| this is a common ancestor for all children of oasa.chem_vertex in bkchem. It adds some
  basic functionality to the chem_vertex so that it is not needed to add it every child;
  all the methods are tuned for always shown texts; atoms need to override something 
        
            | Methods |  |  
        |  |  
            |  | __init__ |  
        | 
__init__ (
        self,
        standard=None,
        xy=(),
        molecule=None,
        )
 |  
            |  | bbox |  
        | 
bbox ( self )
 returns the bounding box of the object as a list of [x1,y1,x2,y2] |  
            |  | copy_settings |  
        | 
copy_settings ( self,  other )
 copies settings of self to other, does not check if other is capable of receiving it |  
            |  | decide_pos |  
        | 
decide_pos ( self )
 decides whether the first or the last letter in the text should be positioned on the
    coords of the vertex |  
            |  | delete |  
        | 
delete ( self )
 |  
            |  | draw |  
        | 
draw ( self,  redraw=False )
 draws vertex with respect to its properties |  
            |  | focus |  
        | 
focus ( self )
 |  
            |  | get_xy |  
        | 
get_xy ( self )
 |  
            |  | get_xyz |  
        | 
get_xyz ( self,  real=0 )
 returns atoms coordinates, default are screen coordinates, real!=0
    changes it to real coordinates (these two are usually different for imported molecules) |  
            |  | lift |  
        | 
lift ( self )
 |  
            |  | lift_selector |  
        | 
lift_selector ( self )
 |  
            |  | move |  
        | 
move (
        self,
        dx,
        dy,
        dont_move_marks=False,
        )
moves object with his selector (when present) |  
            |  | move_to |  
        | 
move_to (
        self,
        x,
        y,
        dont_move_marks=False,
        )
 |  
            |  | redraw |  
        | 
redraw ( self,  suppress_reposition=0 )
 |  
            |  | scale_font |  
        | 
scale_font ( self,  ratio )
 scales font of atom. does not redraw !! |  
            |  | select |  
        | 
select ( self )
 |  
            |  | toggle_center |  
        | 
toggle_center ( self,  mode=0 )
 toggles the centering of text between center-firstandcenter-last(mode=0)
    or sets it strictly - mode=-1, mode=1 |  
            |  | transform |  
        | 
transform ( self,  tr )
 |  
            |  | unfocus |  
        | 
unfocus ( self )
 |  
            |  | unselect |  
        | 
unselect ( self )
 |  
            |  | update_font |  
        | 
update_font ( self )
 |  |