def get_real_label_width( self, lev, fmt, fsize ):
<EOL>xx = np.mean( np.asarray(self.ax.axis()).reshape(<NUM_LIT:2>,<NUM_LIT:2>), axis=<NUM_LIT:1> )<EOL>t = text.Text( xx[<NUM_LIT:0>], xx[<NUM_LIT:1>] )<EOL>self.set_label_props( t, self.get_text(lev,fmt), '<STR_LIT:k>' )<EOL>bbox = t.get_window_extent(renderer=self.ax.figure.canvas.renderer)<EOL>lw = np.diff(bbox.corners()[<NUM_LIT:0>::<NUM_LIT:2>,<NUM_LIT:0>])[<NUM_LIT:0>]<EOL>return lw<EOL>
This computes actual onscreen label width.
This uses some black magic to determine onscreen extent of non-drawn
label.  This magic may not be very robust.