Support per-view connection boundary attachments in ordinary and state diagrams

crates/oa-desktop/src/route_edit.rs

@@ -14,6 +14,9 @@ pub struct Context {
 pub enum Event {
     SelectBend(Id, usize),
     Commit(Context, EdgeRoute, Option<usize>),
+    CommitAttachment(Context, EdgeRoute, EdgeEnd, Id),
+    ChooseAttachment(EdgeEnd),
+    ResetAttachment(EdgeEnd),
     AddBend,
     AddBendAt(oa_core::Position),
     RemoveBend,
@@ -23,7 +26,14 @@ pub enum Event {
 #[derive(Debug, Clone)]
 pub enum Handle {
     Bend(usize),
-    Label { original: Position },
+    Label {
+        original: Position,
+    },
+    Attachment {
+        end: EdgeEnd,
+        owner: projection::ProjectedNode,
+        original: Option<EdgeAttachment>,
+    },
 }
 
 #[derive(Debug, Clone)]
@@ -58,8 +68,57 @@ impl Gesture {
                     };
                 }
             }
+            Handle::Attachment { .. } => {}
         }
     }
+
+    pub fn move_attachment_to(&mut self, point: Point, zoom: f32) {
+        let Handle::Attachment {
+            end,
+            ref owner,
+            original,
+        } = self.handle
+        else {
+            self.move_to(point, zoom);
+            return;
+        };
+        if point.distance(self.start) * zoom < 3. {
+            self.route.set_attachment(end, original);
+            self.changed = false;
+            return;
+        }
+        self.changed = true;
+        let attachment = attachment_from_point(
+            owner,
+            position(point),
+            self.route.attachment(end).map(|a| a.side),
+            6. / zoom,
+        );
+        self.route.set_attachment(end, Some(attachment));
+    }
+}
+
+/// The painted endpoint must still be the actual unported placement, not a folded proxy.
+pub fn attachment_node<'a>(
+    project: &Project,
+    diagram: &Diagram,
+    view: &'a projection::ProjectedView,
+    edge: Id,
+    end: EdgeEnd,
+) -> Option<&'a projection::ProjectedNode> {
+    if semantic_port_endpoint(project, edge, end).is_some() {
+        return None;
+    }
+    let projected = view.edges.iter().find(|e| e.id == edge)?;
+    let actual = projection::edge_endpoint_placements(project, diagram, edge)?;
+    if actual != (projected.source, projected.target) {
+        return None;
+    }
+    let placement = match end {
+        EdgeEnd::Source => projected.source,
+        EdgeEnd::Target => projected.target,
+    };
+    view.nodes.iter().find(|node| node.id == placement)
 }
 
 pub fn stored_route(diagram: &Diagram, edge: Id) -> EdgeRoute {
@@ -72,6 +131,8 @@ pub fn stored_route(diagram: &Diagram, edge: Id) -> EdgeRoute {
             edge,
             waypoints: Vec::new(),
             label: None,
+            source_attachment: None,
+            target_attachment: None,
         })
 }