Some small improvements to iteration in graph and layout code

src/bow.rs

@@ -1,6 +1,6 @@
 use petgraph::stable_graph::StableDiGraph;
 
-use crate::graph::{BendIndex, DotIndex, Label, Path, SegIndex, TaggedIndex, TaggedWeight};
+use crate::graph::{BendIndex, DotIndex, Label, SegIndex, TaggedIndex, TaggedWeight, Walk};
 use crate::primitive::{Bend, Dot, Seg};
 
 pub struct Bow<'a> {
@@ -18,13 +18,21 @@ impl<'a> Bow<'a> {
     pub fn new(index: BendIndex, graph: &'a StableDiGraph<TaggedWeight, Label, usize>) -> Self {
         let bend = index;
 
-        let seg1_dot2 = *Bend::new(bend, graph).prev().unwrap().as_dot().unwrap();
-        let seg1 = *Dot::new(seg1_dot2, graph).prev().unwrap().as_seg().unwrap();
-        let seg1_dot1 = *Seg::new(seg1, graph).prev().unwrap().as_dot().unwrap();
+        let seg1_dot2 = Bend::new(bend, graph).prev().unwrap();
+        let seg1 = *Dot::new(seg1_dot2, graph)
+            .tagged_prev()
+            .unwrap()
+            .as_seg()
+            .unwrap();
+        let seg1_dot1 = Seg::new(seg1, graph).prev().unwrap();
 
-        let seg2_dot1 = *Bend::new(bend, graph).next().unwrap().as_dot().unwrap();
-        let seg2 = *Dot::new(seg2_dot1, graph).next().unwrap().as_seg().unwrap();
-        let seg2_dot2 = *Seg::new(seg2, graph).next().unwrap().as_dot().unwrap();
+        let seg2_dot1 = Bend::new(bend, graph).next().unwrap();
+        let seg2 = *Dot::new(seg2_dot1, graph)
+            .tagged_next()
+            .unwrap()
+            .as_seg()
+            .unwrap();
+        let seg2_dot2 = Seg::new(seg2, graph).next().unwrap();
 
         Self {
             seg1_dot1,
@@ -39,7 +47,7 @@ impl<'a> Bow<'a> {
     }
 }
 
-impl<'a> Path for Bow<'a> {
+impl<'a> Walk for Bow<'a> {
     fn interior(&self) -> Vec<TaggedIndex> {
         vec![
             TaggedIndex::Seg(self.seg1),

src/graph.rs

@@ -4,7 +4,7 @@ use std::marker::PhantomData;
 
 use crate::math::Circle;
 
-pub trait Path {
+pub trait Walk {
     fn interior(&self) -> Vec<TaggedIndex>;
     fn closure(&self) -> Vec<TaggedIndex>;
     fn ends(&self) -> [DotIndex; 2];

src/layout.rs

@@ -8,8 +8,8 @@ use spade::{DelaunayTriangulation, HasPosition, Point2, Triangulation};
 
 use crate::bow::Bow;
 use crate::graph::{
-    BendIndex, BendWeight, DotIndex, DotWeight, Index, Label, Path, SegIndex, SegWeight, Tag,
-    TaggedIndex, TaggedWeight,
+    BendIndex, BendWeight, DotIndex, DotWeight, Index, Label, SegIndex, SegWeight, Tag,
+    TaggedIndex, TaggedWeight, Walk,
 };
 use crate::primitive::Primitive;
 use crate::shape::Shape;
@@ -261,8 +261,7 @@ impl Layout {
     }
 
     pub fn dots(&self) -> impl Iterator<Item = DotIndex> + '_ {
-        self.nodes()
-            .filter_map(|ni| ni.as_dot().and_then(|di| Some(*di)))
+        self.nodes().filter_map(|ni| ni.as_dot().map(|di| *di))
     }
 
     pub fn shapes(&self) -> impl Iterator<Item = Shape> + '_ {

src/primitive.rs

@@ -1,11 +1,11 @@
 use std::mem::{self, swap};
 
-use petgraph::stable_graph::StableDiGraph;
+use petgraph::stable_graph::{NodeIndex, StableDiGraph};
 use petgraph::Direction::{Incoming, Outgoing};
 
 use crate::graph::{
-    BendIndex, BendWeight, DotIndex, DotWeight, Index, Label, Path, SegIndex, SegWeight, Tag,
-    TaggedIndex, TaggedWeight,
+    BendIndex, BendWeight, DotIndex, DotWeight, Index, Label, SegIndex, SegWeight, Tag,
+    TaggedIndex, TaggedWeight, Walk,
 };
 use crate::math::{self, Circle};
 use crate::shape::{BendShape, DotShape, SegShape, Shape};
@@ -80,20 +80,7 @@ impl<'a, Weight> Primitive<'a, Weight> {
             .map(|index| Index::<Label>::new(index).retag(self.graph.node_weight(index).unwrap()))
     }
 
-    pub fn next(&self) -> Option<TaggedIndex> {
-        self.graph
-            .neighbors_directed(self.index.index, Outgoing)
-            .filter(|ni| {
-                self.graph
-                    .edge_weight(self.graph.find_edge(self.index.index, *ni).unwrap())
-                    .unwrap()
-                    .is_end()
-            })
-            .map(|ni| Index::<Label>::new(ni).retag(self.graph.node_weight(ni).unwrap()))
-            .next()
-    }
-
-    pub fn next_akin(&self) -> Option<Index<Weight>> {
+    pub fn find_next_akin(&self) -> Option<Index<Weight>> {
         let mut prev_index = self.index.index;
 
         while let Some(index) = self
@@ -120,20 +107,24 @@ impl<'a, Weight> Primitive<'a, Weight> {
         None
     }
 
-    pub fn prev(&self) -> Option<TaggedIndex> {
+    pub fn tagged_next(&self) -> Option<TaggedIndex> {
+        self.next_node()
+            .map(|ni| Index::<Label>::new(ni).retag(self.graph.node_weight(ni).unwrap()))
+    }
+
+    fn next_node(&self) -> Option<NodeIndex<usize>> {
         self.graph
-            .neighbors_directed(self.index.index, Incoming)
+            .neighbors_directed(self.index.index, Outgoing)
             .filter(|ni| {
                 self.graph
-                    .edge_weight(self.graph.find_edge(*ni, self.index.index).unwrap())
+                    .edge_weight(self.graph.find_edge(self.index.index, *ni).unwrap())
                     .unwrap()
                     .is_end()
             })
-            .map(|ni| Index::<Label>::new(ni).retag(self.graph.node_weight(ni).unwrap()))
             .next()
     }
 
-    pub fn prev_akin(&self) -> Option<Index<Weight>> {
+    pub fn find_prev_akin(&self) -> Option<Index<Weight>> {
         let mut prev_index = self.index.index;
 
         while let Some(index) = self
@@ -160,6 +151,23 @@ impl<'a, Weight> Primitive<'a, Weight> {
         None
     }
 
+    pub fn tagged_prev(&self) -> Option<TaggedIndex> {
+        self.prev_node()
+            .map(|ni| Index::<Label>::new(ni).retag(self.graph.node_weight(ni).unwrap()))
+    }
+
+    fn prev_node(&self) -> Option<NodeIndex<usize>> {
+        self.graph
+            .neighbors_directed(self.index.index, Incoming)
+            .filter(|ni| {
+                self.graph
+                    .edge_weight(self.graph.find_edge(*ni, self.index.index).unwrap())
+                    .unwrap()
+                    .is_end()
+            })
+            .next()
+    }
+
     pub fn core(&self) -> Option<DotIndex> {
         self.graph
             .neighbors(self.index.index)
@@ -208,7 +216,7 @@ impl<'a, Weight> Primitive<'a, Weight> {
     }
 }
 
-impl<'a, Weight> Path for Primitive<'a, Weight> {
+impl<'a, Weight> Walk for Primitive<'a, Weight> {
     fn interior(&self) -> Vec<TaggedIndex> {
         vec![self.tagged_index()]
     }
@@ -288,6 +296,14 @@ impl<'a> Dot<'a> {
 }
 
 impl<'a> Seg<'a> {
+    pub fn next(&self) -> Option<DotIndex> {
+        self.next_node().map(|ni| DotIndex::new(ni))
+    }
+
+    pub fn prev(&self) -> Option<DotIndex> {
+        self.prev_node().map(|ni| DotIndex::new(ni))
+    }
+
     pub fn weight(&self) -> SegWeight {
         *self.tagged_weight().as_seg().unwrap()
     }
@@ -328,6 +344,14 @@ impl<'a> Bend<'a> {
             .next()
     }
 
+    pub fn next(&self) -> Option<DotIndex> {
+        self.next_node().map(|ni| DotIndex::new(ni))
+    }
+
+    pub fn prev(&self) -> Option<DotIndex> {
+        self.prev_node().map(|ni| DotIndex::new(ni))
+    }
+
     pub fn weight(&self) -> BendWeight {
         *self.tagged_weight().as_bend().unwrap()
     }

src/router.rs

@@ -307,7 +307,7 @@ impl Router {
 
     fn relax_band(&mut self, bend: BendIndex) {
         let mut prev_bend = bend;
-        while let Some(cur_bend) = self.layout.primitive(prev_bend).prev_akin() {
+        while let Some(cur_bend) = self.layout.primitive(prev_bend).find_prev_akin() {
             if self.layout.primitive(cur_bend).cross_product() >= 0. {
                 self.release_bow(cur_bend);
             }
@@ -316,7 +316,7 @@ impl Router {
         }
 
         let mut prev_bend = bend;
-        while let Some(cur_bend) = self.layout.primitive(prev_bend).next_akin() {
+        while let Some(cur_bend) = self.layout.primitive(prev_bend).find_next_akin() {
             if self.layout.primitive(cur_bend).cross_product() >= 0. {
                 self.release_bow(cur_bend);
             }