Implements FixedVertexHandle::from_index

src/delaunay_core/handles/handle_defs.rs

@@ -2,6 +2,7 @@ use core::convert::TryInto;
 
 use super::super::Dcel;
 use super::public_handles::{InnerOuterMarker, PossiblyOuterTag};
+use super::FixedVertexHandle;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
@@ -43,6 +44,23 @@ pub const fn new_fixed_face_handle(index: usize) -> FixedHandleImpl<FaceTag, Pos
     }
 }
 
+impl FixedVertexHandle {
+    /// Creates a new vertex handle from a `usize`.
+    ///
+    /// Ideally, this method should only be used in advanced scenarios as it allows to create
+    /// invalid vertex handles. When possible, attempt to retrieve handles by other means
+    /// instead (see [crate::handles]).
+    ///
+    /// # Panics
+    ///
+    /// Panics if `index >= 2^32`
+    pub fn from_index(index: usize) -> Self {
+        // Preferably, `new` would simply be public. However, that would allow to create a handle
+        // to the outer face marked with `InnerTag` which is bad. Let's only allow vertices for now.
+        Self::new(index)
+    }
+}
+
 impl<Type: Default, InnerOuter: InnerOuterMarker> FixedHandleImpl<Type, InnerOuter> {
     pub(crate) fn new(index: usize) -> Self {
         Self::new_internal(

src/lib.rs

@@ -114,6 +114,12 @@ mod test_utilities;
 /// | **Reference**  | [vertices()](Triangulation::vertices()) | [directed_edges()](Triangulation::directed_edges) | [undirected_edges()](Triangulation::undirected_edges()) | [inner_faces()](Triangulation::inner_faces())<br>[all_faces()](Triangulation::all_faces()) |
 /// | **Fixed**      | [fixed_vertices()](Triangulation::fixed_vertices()) | [fixed_directed_edges()](Triangulation::fixed_directed_edges()) | [fixed_undirected_edges()](Triangulation::fixed_undirected_edges()) | [fixed_inner_faces()](Triangulation::fixed_inner_faces())<br> [fixed_faces()](Triangulation::fixed_inner_faces()) |
 ///
+/// # Creating handles directly
+///
+/// In some cases it may be desireable to create vertex handles artificially by providing the index
+/// manually. This can be done by calling [handles::FixedVertexHandle::from_index](from_index(usize)).
+/// Make sure that the provided index is smaller than the number of vertices in the triangulation.
+///
 /// # Converting between reference and fixed handles
 ///
 /// Converting a reference handle into its fixed counterpart is performed via the