codecs.py 文件源码

def compress_zip_prediction(fd,      # type: BinaryIO
                            image,   # type: np.ndarray
                            depth,   # type: int
                            version  # type: int
                            ):       # type: (...) -> None
    """
    Write a Numpy array to a zip (zlib) with prediction compressed
    stream.

    Not supported for 1- or 32-bit images.

{}
    """
    if depth == 1:  # pragma: no cover
        raise ValueError(
            "zip with prediction is not supported for 1-bit images")
    elif depth == 32:  # pragma: no cover
        raise ValueError(
            "zip with prediction is not implemented for 32-bit images")
    elif depth == 8:
        encoder = packbits.encode_prediction_8bit
    elif depth == 16:
        encoder = packbits.encode_prediction_16bit

    compressor = zlib.compressobj()
    for row in image:
        encoder(row.flatten())
        row = util.ensure_bigendian(row)
        fd.write(compressor.compress(row))
    fd.write(compressor.flush())