else:
                 region_y1 //= pixels_per_byte * self.colorspace.bytes_per_cell
                 region_y2 //= pixels_per_byte * self.colorspace.bytes_per_cell
             else:
                 region_y1 //= pixels_per_byte * self.colorspace.bytes_per_cell
                 region_y2 //= pixels_per_byte * self.colorspace.bytes_per_cell