import tensorflow as tf
import numpy as np
import cv2

def visualize_attention_map(attention_map):

    """
    The attention map is a matrix ranging from 0 to 1, where the greater the value,
    the greater attention is suggests.
    :param attention_map: np.numpy matrix hanging from 0 to 1
    :return np.array matrix with rang [0, 255]
    """    
    attention_map_color = np.zeros(
        shape=[attention_map.shape[0], attention_map.shape[1], 3],
        dtype=np.uint8    
    )

    red_color_map = np.zeros(
        shape=[attention_map.shape[0], attention_map.shape[1]],
        dtype=np.uint8
    ) + 255    
    
    red_color_map = red_color_map * attention_map
    red_color_map = np.array(red_color_map, dtype=np.uint8)
    
    attention_map_color[:, :, 2] = red_color_map    

    return attention_map_color