From 1122d80388793846ea6eb8455b476a8acd7622be Mon Sep 17 00:00:00 2001
From: Alex Shvartzkop <dudesuchamazing@gmail.com>
Date: Wed, 31 Jan 2024 23:38:05 +0300
Subject: [PATCH] Better support for arcs in tuning patterns.

---
 libs/kimath/include/geometry/shape_arc.h |  2 ++
 libs/kimath/src/geometry/shape_arc.cpp   | 23 +++++++++++++++++
 pcbnew/generators/pcb_tuning_pattern.cpp | 32 +++++++++++++++---------
 3 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/libs/kimath/include/geometry/shape_arc.h b/libs/kimath/include/geometry/shape_arc.h
index 526b494802..ce306c44fd 100644
--- a/libs/kimath/include/geometry/shape_arc.h
+++ b/libs/kimath/include/geometry/shape_arc.h
@@ -116,6 +116,8 @@ public:
 
     const BOX2I BBox( int aClearance = 0 ) const override;
 
+    VECTOR2I NearestPoint( const VECTOR2I& aP ) const;
+
     bool Collide( const SEG& aSeg, int aClearance = 0, int* aActual = nullptr,
                   VECTOR2I* aLocation = nullptr ) const override;
     bool Collide( const VECTOR2I& aP, int aClearance = 0, int* aActual = nullptr,
diff --git a/libs/kimath/src/geometry/shape_arc.cpp b/libs/kimath/src/geometry/shape_arc.cpp
index 2257620961..f59b42be5a 100644
--- a/libs/kimath/src/geometry/shape_arc.cpp
+++ b/libs/kimath/src/geometry/shape_arc.cpp
@@ -370,6 +370,29 @@ bool SHAPE_ARC::IsClockwise() const
 }
 
 
+VECTOR2I SHAPE_ARC::NearestPoint( const VECTOR2I& aP ) const
+{
+    const static int s_epsilon = 8;
+
+    CIRCLE   fullCircle( GetCenter(), GetRadius() );
+    VECTOR2I nearestPt = fullCircle.NearestPoint( aP );
+
+    if( ( nearestPt - m_start ).SquaredEuclideanNorm() <= s_epsilon )
+        return m_start;
+
+    if( ( nearestPt - m_end ).SquaredEuclideanNorm() <= s_epsilon )
+        return m_end;
+
+    if( sliceContainsPoint( nearestPt ) )
+        return nearestPt;
+
+    if( ( aP - m_start ).SquaredEuclideanNorm() <= ( aP - m_end ).SquaredEuclideanNorm() )
+        return m_start;
+    else
+        return m_end;
+}
+
+
 bool SHAPE_ARC::Collide( const VECTOR2I& aP, int aClearance, int* aActual,
                          VECTOR2I* aLocation ) const
 {
diff --git a/pcbnew/generators/pcb_tuning_pattern.cpp b/pcbnew/generators/pcb_tuning_pattern.cpp
index a73a60cafc..75245da07a 100644
--- a/pcbnew/generators/pcb_tuning_pattern.cpp
+++ b/pcbnew/generators/pcb_tuning_pattern.cpp
@@ -597,9 +597,22 @@ static VECTOR2I snapToNearestTrack( const VECTOR2I& aP, BOARD* aBoard, NETINFO_I
         if( aNet && track->GetNet() != aNet )
             continue;
 
-        SEG seg( track->GetStart(), track->GetEnd() );
+        VECTOR2I nearest;
+
+        if( track->Type() == PCB_ARC_T )
+        {
+            PCB_ARC*  pcbArc = static_cast<PCB_ARC*>( track );
+            SHAPE_ARC arc( pcbArc->GetStart(), pcbArc->GetMid(), pcbArc->GetEnd(),
+                           pcbArc->GetWidth() );
+
+            nearest = arc.NearestPoint( aP );
+        }
+        else
+        {
+            SEG seg( track->GetStart(), track->GetEnd() );
+            nearest = seg.NearestPoint( aP );
+        }
 
-        VECTOR2I    nearest = seg.NearestPoint( aP );
         SEG::ecoord dist_sq = ( nearest - aP ).SquaredEuclideanNorm();
 
         if( dist_sq < minDist_sq )
@@ -807,21 +820,16 @@ static PNS::LINKED_ITEM* pickSegment( PNS::ROUTER* aRouter, const VECTOR2I& aWhe
 
             if( item->Kind() & PNS::ITEM::ARC_T )
             {
-                SEG::ecoord d0 = ( item->Anchor( 0 ) - aWhere ).SquaredEuclideanNorm();
-                SEG::ecoord d1 = ( item->Anchor( 1 ) - aWhere ).SquaredEuclideanNorm();
+                PNS::ARC* pnsArc = static_cast<PNS::ARC*>( item );
+
+                VECTOR2I    nearest = pnsArc->Arc().NearestPoint( aWhere );
+                SEG::ecoord d0 = ( nearest - aWhere ).SquaredEuclideanNorm();
 
                 if( d0 <= dist[1] )
                 {
                     prioritized[1] = linked;
                     dist[1] = d0;
-                    point[1] = item->Anchor( 0 );
-                }
-
-                if( d1 <= dist[1] )
-                {
-                    prioritized[1] = linked;
-                    dist[1] = d1;
-                    point[1] = item->Anchor( 1 );
+                    point[1] = nearest;
                 }
             }
             else if( item->Kind() & PNS::ITEM::SEGMENT_T )