__author__ = 'ding'
'''
完整的图像预处理案例
'''
import tensorflow as tf
import numpy as np
import matplotlib.pyplot as plt


def distort_color(image, color_ordering=0):
    if color_ordering == 0:
        image = tf.image.random_brightness(image, max_delta=32. / 255.)
        image = tf.image.random_saturation(image, lower=0.5, upper=1.5)
        image = tf.image.random_hue(image, max_delta=0.2)
        image = tf.image.random_contrast(image, lower=0.5, upper=1.5)
    elif color_ordering == 1:
        image = tf.image.random_saturation(image, lower=0.5, upper=1.5)
        image = tf.image.random_brightness(image, max_delta=32. / 255.)
        image = tf.image.random_contrast(image, lower=0.5, upper=1.5)
        image = tf.image.random_hue(image, max_delta=0.2)
    return tf.clip_by_value(image, 0.0, 1.0)


def preprocess_for_train(image, height, width, bbox):
    if bbox is None:
        bbox = tf.constant([0.0, 0.0, 1.0, 1.0], dtype=tf.float32, shape=[1, 1, 4])
    if image.dtype != tf.float32:
        image = tf.image.convert_image_dtype(image, dtype=tf.float32)

    bbox_begin, bbox_size, _ = tf.image.sample_distorted_bounding_box(
        tf.shape(image), bounding_boxes=bbox, min_object_covered=0.1
    )
    distort_image = tf.slice(image, bbox_begin, bbox_size)
    distort_image = tf.image.resize_images(
        distort_image, (height, width), method=np.random.randint(4)
    )
    distort_image = tf.image.random_flip_left_right(distort_image)
    distort_image = distort_color(distort_image, np.random.randint(2))
    return distort_image


image_raw_data = tf.gfile.GFile('./path/to/picture1.jpeg', 'rb').read()
with tf.Session() as sess:
    image_data = tf.image.decode_jpeg(image_raw_data)
    boxes = tf.constant([[[0.05, 0.05, 0.9, 0.7], [0.35, 0.47, 0.5, 0.56]]])

    for i in range(6):
        result = preprocess_for_train(image_data, 299, 299, boxes)
        plt.figure(i)
        plt.imshow(result.eval())
    plt.show()