TiffWriter.py 文件源码

def flatten_and_pack(img, bits):
    """
    Packs reduced bit depth images into bytes and returns a flattened array
        Args:
            img (uint8 numpy array): grayscale or multi-channel image
            bits (int): 1, 2, 4, or 8 bits per channel
        Returns:
            uint8 numpy array: flattened and packed array
    """

    # pad the image at the end of the rows, so that each row ends on a byte boundary
    pixels_per_byte = 8 // bits
    if len(img.shape) > 1:
        if img.shape[1] % pixels_per_byte != 0:
            img = np.hstack((img, np.zeros((img.shape[0], pixels_per_byte - img.shape[1] % pixels_per_byte), dtype=np.uint8)))

    a = np.right_shift(img, 8-bits)                                             # reduce bit depth
    b = a.flatten()                                                             # flatten
    c = np.zeros(b.size // pixels_per_byte, dtype=np.uint8)
    for i in range(0, pixels_per_byte):
        c += np.left_shift(b[i::pixels_per_byte], (pixels_per_byte-1-i)*bits)   # pack pixels and add to result

    return c