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;
}
