floyd-steinberg dithering of a single channel uint8 image

floyd_steinberg.py

def floyd_steinberg_dither(data):

    result = data.astype(np.float64)

    fs_matrix = np.array( (
        ( np.nan, np.nan, 7/16 ),
        ( 3/16, 5/16, 1/16),
        ), dtype=np.float64 );

    fs_mask = np.array( (
        (False, False, True),
        (True, True, True),
        ), dtype=np.bool)

    rows, cols = data.shape
    for y in range(1,rows-1):
        for x in range(1, cols-1):

            val = result[y, x]
            new_val = (val >= 127) and 255 or 0
            error = val - new_val
            result[y, x] = new_val

            view = result[y:y+2, x-1:x+2]
            new_view = view + error * fs_matrix
            np.putmask(view, fs_mask, new_view)

    return np.clip(result, 0, 255).astype(np.uint8)