class Framebuffer(object):
    def __init__(self, device_no: int):
        self.path = "/dev/fb%d" % device_no
        config_dir = "/sys/class/graphics/fb%d/" % device_no
        self.size = tuple(_read_and_convert_to_ints(
            config_dir + "/virtual_size"))
        self.stride = _read_and_convert_to_ints(config_dir + "/stride")[0]
        self.bits_per_pixel = _read_and_convert_to_ints(
            config_dir + "/bits_per_pixel")[0]
        assert self.stride == self.bits_per_pixel // 8 * self.size[0]
    def __str__(self):
        args = (self.path, self.size, self.stride, self.bits_per_pixel)
        return "%s  size:%s  stride:%s  bits_per_pixel:%s" % args
    # Note: performance is terrible even for medium resolutions
    def show(self, image: Image):
        converter = _CONVERTER[(image.mode, self.bits_per_pixel)]
        assert image.size == self.size
        out = converter(image)
        with open(self.path, "wb") as fp:
            fp.write(out)
    def on(self):
        pass
    def off(self):
        pass