effects.py 文件源码

def wormhole(tensor, shape, kink, input_stride, alpha=1.0):
    """
    Apply per-pixel field flow. Non-iterative.

    :param Tensor tensor:
    :param list[int] shape:
    :param float kink: Path twistiness
    :param float input_stride: Maximum pixel offset
    :return: Tensor
    """

    height, width, channels = shape

    values = value_map(tensor, shape)

    degrees = values * 360.0 * math.radians(1) * kink
    # stride = values * height * input_stride
    stride = height * input_stride

    x_index = tf.cast(row_index(shape), tf.float32)
    y_index = tf.cast(column_index(shape), tf.float32)

    x_offset = (tf.cos(degrees) + 1) * stride
    y_offset = (tf.sin(degrees) + 1) * stride

    x = tf.cast(x_index + x_offset, tf.int32) % width
    y = tf.cast(y_index + y_offset, tf.int32) % height

    luminosity = tf.square(tf.reshape(values, [height, width, 1]))

    out = normalize(tf.scatter_nd(offset_index(y, height, x, width), tensor * luminosity, tf.shape(tensor)))

    return blend(tensor, tf.sqrt(out), alpha)