drawing: move head length measurement methods to new refstruct

src/drawing/drawing.rs

@@ -35,6 +35,8 @@ use crate::geometry::{
 use crate::graph::{GenericIndex, GetPetgraphIndex};
 use crate::math::NoTangents;
 
+use super::head::{Head, HeadRef};
+
 #[enum_dispatch]
 #[derive(Error, Debug, Clone, Copy)]
 pub enum LayoutException {
@@ -919,6 +921,10 @@ impl<CW: Copy, R: RulesTrait> Drawing<CW, R> {
         Loose::new(index, self)
     }
 
+    pub fn head_ref(&self, head: Head) -> HeadRef<'_, CW, R> {
+        HeadRef::new(head, self)
+    }
+
     pub fn layer_count(&self) -> usize {
         self.geometry_with_rtree.layer_count()
     }

src/drawing/guide.rs

@@ -1,15 +1,6 @@
-use enum_dispatch::enum_dispatch;
 use geo::Line;
 
 use crate::{
-    drawing::{
-        bend::BendIndex,
-        dot::{DotIndex, FixedDotIndex, LooseDotIndex},
-        graph::MakePrimitive,
-        primitive::{GetCore, GetInnerOuter, GetOtherJoint, GetWeight, MakePrimitiveShape},
-        rules::GetConditions,
-        Drawing,
-    },
     geometry::{
         primitive::{PrimitiveShape, PrimitiveShapeTrait},
         shape::ShapeTrait,
@@ -18,47 +9,15 @@ use crate::{
 };
 
 use super::{
-    cane::Cane,
-    graph::PrimitiveIndex,
-    primitive::GetJoints,
-    rules::{Conditions, RulesTrait},
+    bend::BendIndex,
+    dot::{DotIndex, FixedDotIndex, LooseDotIndex},
+    graph::{MakePrimitive, PrimitiveIndex},
+    head::{BareHead, CaneHead, Head, HeadTrait},
+    primitive::{GetCore, GetInnerOuter, GetJoints, GetOtherJoint, GetWeight, MakePrimitiveShape},
+    rules::{Conditions, GetConditions, RulesTrait},
+    Drawing,
 };
 
-#[enum_dispatch]
-pub trait HeadTrait {
-    fn face(&self) -> DotIndex;
-}
-
-#[enum_dispatch(HeadTrait)]
-#[derive(Debug, Clone, Copy)]
-pub enum Head {
-    Bare(BareHead),
-    Cane(CaneHead),
-}
-
-#[derive(Debug, Clone, Copy)]
-pub struct BareHead {
-    pub face: FixedDotIndex,
-}
-
-impl HeadTrait for BareHead {
-    fn face(&self) -> DotIndex {
-        self.face.into()
-    }
-}
-
-#[derive(Debug, Clone, Copy)]
-pub struct CaneHead {
-    pub face: LooseDotIndex,
-    pub cane: Cane,
-}
-
-impl HeadTrait for CaneHead {
-    fn face(&self) -> DotIndex {
-        self.face.into()
-    }
-}
-
 pub struct Guide<'a, CW: Copy, R: RulesTrait> {
     drawing: &'a Drawing<CW, R>,
 }

src/drawing/head.rs

@@ -0,0 +1,84 @@
+use enum_dispatch::enum_dispatch;
+
+use crate::geometry::shape::MeasureLength;
+
+use super::{
+    cane::Cane,
+    dot::{DotIndex, FixedDotIndex, LooseDotIndex},
+    primitive::MakePrimitiveShape,
+    rules::RulesTrait,
+    Drawing,
+};
+
+#[enum_dispatch]
+pub trait HeadTrait {
+    fn face(&self) -> DotIndex;
+}
+
+#[enum_dispatch(HeadTrait)]
+#[derive(Debug, Clone, Copy)]
+pub enum Head {
+    Bare(BareHead),
+    Cane(CaneHead),
+}
+
+impl Head {
+    pub fn ref_<'a, CW: Copy, R: RulesTrait>(
+        &self,
+        drawing: &'a Drawing<CW, R>,
+    ) -> HeadRef<'a, CW, R> {
+        HeadRef::new(*self, drawing)
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct BareHead {
+    pub face: FixedDotIndex,
+}
+
+impl HeadTrait for BareHead {
+    fn face(&self) -> DotIndex {
+        self.face.into()
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct CaneHead {
+    pub face: LooseDotIndex,
+    pub cane: Cane,
+}
+
+impl HeadTrait for CaneHead {
+    fn face(&self) -> DotIndex {
+        self.face.into()
+    }
+}
+
+pub struct HeadRef<'a, CW: Copy, R: RulesTrait> {
+    head: Head,
+    drawing: &'a Drawing<CW, R>,
+}
+
+impl<'a, CW: Copy, R: RulesTrait> HeadRef<'a, CW, R> {
+    pub fn new(head: Head, drawing: &'a Drawing<CW, R>) -> Self {
+        Self { drawing, head }
+    }
+}
+
+impl<'a, CW: Copy, R: RulesTrait> HeadTrait for HeadRef<'a, CW, R> {
+    fn face(&self) -> DotIndex {
+        self.head.face()
+    }
+}
+
+impl<'a, CW: Copy, R: RulesTrait> MeasureLength for HeadRef<'a, CW, R> {
+    fn length(&self) -> f64 {
+        match self.head {
+            Head::Bare(..) => 0.0,
+            Head::Cane(cane_head) => {
+                self.drawing.primitive(cane_head.cane.seg).shape().length()
+                    + self.drawing.primitive(cane_head.cane.bend).shape().length()
+            }
+        }
+    }
+}

src/drawing/mod.rs

@@ -7,6 +7,7 @@ pub mod collect;
 pub mod dot;
 mod drawing;
 pub mod guide;
+pub mod head;
 pub mod loose;
 pub mod primitive;
 pub mod rules;

src/router/draw.rs

@@ -8,7 +8,8 @@ use crate::{
         bend::{BendIndex, LooseBendWeight},
         dot::{DotIndex, FixedDotIndex, LooseDotIndex, LooseDotWeight},
         graph::{GetLayer, GetMaybeNet, MakePrimitive},
-        guide::{CaneHead, Guide, Head, HeadTrait},
+        guide::Guide,
+        head::{CaneHead, Head, HeadTrait},
         primitive::GetOtherJoint,
         rules::RulesTrait,
         seg::{LoneLooseSegWeight, SeqLooseSegWeight},

src/router/route.rs

@@ -11,7 +11,6 @@ use crate::{
         band::BandFirstSegIndex,
         dot::{DotIndex, FixedDotIndex},
         graph::{MakePrimitive, PrimitiveIndex},
-        guide::{CaneHead, Head, HeadTrait},
         primitive::MakePrimitiveShape,
         rules::RulesTrait,
     },

src/router/router.rs

@@ -7,7 +7,7 @@ use crate::{
         band::BandFirstSegIndex,
         dot::{DotIndex, FixedDotIndex},
         graph::{MakePrimitive, PrimitiveIndex},
-        guide::{Head, HeadTrait},
+        head::{Head, HeadTrait},
         primitive::MakePrimitiveShape,
         rules::RulesTrait,
     },
@@ -56,33 +56,17 @@ impl<'a, R: RulesTrait> RouterAstarStrategy<'a, R> {
     }
 
     fn bihead_length(&self) -> f64 {
-        self.head_length(&self.trace.head)
+        self.trace.head.ref_(self.tracer.layout.drawing()).length()
             + match self.trace.head.face() {
                 DotIndex::Fixed(..) => 0.0,
-                DotIndex::Loose(face) => {
-                    self.head_length(&self.tracer.layout.drawing().guide().rear_head(face))
-                }
-            }
-    }
-
-    fn head_length(&self, head: &Head) -> f64 {
-        match head {
-            Head::Bare(..) => 0.0,
-            Head::Cane(cane_head) => {
-                self.tracer
-                    .layout
-                    .drawing()
-                    .primitive(cane_head.cane.seg)
-                    .shape()
-                    .length()
-                    + self
+                DotIndex::Loose(face) => self
                     .tracer
                     .layout
                     .drawing()
-                        .primitive(cane_head.cane.bend)
-                        .shape()
-                        .length()
-            }
+                    .guide()
+                    .rear_head(face)
+                    .ref_(self.tracer.layout.drawing())
+                    .length(),
             }
     }
 }

src/router/trace.rs

@@ -6,7 +6,7 @@ use crate::{
         bend::LooseBendIndex,
         dot::FixedDotIndex,
         graph::PrimitiveIndex,
-        guide::{BareHead, CaneHead, Head},
+        head::{BareHead, CaneHead, Head},
         rules::RulesTrait,
     },
     router::{

src/router/tracer.rs

@@ -7,11 +7,7 @@ use thiserror::Error;
 
 use crate::{
     drawing::{
-        band::BandFirstSegIndex,
-        bend::LooseBendIndex,
-        dot::FixedDotIndex,
-        graph::PrimitiveIndex,
-        guide::{BareHead, CaneHead, Head},
+        band::BandFirstSegIndex, bend::LooseBendIndex, dot::FixedDotIndex, graph::PrimitiveIndex,
         rules::RulesTrait,
     },
     layout::Layout,