Enable direct and menu bend editing in State diagrams

crates/oa-desktop/src/route_edit.rs

@@ -137,6 +137,34 @@ pub fn stored_route(diagram: &Diagram, edge: Id) -> EdgeRoute {
 }
 
 /// Insert after the pins preceding the clicked segment along the routed path.
+pub fn insert_pin_on_segment(
+    route: &mut EdgeRoute,
+    geometry: &RoutedEdge,
+    segment: usize,
+    point: Position,
+) -> Option<usize> {
+    if route.edge != geometry.id
+        || geometry.custom_suspended
+        || route.waypoints != geometry.pins
+        || route.waypoints.len() >= 128
+        || !point.x.is_finite()
+        || !point.y.is_finite()
+        || geometry
+            .points
+            .get(segment..segment.checked_add(2)?)
+            .is_none()
+    {
+        return None;
+    }
+    let index = pin_insertion_index(geometry, segment, point);
+    if index > route.waypoints.len() {
+        return None;
+    }
+    route.waypoints.insert(index, point);
+    Some(index)
+}
+
+/// Find a segment when an ordinary caller has only a point, not a captured hit.
 pub fn insert_pin(route: &mut EdgeRoute, geometry: &RoutedEdge, point: Position) -> usize {
     let segment = geometry
         .points