", y, auto))
-        lifelines.at(i1) = src-line
-      }
-
-      let ll-lvl1 = lifelines.at(i1).level * LIFELINE-W / 2
-
-      if elmt.disable-dst {
-        let dst-line = lifelines.at(i2)
-        dst-line.level -= 1
-        dst-line.lines.push(("disable", y, auto))
-        lifelines.at(i2) = dst-line
-      }
-      if elmt.destroy-dst {
-        let dst-line = lifelines.at(i2)
-        dst-line.level -= 1
-        dst-line.lines.push(("destroy", y, auto))
-        lifelines.at(i2) = dst-line
-      }
-      if elmt.enable-dst {
-        let dst-line = lifelines.at(i2)
-        dst-line.level += 1
-        lifelines.at(i2) = dst-line
-      }
-
-      let x1 = x-pos.at(i1)
-      let x2 = x-pos.at(i2)
-
-      let ll-lvl2 = lifelines.at(i2).level * LIFELINE-W / 2
-
-      let f = if elmt.flip {-1} else {1}
-      if i1 <= i2 {
-        x1 += ll-lvl1 * f
-        x2 -= ll-lvl2 * f
-      } else {
-        x1 -= ll-lvl1 * f
-        x2 += ll-lvl2 * f
-      }
-
-      let style = (
-        mark: (end: "straight"),
-        stroke: (
-          dash: if elmt.dashed {"dashed"} else {"solid"},
-          paint: elmt.color
-        )
-      )
-
-      if elmt.p1 == elmt.p2 {
-        let x3 = x1 - ll-lvl1 + ll-lvl2
-
-        x2 = if elmt.flip {x1 - 20} else {x1 + 20}
-
-        if elmt.comment != none {
-          draw.content(
-            (x1, y),
-            elmt.comment,
-            anchor: if elmt.flip {"south-east"} else {"south-west"},
-            padding: 3pt
-          )
-        }
-
-        draw.line(
-          (x1, y),
-          (x2, y),
-          (x2, y - 10),
-          (x3, y - 10),
-          ..style
-        )
-        y -= 10
-
-      } else {
-        if elmt.comment != none {
-          let x = calc.min(x1, x2)
-          if x2 < x1 {
-            x += COMMENT-PAD
-          }
-          draw.content(
-            (x, y),
-            elmt.comment,
-            anchor: "south-west",
-            padding: 3pt
-          )
-        }
-
-        draw.line(
-          (x1, y),
-          (x2, y),
-          ..style
-        )
-      }
-      if elmt.enable-dst {
-        let dst-line = lifelines.at(i2)
-        dst-line.lines.push(("enable", y, auto))
-        lifelines.at(i2) = dst-line
-      }
-      y -= Y-SPACE
+      let shps
+      (y, lifelines, shps) = draw-seq(elmt, y, lifelines)
+      shapes += shps
 
+    // Groups (start) -> reserve space for labels + store position
     } else if elmt.type == "grp" {
       let m = measure(
         box(
+          elmt.name,
           inset: (left: 5pt, right: 5pt, top: 3pt, bottom: 3pt),
         )
       )
@@ -285,53 +154,33 @@
       groups.push((y, elmt, 0, 0))
       y -= m.height / 1pt + Y-SPACE
     
+    // Groups (end) -> actual drawing
     } else if elmt.type == "grp-end" {
       let (start-y, group, start-lvl, end-lvl) = groups.pop()
       let x0 = x-pos.at(group.min-i) - start-lvl * 10 - 20
       let x1 = x-pos.at(group.max-i) + end-lvl * 10 + 20
-      draw-group(x0, x1, start-y, y, group)
+      shapes += draw-group(x0, x1, start-y, y, group)
 
       y -= Y-SPACE
 
+    // Separator
     } else if elmt.type == "sep" {
-      let x0 = x-pos.first() - 20
-      let x1 = x-pos.last() + 20
-      let m = measure(
-        box(
-          elmt.name,
-          inset: (left: 3pt, right: 3pt, top: 5pt, bottom: 5pt)
-        )
-      )
-      let w = m.width / 1pt
-      let h = m.height / 1pt
-      let cx = (x0 + x1) / 2
-      let xl = cx - w / 2
-      let xr = cx + w / 2
-
-      y -= h / 2
-      draw.line((x0, y), (xl, y))
-      draw.line((xr, y), (x1, y))
-      y -= 3
-      draw.line((x0, y), (xl, y))
-      draw.line((xr, y), (x1, y))
-      draw.content(
-        ((x0 + x1) / 2, y + 1.5),
-        elmt.name,
-        anchor: "center",
-        padding: (5pt, 3pt),
-        frame: "rect"
-      )
-      y -= h / 2
-      y -= Y-SPACE
+      let shps
+      (y, shps) = draw-sep(elmt, y)
+      shapes += shps
+    
+    // Gap
     } else if elmt.type == "gap" {
       y -= elmt.size
     }
   }
 
-  // Draw vertical lines + end participants
-  draw.on-layer(-1, {
+  // Draw vertical lines + lifelines + end participants
+  shapes += draw.on-layer(-1, {
     for (i, p) in participants.enumerate() {
       let x = x-pos.at(i)
+
+      // Draw vertical line
       draw.line(
         (x, 0),
         (x, y),
@@ -341,10 +190,13 @@
       let rects = ()
       let destructions = ()
       let lines = ()
+
+      // Compute lifeline rectangles + destruction positions
       for line in lifelines.at(i).lines {
         let event = line.first()
         if event == "enable" {
           lines.push(line)
+        
         } else if event == "disable" or event == "destroy" {
           let l = lines.pop()
           let lvl = lines.len()
@@ -355,19 +207,23 @@
         }
       }
 
+      // Draw lifeline rectangles (reverse for bottom to top)
       for rect in rects.rev() {
         let (cx, y0, y1) = rect
         draw.rect(
           (cx - LIFELINE-W / 2, y0),
-          (cx + LIFELINE-W / 2, y1),
+          (cx + LIFELINE-W / 2, y1)
         )
       }
+
+      // Draw lifeline destructions
       for dest in destructions {
         let (cx, cy) = dest
         draw.line((cx - 8, cy - 8), (cx + 8, cy + 8), stroke: red + 2pt)
         draw.line((cx - 8, cy + 8), (cx + 8, cy - 8), stroke: red + 2pt)
       }
 
+      // Draw participants (end)
       draw.content(
         (x, y),
         p.display-name,
@@ -378,4 +234,6 @@
       )
     }
   })
+
+  shapes
 })

src/separator.typ

@@ -0,0 +1,46 @@
+#import "@preview/cetz:0.2.2": draw
+#import "consts.typ": *
+
+#let _sep(name) = {
+  return ((
+    type: "sep",
+    name: name
+  ),)
+}
+
+#let render(x-pos, elmt, y) = {
+  let shapes = ()
+
+  let x0 = x-pos.first() - 20
+  let x1 = x-pos.last() + 20
+  let m = measure(
+    box(
+      elmt.name,
+      inset: (left: 3pt, right: 3pt, top: 5pt, bottom: 5pt)
+    )
+  )
+  let w = m.width / 1pt
+  let h = m.height / 1pt
+  let cx = (x0 + x1) / 2
+  let xl = cx - w / 2
+  let xr = cx + w / 2
+
+  y -= h / 2
+  shapes += draw.line((x0, y), (xl, y))
+  shapes += draw.line((xr, y), (x1, y))
+  y -= 3
+  shapes += draw.line((x0, y), (xl, y))
+  shapes += draw.line((xr, y), (x1, y))
+  shapes += draw.content(
+    ((x0 + x1) / 2, y + 1.5),
+    elmt.name,
+    anchor: "center",
+    padding: (5pt, 3pt),
+    frame: "rect"
+  )
+  y -= h / 2
+  y -= Y-SPACE
+
+  let r = (y, shapes)
+  return r
+}

src/sequence.typ

@@ -0,0 +1,152 @@
+#import "consts.typ": *
+#import "@preview/cetz:0.2.2": draw
+
+#let _seq(
+  p1,
+  p2,
+  comment: none,
+  dashed: false,
+  tip: "default",
+  color: black,
+  flip: false,
+  enable-dst: false,
+  disable-dst: false,
+  destroy-dst: false,
+  disable-src: false,
+  destroy-src: false,
+) = {
+  return ((
+    type: "seq",
+    p1: p1,
+    p2: p2,
+    comment: comment,
+    dashed: dashed,
+    tip: tip,
+    color: color,
+    flip: flip,
+    enable-dst: enable-dst,
+    disable-dst: disable-dst,
+    destroy-dst: destroy-dst,
+    disable-src: disable-src,
+    destroy-src: destroy-src,
+  ),)
+}
+
+#let render(pars-i, x-pos, elmt, y, lifelines) = {
+  let shapes = ()
+
+  let i1 = pars-i.at(elmt.p1)
+  let i2 = pars-i.at(elmt.p2)
+
+  if elmt.comment != none {
+    y -= measure(box(elmt.comment)).height / 1pt + 6
+  }
+
+  if elmt.disable-src {
+    let src-line = lifelines.at(i1)
+    src-line.level -= 1
+    src-line.lines.push(("disable", y, auto))
+    lifelines.at(i1) = src-line
+  }
+  if elmt.destroy-src {
+    let src-line = lifelines.at(i1)
+    src-line.level -= 1
+    src-line.lines.push(("destroy", y, auto))
+    lifelines.at(i1) = src-line
+  }
+
+  let ll-lvl1 = lifelines.at(i1).level * LIFELINE-W / 2
+
+  if elmt.disable-dst {
+    let dst-line = lifelines.at(i2)
+    dst-line.level -= 1
+    dst-line.lines.push(("disable", y, auto))
+    lifelines.at(i2) = dst-line
+  }
+  if elmt.destroy-dst {
+    let dst-line = lifelines.at(i2)
+    dst-line.level -= 1
+    dst-line.lines.push(("destroy", y, auto))
+    lifelines.at(i2) = dst-line
+  }
+  if elmt.enable-dst {
+    let dst-line = lifelines.at(i2)
+    dst-line.level += 1
+    lifelines.at(i2) = dst-line
+  }
+
+  let x1 = x-pos.at(i1)
+  let x2 = x-pos.at(i2)
+
+  let ll-lvl2 = lifelines.at(i2).level * LIFELINE-W / 2
+
+  let f = if elmt.flip {-1} else {1}
+  if i1 <= i2 {
+    x1 += ll-lvl1 * f
+    x2 -= ll-lvl2 * f
+  } else {
+    x1 -= ll-lvl1 * f
+    x2 += ll-lvl2 * f
+  }
+
+  let style = (
+    mark: (end: "straight"),
+    stroke: (
+      dash: if elmt.dashed {"dashed"} else {"solid"},
+      paint: elmt.color
+    )
+  )
+
+  if elmt.p1 == elmt.p2 {
+    let x3 = x1 - ll-lvl1 + ll-lvl2
+
+    x2 = if elmt.flip {x1 - 20} else {x1 + 20}
+
+    if elmt.comment != none {
+      shapes += draw.content(
+        (x1, y),
+        elmt.comment,
+        anchor: if elmt.flip {"south-east"} else {"south-west"},
+        padding: 3pt
+      )
+    }
+
+    shapes += draw.line(
+      (x1, y),
+      (x2, y),
+      (x2, y - 10),
+      (x3, y - 10),
+      ..style
+    )
+    y -= 10
+
+  } else {
+    if elmt.comment != none {
+      let x = calc.min(x1, x2)
+      if x2 < x1 {
+        x += COMMENT-PAD
+      }
+      shapes += draw.content(
+        (x, y),
+        elmt.comment,
+        anchor: "south-west",
+        padding: 3pt
+      )
+    }
+
+    shapes += draw.line(
+      (x1, y),
+      (x2, y),
+      ..style
+    )
+  }
+  if elmt.enable-dst {
+    let dst-line = lifelines.at(i2)
+    dst-line.lines.push(("enable", y, auto))
+    lifelines.at(i2) = dst-line
+  }
+  y -= Y-SPACE
+
+  let r = (y, lifelines, shapes)
+  return r
+}