# -*- coding: utf-8 -*-

"""

Created on Sun Nov 4 20:28:33 2018

@author: mark

"""

import cv2

import numpy as np

from argparse import ArgumentParser

from to_read_pfm import readPFM

parser = ArgumentParser();

parser.add_argument("flow_path", help="where to get the optical flow");

parser.add_argument("img0_path", help="where to get the original image0 as base");

parser.add_argument("-VL", help="optical vector length", dest="length", type=int, default=1);

parser.add_argument("-LW", help="line width", dest="line_width", type=int, default=2);

parser.add_argument("-SY", help="show an optical flow between how many rows", dest="show_Y", type=int, default=50);

parser.add_argument("-SX", help="show an optical flow between how many columns", dest="show_X", type=int, default=50);

parser.add_argument("-ON", help="output name", dest="output_name", default='output.jpg');

args = parser.parse_args();

error_flag = False;

if '.pfm' in args.flow_path:

flow, scale = readPFM(args.flow_path);#assume y direction is in dimension 0, and x in dimension 1.

elif '.npy' in args.flow_path:

flow = np.load(args.flow_path);

else:

print('not support optical flow file!');

error_flag = True;

if error_flag == False:

original_image = cv2.imread(args.img0_path);

vector_length = args.length;

line_width = args.line_width;

show_interval_y = args.show_Y;#(vertical direction)

show_interval_x = args.show_X;#(horizontal direction)

for y in range(0, flow.shape[0]):#in for loop using the opencv coordinate system

if y % show_interval_y == 0:

for x in range(0, flow.shape[1]):

if x % show_interval_x == 0:

vector = flow[y][x] * vector_length;#but in drawing function, using different way to understand x and y

cv2.line(original_image, (x, y), (int(np.round(x + vector[0])), int(np.round(y + vector[1]))), (0, 255, 0), line_width);

cv2.circle(original_image, (x, y), 1, (255, 255, 255), -1);#that's why using (x,y) not (y,x)

cv2.imwrite(args.output_name, original_image);

cv2.imshow("show", original_image);

cv2.waitKey(0);

cv2.destroyAllWindows();

else:

print('exit with no output.');