Resets the user interface buttons for this widget.

def reset( self ):
        """
        Resets the user interface buttons for this widget.
        """
        # clear previous widgets
        for btn in self.findChildren(QToolButton):
            btn.close()
            btn.setParent(None)
            btn.deleteLater()
        
        # determine coloring options
        palette             = self.palette()
        unchecked           = palette.color(palette.Button)
        
        # determine if this is a dark or light scheme
        avg = (unchecked.red() + unchecked.green() + unchecked.blue()) / 3.0
        if ( avg < 140 ):
            checked             = unchecked.lighter(115)
            
            checked_clr         = self.colorString(unchecked.lighter(120))
            border_clr          = self.colorString(unchecked.darker(140))
            unchecked_clr       = self.colorString(checked.lighter(140))
            unchecked_clr_alt   = self.colorString(checked.lighter(120))
            checked_clr_alt     = self.colorString(unchecked)
        else:
            checked             = unchecked.lighter(120)
            
            checked_clr         = self.colorString(unchecked)
            border_clr          = self.colorString(unchecked.darker(160))
            unchecked_clr       = self.colorString(checked)
            unchecked_clr_alt   = self.colorString(checked.darker(130))
            checked_clr_alt     = self.colorString(unchecked.darker(120))
        
        # define the stylesheet options
        options = {}
        options['top_left_radius']      = 0
        options['top_right_radius']     = 0
        options['bot_left_radius']      = 0
        options['bot_right_radius']     = 0
        options['border_color']         = border_clr
        options['checked_clr']          = checked_clr
        options['checked_clr_alt']      = checked_clr_alt
        options['unchecked_clr']        = unchecked_clr
        options['unchecked_clr_alt']    = unchecked_clr_alt
        options['padding_top']          = 1
        options['padding_bottom']       = 1
        options['padding_left']         = 1
        options['padding_right']        = 1
        
        horiz = self.direction() in (QBoxLayout.LeftToRight, 
                                     QBoxLayout.RightToLeft)
        
        if ( horiz ):
            options['x1'] = 0
            options['y1'] = 0
            options['x2'] = 0
            options['y2'] = 1
        else:
            options['x1'] = 0
            options['y1'] = 0
            options['x2'] = 1
            options['y2'] = 1
        
        actions = self.actionGroup().actions()
        count = len(actions)
        for i, action in enumerate(actions):
            btn = QToolButton(self)
            btn.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)
            btn.setDefaultAction(action)
            self.layout().insertWidget(i, btn)
            
            options['top_left_radius']  = 1
            options['bot_left_radius']  = 1
            options['top_right_radius'] = 1
            options['bot_right_radius'] = 1
            
            if ( horiz ):
                options['padding_left']     = self._padding
                options['padding_right']    = self._padding
            else:
                options['padding_top']      = self._padding
                options['padding_bottom']   = self._padding
            
            if ( not i ):
                if ( horiz ):
                    options['top_left_radius'] = self.cornerRadius()
                    options['bot_left_radius'] = self.cornerRadius()
                    options['padding_left']    += self.cornerRadius() / 3.0
                else:
                    options['top_left_radius'] = self.cornerRadius()
                    options['top_right_radius'] = self.cornerRadius()
                    options['padding_top']     += self.cornerRadius() / 3.0
                    
            elif ( i == count - 1 ):
                if ( horiz ):
                    options['top_right_radius'] = self.cornerRadius()
                    options['bot_right_radius'] = self.cornerRadius()
                    options['padding_right']    += self.cornerRadius() / 3.0
                else:
                    options['bot_left_radius']  = self.cornerRadius()
                    options['bot_right_radius'] = self.cornerRadius()
                    options['padding_bottom']   += self.cornerRadius() / 3.0
            
            btn.setStyleSheet(TOOLBUTTON_STYLE % options)
            btn.setAutoFillBackground(True)