router: take net clearance when deskewing diff pairs.

Apply correction on DP corner radius to avoid DRC issues.

pcbnew/router/pns_meander.cpp

@@ -198,14 +198,34 @@ SHAPE_LINE_CHAIN PNS_MEANDER_SHAPE::circleQuad( VECTOR2D aP, VECTOR2D aDir, bool
 
     const int ArcSegments = Settings().m_cornerArcSegments;
 
+    double radius = (double) aDir.EuclideanNorm();
+    double angleStep = M_PI / 2.0 / (double) ArcSegments;
+
+    double correction = 12.0 * radius * ( 1.0 - cos( angleStep / 2.0 ) );
+
+    if( !m_dual )
+        correction = 0.0;
+    else if( radius < m_meanCornerRadius )
+        correction = 0.0;
+
+    VECTOR2D p = aP;
+    lc.Append( ( int ) p.x, ( int ) p.y );
+
+    VECTOR2D dir_uu = dir_u.Resize( radius - correction );
+    VECTOR2D dir_vv = dir_v.Resize( radius - correction );
+
+    VECTOR2D shift = dir_u.Resize( correction );
+
     for( int i = ArcSegments - 1; i >= 0; i-- )
     {
-        VECTOR2D p;
         double alpha = (double) i / (double) ( ArcSegments - 1 ) * M_PI / 2.0;
-        p = aP + dir_u * cos( alpha ) + dir_v * ( aSide ? -1.0 : 1.0 ) * ( 1.0 - sin( alpha ) );
+        p = aP + shift + dir_uu * cos( alpha ) + dir_vv * ( aSide ? -1.0 : 1.0 ) * ( 1.0 - sin( alpha ) );
         lc.Append( ( int ) p.x, ( int ) p.y );
     }
 
+    p = aP + dir_u + dir_v * ( aSide ? -1.0 : 1.0 );
+    lc.Append( ( int ) p.x, ( int ) p.y );
+
     return lc;
 }
 
@@ -303,6 +323,8 @@ SHAPE_LINE_CHAIN PNS_MEANDER_SHAPE::genMeanderShape( VECTOR2D aP, VECTOR2D aDir,
         cr = spc / 2;
     }
 
+    m_meanCornerRadius = cr;
+
     SHAPE_LINE_CHAIN lc;
 
     start( &lc, aP + dir_v_b, aDir );

pcbnew/router/pns_meander.h

@@ -360,6 +360,8 @@ private:
     int m_amplitude;
     ///> offset wrs the base segment (dual only)
     int m_baselineOffset;
+    ///> average radius of meander corners (for correction of DP meanders)
+    int m_meanCornerRadius;
     ///> first point of the meandered line
     VECTOR2I m_p0;
     ///> base segment (unclipped)

pcbnew/router/pns_node.h

@@ -66,6 +66,8 @@ public:
     virtual int operator()( const PNS_ITEM* aA, const PNS_ITEM* aB );
     virtual void OverrideClearance (bool aEnable, int aNetA = 0, int aNetB = 0, int aClearance = 0);
 
+    void UseDpGap( bool aUseDpGap ) { m_useDpGap = aUseDpGap; }
+
 private:
     struct CLEARANCE_ENT {
         int coupledNet;
@@ -80,6 +82,7 @@ private:
     bool m_overrideEnabled;
     int m_overrideNetA, m_overrideNetB;
     int m_overrideClearance;
+    bool m_useDpGap;
 };
 
 /**

pcbnew/router/pns_router.cpp

@@ -72,6 +72,7 @@ PNS_PCBNEW_CLEARANCE_FUNC::PNS_PCBNEW_CLEARANCE_FUNC( PNS_ROUTER* aRouter ) :
 
     PNS_TOPOLOGY topo( world );
     m_clearanceCache.resize( brd->GetNetCount() );
+    m_useDpGap = false;
 
     for( unsigned int i = 0; i < brd->GetNetCount(); i++ )
     {
@@ -128,7 +129,7 @@ int PNS_PCBNEW_CLEARANCE_FUNC::operator()( const PNS_ITEM* aA, const PNS_ITEM* a
     if( net_a == net_b )
         return 0;
 
-    if( linesOnly && net_a >= 0 && net_b >= 0 && m_clearanceCache[net_a].coupledNet == net_b )
+    if( m_useDpGap && linesOnly && net_a >= 0 && net_b >= 0 && m_clearanceCache[net_a].coupledNet == net_b )
     {
         cl_a = cl_b = m_router->Sizes().DiffPairGap() - 2 * PNS_HULL_MARGIN;
     }
@@ -608,6 +609,8 @@ bool PNS_ROUTER::StartDragging( const VECTOR2I& aP, PNS_ITEM* aStartItem )
 
 bool PNS_ROUTER::StartRouting( const VECTOR2I& aP, PNS_ITEM* aStartItem, int aLayer )
 {
+    m_clearanceFunc->UseDpGap( false );
+
     switch( m_mode )
     {
         case PNS_MODE_ROUTE_SINGLE:
@@ -615,6 +618,7 @@ bool PNS_ROUTER::StartRouting( const VECTOR2I& aP, PNS_ITEM* aStartItem, int aLa
             break;
         case PNS_MODE_ROUTE_DIFF_PAIR:
             m_placer = new PNS_DIFF_PAIR_PLACER( this );
+            m_clearanceFunc->UseDpGap( true );
             break;
         case PNS_MODE_TUNE_SINGLE:
             m_placer = new PNS_MEANDER_PLACER( this );

pcbnew/router/pns_router.h

@@ -272,7 +272,7 @@ private:
     // optHoverItem m_startItem, m_endItem;
 
     PNS_ROUTING_SETTINGS m_settings;
-    PNS_CLEARANCE_FUNC* m_clearanceFunc;
+    PNS_PCBNEW_CLEARANCE_FUNC* m_clearanceFunc;
 
     boost::unordered_set<BOARD_CONNECTED_ITEM*> m_hiddenItems;