added groups

gallery/example1.typ

@@ -28,4 +28,18 @@ Alice <-- Bob: Another authentication Response
   import "/src/diagram.typ": *
   _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": *
+  _seq("Alice", "Bob", comment: "Authentication Request")
+  _seq("Bob", "Alice", comment: "Authentication Failure")
+
+  _grp("My own label", desc: "My own label2", {
+    _seq("Alice", "Log", comment: "Log attack start")
+    _grp("loop", desc: "1000 times", {
+      _seq("Alice", "Bob", comment: "DNS Attack")
+    })
+    _seq("Alice", "Bob", comment: "Log attack end")
+  })
 })

src/diagram.typ

@@ -1,3 +1,4 @@
+#import "utils.typ": get-group-span
 #import "renderer.typ": render
 
 #let _seq(
@@ -37,9 +38,40 @@
   return false
 }
 
+#let _grp(name, desc: none, type: "default", elmts) = {
+  return ((
+    type: "grp",
+    name: name,
+    desc: desc,
+    grp-type: type,
+    elmts: elmts
+  ),)
+}
+
 #let diagram(elements) = {
   let participants = ()
-  for elmt in elements {
+  let elmts = elements
+  let i = 0
+  let a = elmts.len()
+  while i < elmts.len() {
+    let elmt = elmts.at(i)
+    if elmt.type == "grp" {
+      elmts = (
+        elmts.slice(0, i + 1) +
+        elmt.elmts +
+        ((
+          type: "grp-end"
+        ),) +
+        elmts.slice(i+1)
+      )
+    }
+    i += 1
+  }
+  let b = elmts.len()
+  [#a / #b]
+  [#elmts.map(e => e.type)]
+
+  for elmt in elmts {
     if elmt.type == "par" {
       participants.push(elmt)
     } else if elmt.type == "seq" {
@@ -52,7 +84,15 @@
     }
   }
 
-  render(participants, elements)
+  for (i, elmt) in elmts.enumerate() {
+    if elmt.type == "grp" {
+      let (min-i, max-i) = get-group-span(participants, elmt)
+      elmts.at(i).insert("min-i", min-i)
+      elmts.at(i).insert("max-i", max-i)
+    }
+  }
+
+  render(participants, elmts)
 }
 
 #let from-plantuml(code) = {

src/renderer.typ

@@ -1,16 +1,10 @@
 #import "@preview/cetz:0.2.2": canvas, draw
+#import "utils.typ": get-participants-i
 
-#let Y-SPACE = 20
+#let Y-SPACE = 10
 #let PAR-PAD = (5pt, 3pt)
 #let PAR-SPACE = 10
 
-#let get-participants-i(participants) = {
-  let pars-i = (:)
-  for (i, p) in participants.enumerate() {
-    pars-i.insert(p.name, i)
-  }
-  return pars-i
-}
 
 #let get-columns-width(participants, elements) = {
   let pars-i = get-participants-i(participants)
@@ -62,6 +56,44 @@
   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 pars-i = get-participants-i(participants)
 
@@ -85,6 +117,8 @@
   }
 
   let y = -Y-SPACE
+  let groups = ()
+
   // Draw sequences
   for elmt in elements {
     if elmt.type == "seq" {
@@ -98,12 +132,8 @@
         )
       )
 
-      draw.line(
-        (x1, y),
-        (x2, y),
-        ..style
-      )
       if elmt.comment != none {
+        y -= measure(box(elmt.comment)).height / 1pt + 6
         draw.content(
           (calc.min(x1, x2), y),
           elmt.comment,
@@ -111,6 +141,33 @@
           padding: 3pt
         )
       }
+
+      draw.line(
+        (x1, y),
+        (x2, y),
+        ..style
+      )
+      y -= Y-SPACE
+    } else if elmt.type == "grp" {
+      let m = measure(
+        box(
+          inset: (left: 5pt, right: 5pt, top: 3pt, bottom: 3pt),
+        )
+      )
+      groups = groups.map(g => {
+        if g.at(1).min-i == elmt.min-i { g.at(2) += 1 }
+        if g.at(1).max-i == elmt.max-i { g.at(3) += 1 }
+        g
+      })
+      groups.push((y, elmt, 0, 0))
+      y -= m.height / 1pt + Y-SPACE
+    
+    } 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)
+
       y -= Y-SPACE
     }
   }

src/utils.typ

@@ -0,0 +1,27 @@
+#let get-participants-i(participants) = {
+  let pars-i = (:)
+  for (i, p) in participants.enumerate() {
+    pars-i.insert(p.name, i)
+  }
+  return pars-i
+}
+
+#let get-group-span(participants, group) = {
+  let min-i = participants.len() - 1
+  let max-i = 0
+  let pars-i = get-participants-i(participants)
+
+  for elmt in group.elmts {
+    if elmt.type == "seq" {
+      let i1 = pars-i.at(elmt.p1)
+      let i2 = pars-i.at(elmt.p2)
+      min-i = calc.min(min-i, i1, i2)
+      max-i = calc.max(max-i, i1, i2)
+    } else if elmt.type == "grp" {
+      let (i0, i1) = get-group-span(participants, elmt)
+      min-i = calc.min(min-i, i0)
+      max-i = calc.max(max-i, i1)
+    }
+  }
+  return (min-i, max-i)
+}