bool
GeoPointList::intersects( const GeoExtent& ex ) const
{
if ( ex.isInfinite() )
return true;
//TODO: srs transform
if ( ex.isPoint() ) // do a point-in-polygon test
{
const GeoPoint& point = ex.getSouthwest();
bool result = false;
const GeoPointList& polygon = *this;
for( unsigned int i=0, j=polygon.size()-1; i<polygon.size(); j = i++ )
{
if ((((polygon[i].y() <= point.y()) && (point.y() < polygon[j].y())) ||
((polygon[j].y() <= point.y()) && (point.y() < polygon[i].y()))) &&
(point.x() < (polygon[j].x()-polygon[i].x()) * (point.y()-polygon[i].y())/(polygon[j].y()-polygon[i].y())+polygon[i].x()))
{
result = !result;
}
}
return result;
}
else // check for all points within extent -- not actually correct //TODO
{
GeoExtent e;
for( GeoPointList::const_iterator i = begin(); i != end(); i++ )
{
if ( i == begin() ) e = GeoExtent( *i, *i );
else e.expandToInclude( *i );
}
return e.intersects( ex );
}
}
