Add methods to obtain pin and component attractions

topola/src/board/mod.rs

@@ -22,7 +22,7 @@ use undoredo::{Delta, Recorder};
 use crate::{
     layout::{
         LayerId, Layout, LayoutHalfDelta,
-        compounds::{ComponentId, NetId, PinId},
+        compounds::{ComponentId, NetId, PinId, PinSpec},
     },
     vector::Vector2,
 };
@@ -43,7 +43,11 @@ pub struct Board {
 impl Board {
     /*pub fn new(boundary: Vec<Vector2<i64>>, layer_count: usize) -> Self {
         Self {
-            layout: Layout::new(boundary.into_iter().map(Into::into).collect(), layer_count),
+            layout: Layout::new(
+                boundary.into_iter().map(Into::into).collect(),
+                layer_count,
+                0,
+            ),
             component_names: Recorder::new(BiBTreeMap::new()),
             pin_names: Recorder::new(BiBTreeMap::new()),
             layer_descs: Recorder::new(BiBTreeMap::new()),
@@ -60,6 +64,7 @@ impl Board {
             layout: Layout::new(
                 boundary.into_iter().map(Into::into).collect(),
                 layer_descs.len(),
+                net_names.len(),
             ),
             component_names: Recorder::new(BiBTreeMap::new()),
             pin_names: Recorder::new(BiBTreeMap::new()),
@@ -79,12 +84,12 @@ impl Board {
         component_id
     }
 
-    pub fn ensure_named_pin(&mut self, pin_name: String, net_id: Option<NetId>) -> PinId {
+    pub fn ensure_named_pin(&mut self, pin_name: String, pin_spec: PinSpec) -> PinId {
         if let Some(pin) = self.pin_names.get_by_right(&pin_name) {
             return *pin;
         };
 
-        let pin_id = self.layout.insert_pin(net_id);
+        let pin_id = self.layout.insert_pin(pin_spec);
         self.pin_names.insert(pin_id, pin_name);
 
         pin_id

topola/src/layout/attraction.rs

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2026 Topola contributors
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use crate::{
+    Layout, Vector2,
+    layout::compounds::{ComponentId, PinId},
+};
+
+impl Layout {
+    pub fn component_attractions(
+        &self,
+        attractee: ComponentId,
+    ) -> impl Iterator<Item = Vector2<i64>> + '_ {
+        self.component(attractee)
+            .pins
+            .iter()
+            .flat_map(move |&pin_id| self.pin_attractions(pin_id))
+    }
+
+    pub fn pin_attractions(&self, attractee: PinId) -> impl Iterator<Item = Vector2<i64>> + '_ {
+        self.pin(attractee)
+            .spec
+            .net
+            .into_iter()
+            .flat_map(move |net_id| {
+                self.nets[net_id.index()]
+                    .pins
+                    .iter()
+                    .copied()
+                    .filter(move |&attractor| attractor != attractee)
+                    .map(move |attractor| self.pin_pin_attraction(attractee, attractor))
+            })
+    }
+
+    pub fn pin_pin_attraction(&self, attractee: PinId, attractor: PinId) -> Vector2<i64> {
+        self.pin_centroid(attractor) - self.pin_centroid(attractee)
+    }
+}

topola/src/layout/compounds/component.rs

@@ -6,6 +6,7 @@ use derive_more::{Constructor, From};
 use serde::{Deserialize, Serialize};
 
 use crate::{
+    PinId,
     layout::primitives::{JointId, PolygonId, SegmentId, ViaId},
     primitives::PrimitiveId,
 };
@@ -35,6 +36,7 @@ impl ComponentId {
 
 #[derive(Clone, Debug, Default)]
 pub struct Component {
+    pub pins: Vec<PinId>,
     pub joints: Vec<JointId>,
     pub segments: Vec<SegmentId>,
     pub vias: Vec<ViaId>,

topola/src/layout/compounds/pin.rs

@@ -5,7 +5,13 @@
 use derive_more::{Constructor, From};
 use serde::{Deserialize, Serialize};
 
-use crate::layout::primitives::{JointId, PolygonId, SegmentId, ViaId};
+use crate::{
+    Layout, Vector2,
+    layout::{
+        compounds::{ComponentId, NetId},
+        primitives::{JointId, PolygonId, SegmentId, ViaId},
+    },
+};
 
 #[derive(
     Clone,
@@ -30,8 +36,15 @@ impl PinId {
     }
 }
 
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Copy, Debug)]
+pub struct PinSpec {
+    pub component: Option<ComponentId>,
+    pub net: Option<NetId>,
+}
+
+#[derive(Clone, Debug)]
 pub struct Pin {
+    pub spec: PinSpec,
     pub joints: Vec<JointId>,
     pub segments: Vec<SegmentId>,
     pub vias: Vec<ViaId>,
@@ -39,7 +52,45 @@ pub struct Pin {
 }
 
 impl Pin {
-    pub fn new() -> Self {
-        Default::default()
+    pub fn new(spec: PinSpec) -> Self {
+        Pin {
+            spec,
+            joints: Vec::new(),
+            segments: Vec::new(),
+            vias: Vec::new(),
+            polygons: Vec::new(),
+        }
+    }
+}
+
+impl Layout {
+    pub fn pin_centroid(&self, pin_id: PinId) -> Vector2<i64> {
+        let pin = self.pin(pin_id);
+        let mut sum = Vector2::new(0, 0);
+        let mut count = 0;
+
+        for &joint_id in &pin.joints {
+            sum = sum + self.joint(joint_id).center();
+            count += 1;
+        }
+        for &segment_id in &pin.segments {
+            sum = sum + self.segment(segment_id).center();
+            count += 1;
+        }
+        for &via_id in &pin.vias {
+            sum = sum + self.via(via_id).position;
+            count += 1;
+        }
+        for &polygon_id in &pin.polygons {
+            sum = sum + self.polygon(polygon_id).center();
+            count += 1;
+        }
+
+        if count == 0 {
+            return Vector2::new(0, 0);
+        }
+
+        let count = count as i64;
+        Vector2::new(sum.x / count, sum.y / count)
     }
 }

topola/src/layout/infringement.rs

@@ -392,7 +392,7 @@ impl Layout {
         }
     }
 
-    fn primitive_net(&self, primitive: PrimitiveId) -> Option<NetId> {
+    pub fn primitive_net(&self, primitive: PrimitiveId) -> Option<NetId> {
         match primitive {
             PrimitiveId::Joint(joint_id) => self.joint(joint_id).spec.net,
             PrimitiveId::Segment(segment_id) => self.segment(segment_id).net,

topola/src/layout/insert.rs

@@ -5,10 +5,9 @@
 use rstar::primitives::GeomWithData;
 
 use crate::{
-    Pin, PinId,
     layout::{
         Layout,
-        compounds::{Component, ComponentId, NetId},
+        compounds::{Component, ComponentId, Pin, PinId, PinSpec},
     },
     primitives::{
         Joint, JointId, JointSpec, Polygon, PolygonId, Segment, SegmentId, SegmentSpec, Via, ViaId,
@@ -21,10 +20,16 @@ impl Layout {
         ComponentId::new(self.components.push(Component::new()))
     }
 
-    pub fn insert_pin(&mut self, net_id: Option<NetId>) -> PinId {
-        let pin_id = PinId::new(self.pins.push(Pin::new()));
+    pub fn insert_pin(&mut self, spec: PinSpec) -> PinId {
+        let pin_id = PinId::new(self.pins.push(Pin::new(spec)));
 
-        if let Some(net_id) = net_id {
+        if let Some(component_id) = spec.component {
+            self.components.modify(component_id.index(), |component| {
+                component.pins.push(pin_id)
+            });
+        }
+
+        if let Some(net_id) = spec.net {
             self.nets
                 .modify(net_id.index(), |net| net.pins.push(pin_id));
         }
@@ -33,11 +38,7 @@ impl Layout {
     }
 
     pub fn insert_joint(&mut self, spec: JointSpec) -> JointId {
-        let joint = Joint {
-            spec,
-            segments: Vec::new(),
-            vias: Vec::new(),
-        };
+        let joint = Joint::new(spec);
         let bbox = joint.bbox();
         let component_id = joint.spec.component;
         let pin_id = joint.spec.pin;

topola/src/layout/mod.rs

@@ -2,6 +2,7 @@
 //
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
+mod attraction;
 mod bbox;
 pub mod compounds;
 mod delete;
@@ -90,14 +91,19 @@ pub struct Layout {
 }
 
 impl Layout {
-    pub fn new(boundary: Vec<[i64; 2]>, layer_count: usize) -> Self {
+    pub fn new(boundary: Vec<[i64; 2]>, layer_count: usize, net_count: usize) -> Self {
+        let mut nets = StableVec::new();
+        for _ in 0..net_count {
+            nets.push(Net::default());
+        }
+
         Self {
             boundary: boundary.clone(),
             place_boundary: boundary,
             layer_count,
 
             components: Recorder::new(StableVec::new()),
-            nets: Recorder::new(StableVec::new()),
+            nets: Recorder::new(nets),
             pins: Recorder::new(StableVec::new()),
 
             joints: Recorder::new(StableVec::new()),

topola/src/layout/primitives/joint.rs

@@ -52,6 +52,14 @@ pub struct Joint {
 }
 
 impl Joint {
+    pub fn new(spec: JointSpec) -> Self {
+        Joint {
+            spec,
+            segments: Vec::new(),
+            vias: Vec::new(),
+        }
+    }
+
     pub fn center(&self) -> Vector2<i64> {
         self.spec.position
     }

topola/src/layout/primitives/mod.rs

@@ -15,6 +15,8 @@ pub use polygon::*;
 pub use segment::*;
 pub use via::*;
 
+use crate::{Layout, PinId};
+
 #[derive(Clone, Copy, Debug, Deserialize, Eq, From, Ord, PartialEq, PartialOrd, Serialize)]
 pub enum PrimitiveId {
     Joint(JointId),
@@ -22,3 +24,14 @@ pub enum PrimitiveId {
     Via(ViaId),
     Polygon(PolygonId),
 }
+
+impl Layout {
+    pub fn primitive_pin(&self, primitive: PrimitiveId) -> Option<PinId> {
+        match primitive {
+            PrimitiveId::Joint(joint_id) => self.joint(joint_id).spec.pin,
+            PrimitiveId::Segment(segment_id) => self.segment(segment_id).spec.pin,
+            PrimitiveId::Via(via_id) => self.via(via_id).spec.pin,
+            PrimitiveId::Polygon(polygon_id) => self.polygon(polygon_id).pin,
+        }
+    }
+}

topola/src/specctra.rs

@@ -12,8 +12,10 @@ use specctra::{
 
 use crate::{
     board::{Board, LayerDesc, LayerSide, LayerType},
-    layout::LayerId,
-    layout::compounds::{ComponentId, NetId, PinId},
+    layout::{
+        LayerId,
+        compounds::{ComponentId, NetId, PinId, PinSpec},
+    },
     primitives::{JointSpec, Polygon, Segment, SegmentSpec},
     vector::Vector2,
 };
@@ -161,7 +163,13 @@ impl Board {
                     let pin_name = format!("{}-{}", place.name, pin.id);
                     let net_id = pin_nets.get(&pin_name).copied();
 
-                    let pin_id = board.ensure_named_pin(pin_name.clone(), net_id);
+                    let pin_id = board.ensure_named_pin(
+                        pin_name.clone(),
+                        PinSpec {
+                            component: Some(component_id),
+                            net: net_id,
+                        },
+                    );
                     let padstack = dsn.pcb.library.find_padstack_by_name(&pin.name).unwrap();
 
                     for shape in padstack.shapes.iter() {