Add BoundingVerticesOfEdge query

crates/fj-core/src/queries.rs

@@ -8,3 +8,72 @@
 //!
 //! This module provides traits express such non-trivial queries, and implements
 //! them for various objects that have the information to answer the query.
+
+use crate::{
+    geometry::BoundingVertices,
+    objects::{Cycle, Face, HalfEdge, Region, Shell},
+    storage::Handle,
+};
+
+/// Determine the bounding vertices of an edge
+pub trait BoundingVerticesOfEdge {
+    /// Determine the bounding vertices of an edge
+    ///
+    /// Returns `None`, if the provided edge is not part of the object this
+    /// method is called on.
+    fn bounding_vertices_of_edge(
+        &self,
+        edge: &Handle<HalfEdge>,
+    ) -> Option<BoundingVertices>;
+}
+
+impl BoundingVerticesOfEdge for Cycle {
+    fn bounding_vertices_of_edge(
+        &self,
+        edge: &Handle<HalfEdge>,
+    ) -> Option<BoundingVertices> {
+        let start = edge.start_vertex().clone();
+        let end = self.half_edge_after(edge)?.start_vertex().clone();
+
+        Some(BoundingVertices::from([start, end]))
+    }
+}
+
+impl BoundingVerticesOfEdge for Region {
+    fn bounding_vertices_of_edge(
+        &self,
+        edge: &Handle<HalfEdge>,
+    ) -> Option<BoundingVertices> {
+        for cycle in self.all_cycles() {
+            if let Some(vertices) = cycle.bounding_vertices_of_edge(edge) {
+                return Some(vertices);
+            }
+        }
+
+        None
+    }
+}
+
+impl BoundingVerticesOfEdge for Face {
+    fn bounding_vertices_of_edge(
+        &self,
+        edge: &Handle<HalfEdge>,
+    ) -> Option<BoundingVertices> {
+        self.region().bounding_vertices_of_edge(edge)
+    }
+}
+
+impl BoundingVerticesOfEdge for Shell {
+    fn bounding_vertices_of_edge(
+        &self,
+        edge: &Handle<HalfEdge>,
+    ) -> Option<BoundingVertices> {
+        for face in self.faces() {
+            if let Some(vertices) = face.bounding_vertices_of_edge(edge) {
+                return Some(vertices);
+            }
+        }
+
+        None
+    }
+}