From 70c6314c6719d45ab22af74f978d53e0a8c1d24b Mon Sep 17 00:00:00 2001
From: Jon Evans <jon@craftyjon.com>
Date: Tue, 22 Dec 2020 22:28:13 -0500
Subject: [PATCH] Component dragger: be more generous about picking up tracks

We now pick up tracks that end anywhere in the pad, not just
at the pad anchor.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/5945
---
 pcbnew/router/pns_component_dragger.cpp | 48 +++++++++++++++++++------
 pcbnew/router/pns_component_dragger.h   |  1 +
 pcbnew/router/pns_node.cpp              | 17 +++++----
 3 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/pcbnew/router/pns_component_dragger.cpp b/pcbnew/router/pns_component_dragger.cpp
index e8f8673c60..621d369db8 100644
--- a/pcbnew/router/pns_component_dragger.cpp
+++ b/pcbnew/router/pns_component_dragger.cpp
@@ -50,6 +50,26 @@ bool COMPONENT_DRAGGER::Start( const VECTOR2I& aP, ITEM_SET& aPrimitives )
     m_initialDraggedItems = aPrimitives;
     m_p0                  = aP;
 
+    std::unordered_set<LINKED_ITEM*> seenItems;
+
+    auto addLinked =
+            [&]( SOLID* aSolid, LINKED_ITEM* aItem, VECTOR2I aOffset = {} )
+            {
+                if( seenItems.count( aItem ) )
+                    return;
+
+                seenItems.insert( aItem );
+
+                int segIndex;
+                DRAGGED_CONNECTION cn;
+
+                cn.origLine    = m_world->AssembleLine( aItem, &segIndex );
+                cn.attachedPad = aSolid;
+                cn.offset      = aOffset;
+
+                m_conns.push_back( cn );
+            };
+
     for( auto item : aPrimitives.Items() )
     {
         if( item.item->Kind() != ITEM::SOLID_T )
@@ -66,17 +86,23 @@ bool COMPONENT_DRAGGER::Start( const VECTOR2I& aP, ITEM_SET& aPrimitives )
         for( auto link : jt->LinkList() )
         {
             if( link.item->OfKind( ITEM::SEGMENT_T | ITEM::ARC_T ) )
+                addLinked( solid, static_cast<LINKED_ITEM*>( link.item ) );
+        }
+
+        std::vector<JOINT*> extraJoints;
+
+        if( m_world->QueryJoints( solid->Hull().BBox(), extraJoints, solid->Layer(),
+                                  ITEM::SEGMENT_T | ITEM::ARC_T ) )
+        {
+            for( JOINT* extraJoint : extraJoints )
             {
-                LINKED_ITEM* li = static_cast<LINKED_ITEM*>( link.item );
-                int          segIndex;
+                if( extraJoint->Net() == jt->Net() && extraJoint->LinkCount() == 1 )
+                {
+                    LINKED_ITEM* li = static_cast<LINKED_ITEM*>( extraJoint->LinkList()[0].item );
 
-                auto l0 = m_world->AssembleLine( li, &segIndex );
-
-                DRAGGED_CONNECTION cn;
-
-                cn.origLine    = l0;
-                cn.attachedPad = solid;
-                m_conns.push_back( cn );
+                    if( li->Collide( solid, 0, false, nullptr, nullptr, false ) )
+                        addLinked( solid, li, extraJoint->Pos() - solid->Pos() );
+                }
             }
         }
     }
@@ -108,8 +134,8 @@ bool COMPONENT_DRAGGER::Drag( const VECTOR2I& aP )
         {
             if( l.attachedPad == s )
             {
-                l.p_orig = s->Pos();
-                l.p_next = p_next;
+                l.p_orig = s->Pos() + l.offset;
+                l.p_next = p_next + l.offset;
             }
         }
     }
diff --git a/pcbnew/router/pns_component_dragger.h b/pcbnew/router/pns_component_dragger.h
index 0be7e3de3f..049938a362 100644
--- a/pcbnew/router/pns_component_dragger.h
+++ b/pcbnew/router/pns_component_dragger.h
@@ -114,6 +114,7 @@ private:
         LINE     origLine;
         SOLID*   attachedPad;
         VECTOR2I p_orig, p_next;
+        VECTOR2I offset;
     };
 
     std::set<SOLID*>                m_solids;
diff --git a/pcbnew/router/pns_node.cpp b/pcbnew/router/pns_node.cpp
index 0bf4066879..bd467a934a 100644
--- a/pcbnew/router/pns_node.cpp
+++ b/pcbnew/router/pns_node.cpp
@@ -1424,11 +1424,14 @@ int NODE::QueryJoints( const BOX2I& aBox, std::vector<JOINT*>& aJoints, int aLay
 
     aJoints.clear();
 
-    for( auto j = m_joints.begin(); j != m_joints.end(); ++j )
+    for( JOINT_MAP::value_type& j : m_joints )
     {
-        if( aBox.Contains( j->second.Pos() ) && j->second.LinkCount( aKindMask ) )
+        if( j.second.Layer() != aLayerMask )
+            continue;
+
+        if( aBox.Contains( j.second.Pos() ) && j.second.LinkCount( aKindMask ) )
         {
-            aJoints.push_back( &j->second );
+            aJoints.push_back( &j.second );
             n++;
         }
     }
@@ -1436,13 +1439,13 @@ int NODE::QueryJoints( const BOX2I& aBox, std::vector<JOINT*>& aJoints, int aLay
     if( isRoot() )
         return n;
 
-    for( auto j = m_root->m_joints.begin(); j != m_root->m_joints.end(); ++j )
+    for( JOINT_MAP::value_type& j : m_root->m_joints )
     {
-        if( !Overrides( &j->second) )
+        if( !Overrides( &j.second ) && j.second.Layer() == aLayerMask )
         {
-            if( aBox.Contains( j->second.Pos() ) && j->second.LinkCount( aKindMask ) )
+            if( aBox.Contains( j.second.Pos() ) && j.second.LinkCount( aKindMask ) )
             {
-                aJoints.push_back( &j->second );
+                aJoints.push_back( &j.second );
                 n++;
             }
         }