Negative values for @pixels scroll left, positive values scroll right;
        @relative determines whether to set the scroll-x value or change as 
        above.

def scroll_x(self, pixels, relative=True):
        '''
        Negative values for @pixels scroll left, positive values scroll right;
        @relative determines whether to set the scroll-x value or change as 
        above.
        '''
        if relative:
            self.offset.x += int(pixels)
        else:
            self.offset.x = int(pixels)
        self._update()