graph: create `WraparoundableIndex` enum for wraparoundables

src/draw.rs

@@ -6,6 +6,7 @@ use crate::{
     graph::{
         BendIndex, DotIndex, FixedDotIndex, FixedSegWeight, GetBand, GetNet, Index, LooseBendIndex,
         LooseBendWeight, LooseDotIndex, LooseDotWeight, LooseSegWeight, MakePrimitive,
+        WraparoundableIndex,
     },
     guide::Guide,
     layout::Layout,
@@ -139,12 +140,14 @@ impl<'a> Draw<'a> {
     pub fn segbend_around_dot(
         &mut self,
         head: Head,
-        around: DotIndex,
+        around: FixedDotIndex,
         width: f64,
     ) -> Result<SegbendHead, ()> {
-        let mut tangents = self
-            .guide(&Default::default())
-            .head_around_dot_segments(&head, around, width)?;
+        let mut tangents = self.guide(&Default::default()).head_around_dot_segments(
+            &head,
+            around.into(),
+            width,
+        )?;
         let mut dirs = [true, false];
 
         if tangents.1.euclidean_length() < tangents.0.euclidean_length() {
@@ -211,7 +214,7 @@ impl<'a> Draw<'a> {
     fn segbend_around(
         &mut self,
         head: Head,
-        around: Index,
+        around: WraparoundableIndex,
         from: Point,
         to: Point,
         cw: bool,
@@ -236,7 +239,7 @@ impl<'a> Draw<'a> {
     fn segbend(
         &mut self,
         head: Head,
-        around: Index,
+        around: WraparoundableIndex,
         to: Point,
         cw: bool,
         width: f64,

src/graph.rs

@@ -167,6 +167,23 @@ impl From<BendIndex> for Index {
     }
 }
 
+impl From<BendIndex> for WraparoundableIndex {
+    fn from(bend: BendIndex) -> Self {
+        match bend {
+            BendIndex::Fixed(bend) => WraparoundableIndex::FixedBend(bend),
+            BendIndex::Loose(bend) => WraparoundableIndex::LooseBend(bend),
+        }
+    }
+}
+
+#[enum_dispatch(GetNodeIndex, MakePrimitive, GetWraparound)]
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum WraparoundableIndex {
+    FixedBend(FixedBendIndex),
+    LooseBend(LooseBendIndex),
+    FixedDot(FixedDotIndex),
+}
+
 pub trait DotWeight: GetWidth + Into<Weight> + Copy {}
 
 #[derive(Debug, Clone, Copy, PartialEq)]

src/layout.rs

@@ -11,7 +11,7 @@ use crate::graph::{
     BendWeight, DotIndex, DotWeight, FixedBendIndex, FixedDotIndex, FixedDotWeight, FixedSegIndex,
     FixedSegWeight, GenericIndex, GetNodeIndex, Index, Interior, Label, LooseBendIndex,
     LooseBendWeight, LooseDotIndex, LooseDotWeight, LooseSegIndex, LooseSegWeight, MakePrimitive,
-    Retag, SegWeight, Weight,
+    Retag, SegWeight, Weight, WraparoundableIndex,
 };
 use crate::primitive::{GenericPrimitive, GetConnectable, GetWeight, MakeShape};
 use crate::segbend::Segbend;
@@ -123,7 +123,7 @@ impl Layout {
     pub fn add_segbend(
         &mut self,
         from: DotIndex,
-        around: Index,
+        around: WraparoundableIndex,
         dot_weight: LooseDotWeight,
         seg_weight: LooseSegWeight,
         bend_weight: LooseBendWeight,
@@ -215,13 +215,13 @@ impl Layout {
         &mut self,
         from: LooseDotIndex,
         to: LooseDotIndex,
-        around: Index,
+        around: WraparoundableIndex,
         weight: LooseBendWeight,
     ) -> Result<LooseBendIndex, ()> {
         match around {
-            Index::FixedDot(core) => self.add_core_bend(from, to, core, weight),
-            Index::FixedBend(around) => self.add_outer_bend(from, to, around, weight),
-            Index::LooseBend(around) => self.add_outer_bend(from, to, around, weight),
+            WraparoundableIndex::FixedDot(core) => self.add_core_bend(from, to, core, weight),
+            WraparoundableIndex::FixedBend(around) => self.add_outer_bend(from, to, around, weight),
+            WraparoundableIndex::LooseBend(around) => self.add_outer_bend(from, to, around, weight),
             _ => unreachable!(),
         }
     }