util.py 文件源码

def mask_func(pattern):
    """
    Return the mask function for the given mask pattern.
    """
    if pattern == 0:   # 000
        return lambda i, j: (i + j) % 2 == 0
    if pattern == 1:   # 001
        return lambda i, j: i % 2 == 0
    if pattern == 2:   # 010
        return lambda i, j: j % 3 == 0
    if pattern == 3:   # 011
        return lambda i, j: (i + j) % 3 == 0
    if pattern == 4:   # 100
        return lambda i, j: (math.floor(i / 2) + math.floor(j / 3)) % 2 == 0
    if pattern == 5:  # 101
        return lambda i, j: (i * j) % 2 + (i * j) % 3 == 0
    if pattern == 6:  # 110
        return lambda i, j: ((i * j) % 2 + (i * j) % 3) % 2 == 0
    if pattern == 7:  # 111
        return lambda i, j: ((i * j) % 3 + (i + j) % 2) % 2 == 0
    raise TypeError("Bad mask pattern: " + pattern)  # pragma: no cover