Stretch
- class ipkiss3.all.Stretch
- Non-homothetic scaling. - Parameters:
- stretch_factor: optional
- stretch factor (x, y) 
- stretch_center: Coord2, optional
 
 - apply_to_coord(coord)
- apply transformation to coordinate 
 - reverse_on_coord(coord)
- apply reverse transformation to coordinate 
 - apply_to_array(coords)
- apply transformation to numpy array 
 - reverse_on_array(coords)
- internal use: applies reverse transformation to a numpy array 
 - is_identity()
- returns True if the transformation does nothing 
 - is_isometric()
- returns True if the transformation conserves angles and distances 
 - is_homothetic()
- returns True if the transformation conserves angles