added show-top / -bottom options to participants

gallery/example3.typ

@@ -134,3 +134,14 @@ chronos.diagram({
   _seq("a", "a", start-tip: "x", end-tip: ("o", ">"), comment: `x->o`)
 })
 )
+
+#chronos.diagram({
+  import chronos: *
+
+  _par("a", display-name: "Alice")
+  _par("b", display-name: "Bob", show-bottom: false)
+  _par("c", display-name: "Caleb", show-top: false)
+  _par("d", display-name: "Danny", show-bottom: false, show-top: false)
+
+  _gap()
+})

src/participant.typ

@@ -21,7 +21,9 @@
   invisible: false,
   shape: "participant",
   color: rgb("#E2E2F0"),
-  custom-image: none
+  custom-image: none,
+  show-bottom: true,
+  show-top: true,
 ) = {
   return ((
     type: "par",
@@ -31,7 +33,9 @@
     invisible: invisible,
     shape: shape,
     color: color,
-    custom-image: custom-image
+    custom-image: custom-image,
+    show-bottom: show-bottom,
+    show-top: show-top
   ),)
 }
 

src/renderer.typ

@@ -218,7 +218,7 @@
   
   // Draw participants (start)
   for p in participants {
-    if p.from-start and not p.invisible {
+    if p.from-start and not p.invisible and p.show-top {
       shapes += draw-par(p)
     }
   }
@@ -417,8 +417,10 @@
       }
 
       // Draw participants (end)
+      if p.show-bottom {
         draw-par(p, y: y, bottom: true)
       }
+    }
   })
 
   shapes