Length Tuner: Allow controlling the side of the meander using the cursor

Also fixes an issue that did not allow single meanders to be placed

pcbnew/router/pns_dp_meander_placer.cpp

@@ -254,7 +254,7 @@ bool DP_MEANDER_PLACER::Move( const VECTOR2I& aP, ITEM* aEndItem )
             curIndexN = tunedN.NextShape( curIndexN );
         }
 
-        m_result.MeanderSegment( base );
+        m_result.MeanderSegment( base, base.Side( aP ) < 0 );
     }
 
     while( curIndexP < tunedP.PointCount() && curIndexP != -1 )

pcbnew/router/pns_meander.cpp

@@ -42,13 +42,13 @@ const MEANDER_SETTINGS& MEANDERED_LINE::Settings() const
 }
 
 
-void MEANDERED_LINE::MeanderSegment( const SEG& aBase, int aBaseIndex )
+void MEANDERED_LINE::MeanderSegment( const SEG& aBase, bool aSide, int aBaseIndex )
 {
     double base_len = aBase.Length();
 
     SHAPE_LINE_CHAIN lc;
 
-    bool side = true;
+    bool side = aSide;
     VECTOR2D dir( aBase.B - aBase.A );
 
     if( !m_dual )
@@ -80,11 +80,13 @@ void MEANDERED_LINE::MeanderSegment( const SEG& aBase, int aBaseIndex )
             {
                 for( int i = 0; i < 2; i++ )
                 {
-                    if( m.Fit( MT_CHECK_START, aBase, m_last, i ) )
+                    bool checkSide = ( i == 0 ) ? side : !side;
+
+                    if( m.Fit( MT_CHECK_START, aBase, m_last, checkSide ) )
                     {
                         turning = true;
                         AddMeander( new MEANDER_SHAPE( m ) );
-                        side = !i;
+                        side = !checkSide;
                         started = true;
                         break;
                     }
@@ -96,12 +98,14 @@ void MEANDERED_LINE::MeanderSegment( const SEG& aBase, int aBaseIndex )
 
                     for( int i = 0; i < 2; i++ )
                     {
-                        if( m.Fit( MT_SINGLE, aBase, m_last, i ) )
+                        bool checkSide = ( i == 0 ) ? side : !side;
+
+                        if( m.Fit( MT_SINGLE, aBase, m_last, checkSide ) )
                         {
                             AddMeander( new MEANDER_SHAPE( m ) );
                             fail = false;
                             started = false;
-                            side = !i;
+                            side = !checkSide;
                             break;
                         }
                     }

pcbnew/router/pns_meander.h

@@ -472,9 +472,10 @@ public:
      * Fit maximum amplitude meanders on a given segment and adds to the current line.
      *
      * @param aSeg the base segment to meander.
+     * @param aSide Side to start meandering the segment. True=left, False=Right
      * @param aBaseIndex index of the base segment in the original line.
      */
-    void MeanderSegment( const SEG& aSeg, int aBaseIndex = 0 );
+    void MeanderSegment( const SEG& aSeg, bool aSide, int aBaseIndex = 0 );
 
     /// @copydoc MEANDER_SHAPE::SetBaselineOffset()
     void SetBaselineOffset( int aOffset )

pcbnew/router/pns_meander_placer.cpp

@@ -139,7 +139,7 @@ bool MEANDER_PLACER::doMove( const VECTOR2I& aP, ITEM* aEndItem, long long int a
 
         const SEG s = tuned.CSegment( i );
         m_result.AddCorner( s.A );
-        m_result.MeanderSegment( s );
+        m_result.MeanderSegment( s, s.Side( aP ) < 0 );
         m_result.AddCorner( s.B );
     }