added participant creation

gallery/example2.typ

@@ -6,7 +6,7 @@
   _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)
-  _seq("C", "B", comment: "WorkDone", destroy-src: true, dashed: true)
+  _seq("C", "B", comment: "WorkDone", destroy-src: true, disable-src: true, dashed: true)
   _seq("B", "A", comment: "RequestCreated", disable-src: true, dashed: true)
   _seq("A", "User", comment: "Done", disable-src: true)
 })
@@ -38,3 +38,4 @@
   _seq("bob", "charlie", comment: "hello2", enable-dst: true, disable-src: true)
   _seq("charlie", "alice", comment: "ok", dashed: true, disable-src: true)
 })
+

src/diagram.typ

@@ -39,11 +39,18 @@
         participants.push(_par(elmt.p1).first())
       }
       if not participant._exists(participants, elmt.p2) {
-        participants.push(_par(elmt.p2).first())
+        let par = _par(elmt.p2, from-start: not elmt.create-dst).first()
+        participants.push(par)
       }
     }
   }
 
+  // Add index to participant
+  for (i, p) in participants.enumerate() {
+    p.insert("i", i)
+    participants.at(i) = p
+  }
+
   // Compute groups spans (horizontal)
   for (i, elmt) in elmts.enumerate() {
     if elmt.type == "grp" {

src/participant.typ

@@ -1,9 +1,12 @@
-#let _par(name, display-name: auto, start-at: 0) = {
+#import "@preview/cetz:0.2.2": draw
+#import "consts.typ": *
+
+#let _par(name, display-name: auto, from-start: true) = {
   return ((
     type: "par",
     name: name,
     display-name: if display-name == auto {name} else {display-name},
-    start-at: start-at
+    from-start: from-start
   ),)
 }
 
@@ -15,3 +18,14 @@
   }
   return false
 }
+
+#let render(x-pos, p, y: 0) = {
+  draw.content(
+    (x-pos.at(p.i), y),
+    p.display-name,
+    name: p.name,
+    frame: "rect",
+    padding: PAR-PAD,
+    anchor: "south"
+  )
+}

src/renderer.typ

@@ -1,6 +1,7 @@
 #import "@preview/cetz:0.2.2": canvas, draw
 #import "utils.typ": get-participants-i, get-style
 #import "group.typ"
+#import "participant.typ"
 #import "sequence.typ"
 #import "separator.typ"
 #import "consts.typ": *
@@ -107,16 +108,16 @@
     x-pos.push(x-pos.last() + width)
   }
 
+  let draw-seq = sequence.render.with(pars-i, x-pos, participants)
+  let draw-group = group.render.with()
+  let draw-sep = separator.render.with(x-pos)
+  let draw-par = participant.render.with(x-pos)
+  
   // Draw participants (start)
-  for (i, p) in participants.enumerate() {
-    shapes += draw.content(
-      (x-pos.at(i), 0),
-      p.display-name,
-      name: p.name,
-      frame: "rect",
-      padding: PAR-PAD,
-      anchor: "south"
-    )
+  for p in participants {
+    if p.from-start {
+      shapes += draw-par(p)
+    }
   }
 
   let y = -Y-SPACE
@@ -126,10 +127,6 @@
     lines: ()
   ))
 
-  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
@@ -181,11 +178,7 @@
       let x = x-pos.at(i)
 
       // Draw vertical line
-      draw.line(
-        (x, 0),
-        (x, y),
-        stroke: (dash: "dashed", paint: gray.darken(40%))
-      )
+      let last-y = 0
 
       let rects = ()
       let destructions = ()
@@ -194,19 +187,45 @@
       // Compute lifeline rectangles + destruction positions
       for line in lifelines.at(i).lines {
         let event = line.first()
-        if event == "enable" {
+        if event == "create" {
+          last-y = line.at(1)
+
+        } else if event == "enable" {
+          if lines.len() == 0 {
+            draw.line(
+              (x, last-y),
+              (x, line.at(1)),
+              stroke: (dash: "dashed", paint: gray.darken(40%))
+            )
+          }
           lines.push(line)
         
         } else if event == "disable" or event == "destroy" {
+          let lvl = 0
+          if lines.len() != 0 {
             let l = lines.pop()
-          let lvl = lines.len()
-          rects.push((x + lvl * LIFELINE-W / 2, l.at(1), line.at(1)))
+            lvl = lines.len()
+            rects.push((
+              x + lvl * LIFELINE-W / 2,
+              l.at(1),
+              line.at(1),
+              l.at(2)
+            ))
+            last-y = line.at(1)
+          }
+
           if event == "destroy" {
             destructions.push((x + lvl * LIFELINE-W / 2, line.at(1)))
           }
         }
       }
 
+      draw.line(
+        (x, last-y),
+        (x, y),
+        stroke: (dash: "dashed", paint: gray.darken(40%))
+      )
+
       // Draw lifeline rectangles (reverse for bottom to top)
       for rect in rects.rev() {
         let (cx, y0, y1, style) = rect

src/sequence.typ

@@ -1,5 +1,6 @@
-#import "consts.typ": *
 #import "@preview/cetz:0.2.2": draw
+#import "consts.typ": *
+#import "participant.typ"
 
 #let _seq(
   p1,
@@ -36,15 +37,34 @@
   ),)
 }
 
-#let render(pars-i, x-pos, elmt, y, lifelines) = {
+#let render(pars-i, x-pos, participants, elmt, y, lifelines) = {
   let shapes = ()
 
+  // Reserve space for comment
+  if elmt.comment != none {
+    y -= measure(box(elmt.comment)).height / 1pt + 6
+  }
+
   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
-  }
+  let start-info = (
+    i: i1,
+    x: x-pos.at(i1),
+    y: y,
+    ll-lvl: lifelines.at(i1).level * LIFELINE-W / 2
+  )
+  let end-info = (
+    i: i2,
+    x: x-pos.at(i2),
+    y: y,
+    ll-lvl: lifelines.at(i2).level * LIFELINE-W / 2
+  )
+
+  let ll-lvl1 = lifelines.at(i1).level * LIFELINE-W / 2
+
+  let x1 = x-pos.at(i1)
+  let x2 = x-pos.at(i2)
 
   if elmt.disable-src {
     let src-line = lifelines.at(i1)
@@ -54,23 +74,18 @@
   }
   if elmt.destroy-src {
     let src-line = lifelines.at(i1)
-    src-line.level -= 1
-    src-line.lines.push(("destroy", y, auto))
+    src-line.lines.push(("destroy", y))
     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))
+    dst-line.lines.push(("disable", y))
     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))
+    dst-line.lines.push(("destroy", y))
     lifelines.at(i2) = dst-line
   }
   if elmt.enable-dst {
@@ -78,10 +93,14 @@
     dst-line.level += 1
     lifelines.at(i2) = dst-line
   }
+  if elmt.create-dst {
+    let par = participants.at(i2)
+    let m = measure(box(par.display-name))
+    x2 -= (m.width + PAR-PAD.last() * 2) / 2pt
+    shapes += participant.render(x-pos, par, y: y)
+  }
 
-  let x1 = x-pos.at(i1)
-  let x2 = x-pos.at(i2)
-
+  end-info.ll-lvl = lifelines.at(i2).level * LIFELINE-W / 2
   let ll-lvl2 = lifelines.at(i2).level * LIFELINE-W / 2
 
   let f = if elmt.flip {-1} else {1}