Sets the pixmap size for this label.
        
        :param      size | <QSize>

def setPixmapSize(self, size):
        """
        Sets the pixmap size for this label.
        
        :param      size | <QSize>
        """
        self._pixmapSize = size
        self.setPixmap(self.action().icon().pixmap(size))
        
        max_size = self.parent().maximumPixmapSize()
        
        if self.position() in (XDockToolbar.Position.North,
                               XDockToolbar.Position.South):
            self.setFixedWidth(size.width() + self.padding())
            self.setFixedHeight(max_size.height() + self.padding())
        else:
            self.setFixedWidth(max_size.width() + self.padding())
            self.setFixedHeight(size.height() + self.padding())