bool PNS_LINE::Walkaround( SHAPE_LINE_CHAIN aObstacle, SHAPE_LINE_CHAIN& aPre, SHAPE_LINE_CHAIN& aWalk, SHAPE_LINE_CHAIN& aPost, bool aCw ) const { const SHAPE_LINE_CHAIN& line ( CLine() ); VECTOR2I ip_start; VECTOR2I ip_end; if( line.SegmentCount() < 1 ) return false; if( aObstacle.PointInside( line.CPoint( 0 ) ) || aObstacle.PointInside( line.CPoint( -1 ) ) ) return false; SHAPE_LINE_CHAIN::INTERSECTIONS ips, ips2; line.Intersect( aObstacle, ips ); int nearest_dist = INT_MAX; int farthest_dist = 0; SHAPE_LINE_CHAIN::INTERSECTION nearest, farthest; for( int i = 0; i < (int) ips.size(); i++ ) { const VECTOR2I p = ips[i].p; int dist = line.PathLength( p ); if( dist < 0 ) return false; if( dist <= nearest_dist ) { nearest_dist = dist; nearest = ips[i]; } if( dist >= farthest_dist ) { farthest_dist = dist; farthest = ips[i]; } } if( ips.size() <= 1 || nearest.p == farthest.p ) { aPre = line; return true; } aPre = line.Slice( 0, nearest.our.Index() ); aPre.Append( nearest.p ); aPre.Simplify(); aWalk.Clear(); aWalk.SetClosed( false ); aWalk.Append( nearest.p ); int i = nearest.their.Index(); assert( nearest.their.Index() >= 0 ); assert( farthest.their.Index() >= 0 ); assert( nearest_dist <= farthest_dist ); aObstacle.Split( nearest.p ); aObstacle.Split( farthest.p ); int i_first = aObstacle.Find( nearest.p ); int i_last = aObstacle.Find( farthest.p ); i = i_first; while( i != i_last ) { aWalk.Append( aObstacle.CPoint( i ) ); i += ( aCw ? 1 : -1 ); if( i < 0 ) i = aObstacle.PointCount() - 1; else if( i == aObstacle.PointCount() ) i = 0; } aWalk.Append( farthest.p ); aWalk.Simplify(); aPost.Clear(); aPost.Append( farthest.p ); aPost.Append( line.Slice( farthest.our.Index() + 1, -1 ) ); aPost.Simplify(); return true; }