PNS: Detect collisions including newline width

The new line collision search uses BBox() to check for colliding
objects.  BBox in the SHAPE_LINE_CHAIN did not include width as the
chains were assumed to be zero-width.  This is not the case for
PNS::LINE elements.

We mostly don't notice this because DRC checks for SEGMENT collisions
but it becomes obvious/annoying when we cannot place a track for unknown
reasons and the snap-back doesn't take line width into account.

Fixes #3776 | https://gitlab.com/kicad/code/kicad/issues/3776

(cherry picked from commit fe15511d38)

include/geometry/shape_line_chain.h

@@ -74,15 +74,17 @@ public:
      * Constructor
      * Initializes an empty line chain.
      */
-    SHAPE_LINE_CHAIN() :
+    SHAPE_LINE_CHAIN() : SHAPE( SH_LINE_CHAIN ), m_closed( false ), m_width( 0 )
-        SHAPE( SH_LINE_CHAIN ), m_closed( false )
     {}
 
     /**
      * Copy Constructor
      */
-    SHAPE_LINE_CHAIN( const SHAPE_LINE_CHAIN& aShape ) :
+    SHAPE_LINE_CHAIN( const SHAPE_LINE_CHAIN& aShape )
-        SHAPE( SH_LINE_CHAIN ), m_points( aShape.m_points ), m_closed( aShape.m_closed )
+            : SHAPE( SH_LINE_CHAIN ),
+              m_points( aShape.m_points ),
+              m_closed( aShape.m_closed ),
+              m_width( aShape.m_width )
     {}
 
     /**
@@ -90,7 +92,7 @@ public:
      * Initializes a 2-point line chain (a single segment)
      */
     SHAPE_LINE_CHAIN( const VECTOR2I& aA, const VECTOR2I& aB ) :
-        SHAPE( SH_LINE_CHAIN ), m_closed( false )
+        SHAPE( SH_LINE_CHAIN ), m_closed( false ), m_width( 0 )
     {
         m_points.resize( 2 );
         m_points[0] = aA;
@@ -98,7 +100,7 @@ public:
     }
 
     SHAPE_LINE_CHAIN( const VECTOR2I& aA, const VECTOR2I& aB, const VECTOR2I& aC ) :
-        SHAPE( SH_LINE_CHAIN ), m_closed( false )
+        SHAPE( SH_LINE_CHAIN ), m_closed( false ), m_width( 0 )
     {
         m_points.resize( 3 );
         m_points[0] = aA;
@@ -107,7 +109,7 @@ public:
     }
 
     SHAPE_LINE_CHAIN( const VECTOR2I& aA, const VECTOR2I& aB, const VECTOR2I& aC, const VECTOR2I& aD ) :
-        SHAPE( SH_LINE_CHAIN ), m_closed( false )
+        SHAPE( SH_LINE_CHAIN ), m_closed( false ), m_width( 0 )
     {
         m_points.resize( 4 );
         m_points[0] = aA;
@@ -119,7 +121,8 @@ public:
 
     SHAPE_LINE_CHAIN( const VECTOR2I* aV, int aCount ) :
         SHAPE( SH_LINE_CHAIN ),
-        m_closed( false )
+        m_closed( false ),
+        m_width( 0 )
     {
         m_points.resize( aCount );
 
@@ -127,9 +130,8 @@ public:
             m_points[i] = *aV++;
     }
 
-    SHAPE_LINE_CHAIN( const ClipperLib::Path& aPath ) :
+    SHAPE_LINE_CHAIN( const ClipperLib::Path& aPath )
-        SHAPE( SH_LINE_CHAIN ),
+            : SHAPE( SH_LINE_CHAIN ), m_closed( true ), m_width( 0 )
-        m_closed( true )
     {
         m_points.reserve( aPath.size() );
 
@@ -174,6 +176,24 @@ public:
         return m_closed;
     }
 
+    /**
+     * Sets the width of all segments in the chain
+     * @param aWidth width in internal units
+     */
+    void SetWidth( int aWidth )
+    {
+        m_width = aWidth;
+    }
+
+    /**
+     * Gets the current width of the segments in the chain
+     * @return width in internal units
+     */
+    int Width() const
+    {
+        return m_width;
+    }
+
     /**
      * Function SegmentCount()
      *
@@ -299,8 +319,8 @@ public:
         BOX2I bbox;
         bbox.Compute( m_points );
 
-        if( aClearance != 0 )
+        if( aClearance != 0 || m_width != 0 )
-            bbox.Inflate( aClearance );
+            bbox.Inflate( aClearance + m_width );
 
         return bbox;
     }
@@ -684,6 +704,12 @@ private:
     /// is the line chain closed?
     bool m_closed;
 
+    /// Width of the segments (for BBox calculations in RTree)
+    /// TODO Adjust usage of SHAPE_LINE_CHAIN to account for where we need a width and where not
+    /// Alternatively, we could split the class into a LINE_CHAIN (no width) and SHAPE_LINE_CHAIN that derives from
+    /// SHAPE as well that does have a width.  Not sure yet on the correct path.
+    int m_width;
+
     /// cached bounding box
     BOX2I m_bbox;
 };

pcbnew/router/pns_line.h

@@ -105,6 +105,7 @@ public:
     void SetShape( const SHAPE_LINE_CHAIN& aLine )
     {
         m_line = aLine;
+        m_line.SetWidth( m_width );
     }
 
     ///> Returns the shape of the line
@@ -153,6 +154,7 @@ public:
     void SetWidth( int aWidth )
     {
         m_width = aWidth;
+        m_line.SetWidth( aWidth );
     }
 
     ///> Returns line width