From d155870275034c488349b85febb138e42d958f62 Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Thu, 21 Dec 2023 12:58:37 +0000
Subject: [PATCH] Sometimes use grid (instead of clearance) for slop radius.

This is particularly important both when very large grids
are in use, and when the router hasn't been initialized
with a net yet (ie: in hover mode) and the board clearance
is set to 0.

https://forum.kicad.info/t/new-track-start-position-problem-on-kicad-7-0-10-rc1/47006
---
 pcbnew/generators/pcb_tuning_pattern.cpp |  6 ++++--
 pcbnew/router/pns_router.cpp             | 26 ++++--------------------
 pcbnew/router/pns_router.h               |  2 +-
 pcbnew/router/pns_tool_base.cpp          |  5 +++--
 4 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/pcbnew/generators/pcb_tuning_pattern.cpp b/pcbnew/generators/pcb_tuning_pattern.cpp
index 4d9ae648b8..46d576049a 100644
--- a/pcbnew/generators/pcb_tuning_pattern.cpp
+++ b/pcbnew/generators/pcb_tuning_pattern.cpp
@@ -734,6 +734,8 @@ void PCB_TUNING_PATTERN::EditStart( GENERATOR_TOOL* aTool, BOARD* aBoard, BOARD_
 static PNS::LINKED_ITEM* pickSegment( PNS::ROUTER* aRouter, const VECTOR2I& aWhere, int aLayer,
                                       VECTOR2I& aPointOut )
 {
+    int maxSlopRadius = aRouter->Sizes().Clearance() + aRouter->Sizes().TrackWidth() / 2;
+
     static const int  candidateCount = 2;
     PNS::LINKED_ITEM* prioritized[candidateCount];
     SEG::ecoord       dist[candidateCount];
@@ -757,9 +759,9 @@ static PNS::LINKED_ITEM* pickSegment( PNS::ROUTER* aRouter, const VECTOR2I& aWhe
                 return false;
             };
 
-    for( bool useClearance : { false, true } )
+    for( int slopRadius : { 0, maxSlopRadius } )
     {
-        PNS::ITEM_SET candidates = aRouter->QueryHoverItems( aWhere, useClearance );
+        PNS::ITEM_SET candidates = aRouter->QueryHoverItems( aWhere, slopRadius );
 
         for( PNS::ITEM* item : candidates.Items() )
         {
diff --git a/pcbnew/router/pns_router.cpp b/pcbnew/router/pns_router.cpp
index 9a8828adef..8c0a6796e4 100644
--- a/pcbnew/router/pns_router.cpp
+++ b/pcbnew/router/pns_router.cpp
@@ -120,32 +120,14 @@ bool ROUTER::RoutingInProgress() const
 }
 
 
-const ITEM_SET ROUTER::QueryHoverItems( const VECTOR2I& aP, bool aUseClearance )
+const ITEM_SET ROUTER::QueryHoverItems( const VECTOR2I& aP, int aSlopRadius )
 {
-    NODE* node = nullptr;
-    int   clearance = 0;
-
-    if( m_state == IDLE || m_placer == nullptr )
-    {
-        node = m_world.get();
-        clearance = 0;
-    }
-    else if( m_mode == PNS_MODE_ROUTE_SINGLE )
-    {
-        node = m_placer->CurrentNode();
-        clearance = m_sizes.Clearance() + m_sizes.TrackWidth() / 2;
-    }
-    else if( m_mode == PNS_MODE_ROUTE_DIFF_PAIR )
-    {
-        node = m_placer->CurrentNode();
-        clearance = m_sizes.Clearance() + m_sizes.DiffPairWidth() / 2;
-    }
-
+    NODE*         node = m_placer ? m_placer->CurrentNode() : m_world.get();
     PNS::ITEM_SET ret;
 
     wxCHECK( node, ret );
 
-    if( aUseClearance )
+    if( aSlopRadius > 0 )
     {
         NODE::OBSTACLES          obs;
         SEGMENT                  test( SEG( aP, aP ), nullptr );
@@ -155,7 +137,7 @@ const ITEM_SET ROUTER::QueryHoverItems( const VECTOR2I& aP, bool aUseClearance )
         test.SetLayers( LAYER_RANGE::All() );
 
         opts.m_differentNetsOnly = false;
-        opts.m_overrideClearance = clearance;
+        opts.m_overrideClearance = aSlopRadius;
 
         node->QueryColliding( &test, obs, opts );
 
diff --git a/pcbnew/router/pns_router.h b/pcbnew/router/pns_router.h
index 9f3e23dac3..0b8679a352 100644
--- a/pcbnew/router/pns_router.h
+++ b/pcbnew/router/pns_router.h
@@ -181,7 +181,7 @@ public:
 
     bool IsPlacingVia() const;
 
-    const ITEM_SET QueryHoverItems( const VECTOR2I& aP, bool aUseClearance = false );
+    const ITEM_SET QueryHoverItems( const VECTOR2I& aP, int aSlopRadius = 0 );
 
     bool StartDragging( const VECTOR2I& aP, ITEM* aItem, int aDragMode = DM_ANY );
     bool StartDragging( const VECTOR2I& aP, ITEM_SET aItems, int aDragMode = DM_COMPONENT );
diff --git a/pcbnew/router/pns_tool_base.cpp b/pcbnew/router/pns_tool_base.cpp
index 2051ade04d..a200e7ca3a 100644
--- a/pcbnew/router/pns_tool_base.cpp
+++ b/pcbnew/router/pns_tool_base.cpp
@@ -100,6 +100,7 @@ ITEM* TOOL_BASE::pickSingleItem( const VECTOR2I& aWhere, NET_HANDLE aNet, int aL
                                  bool aIgnorePads, const std::vector<ITEM*> aAvoidItems )
 {
     int tl = aLayer > 0 ? aLayer : getView()->GetTopLayer();
+    int maxSlopRadius = std::max( m_gridHelper->GetGrid().x, m_gridHelper->GetGrid().y );
 
     static const int candidateCount = 5;
     ITEM* prioritized[candidateCount];
@@ -123,9 +124,9 @@ ITEM* TOOL_BASE::pickSingleItem( const VECTOR2I& aWhere, NET_HANDLE aNet, int aL
                 return false;
             };
 
-    for( bool useClearance : { false, true } )
+    for( int slopRadius : { 0, maxSlopRadius } )
     {
-        ITEM_SET candidates = m_router->QueryHoverItems( aWhere, useClearance );
+        ITEM_SET candidates = m_router->QueryHoverItems( aWhere, slopRadius );
 
         for( ITEM* item : candidates.Items() )
         {