def _do_crop(self, lines, width, height, x_crop, y_crop):
        '''Crops a list of strings to the specified width/height
        '''
        lines = crop_or_expand(
            lines, height, default=[self.fillchar * width],
            scheme=self._schemes[y_crop])
        for i, line in enumerate(lines):
            lines[i] = crop_or_expand(
                line, width, default=self.fillchar,
                scheme=self._schemes[x_crop])
        return lines