Adding seg-polyset collision support

common/geometry/shape_poly_set.cpp

@@ -1229,6 +1229,37 @@ bool SHAPE_POLY_SET::PointOnEdge( const VECTOR2I& aP ) const
 }
 
 
+bool SHAPE_POLY_SET::Collide( const SEG& aSeg, int aClearance ) const
+{
+
+    SHAPE_POLY_SET polySet = SHAPE_POLY_SET( *this );
+
+    // Inflate the polygon if necessary.
+    if( aClearance > 0 )
+    {
+        // fixme: the number of arc segments should not be hardcoded
+        polySet.Inflate( aClearance, 8 );
+    }
+
+    // We are going to check to see if the segment crosses an external
+    // boundary.  However, if the full segment is inside the polyset, this
+    // will not be true.  So we first test to see if one of the points is
+    // inside.  If true, then we collide
+    if( polySet.Contains( aSeg.A ) )
+        return true;
+
+    for( SEGMENT_ITERATOR iterator = polySet.IterateSegmentsWithHoles(); iterator; iterator++ )
+    {
+        SEG polygonEdge = *iterator;
+
+        if( polygonEdge.Intersect( aSeg, true ) )
+            return true;
+    }
+
+    return false;
+}
+
+
 bool SHAPE_POLY_SET::Collide( const VECTOR2I& aP, int aClearance ) const
 {
     SHAPE_POLY_SET polySet = SHAPE_POLY_SET( *this );

include/geometry/shape_poly_set.h

@@ -904,8 +904,19 @@ class SHAPE_POLY_SET : public SHAPE
          */
         bool Collide( const VECTOR2I& aP, int aClearance = 0 ) const override;
 
-        // fixme: add collision support
-        bool Collide( const SEG& aSeg, int aClearance = 0 ) const override { return false; }
+        /**
+         * Function Collide
+         * Checks whether the segment aSeg collides with the inside of the polygon set;  if the
+         * segment touches an edge or a corner of any of the polygons, there is no collision:
+         * the edges do not belong to the polygon itself.
+         * @param  aSeg       is the SEG segment whose collision with respect to the poly set
+         *                    will be tested.
+         * @param  aClearance is the security distance; if the segment passes closer to the polygon
+         *                    than aClearance distance, then there is a collision.
+         * @return bool - true if the segment aSeg collides with the polygon;
+         *                    false in any other case.
+         */
+        bool Collide( const SEG& aSeg, int aClearance = 0 ) const override;
 
         /**
          * Function CollideVertex