#!/bin/env python

import sys
import cv2
import math
import numpy as np
import matplotlib.pyplot as plt

def correct(): 
  img = cv2.imread(sys.argv[1])
  rows,cols,ch = img.shape

  pts1 = np.float32([[98, 786],[20, 3268],[1800, 3268],[1798, 850]])

  ratio=1.6
  cardH=math.sqrt((pts1[2][0]-pts1[1][0])*(pts1[2][0]-pts1[1][0])+(pts1[2][1]-pts1[1][1])*(pts1[2][1]-pts1[1][1]))
  cardW=ratio*cardH;
  pts2 = np.float32([[pts1[0][0],pts1[0][1]], [pts1[0][0]+cardW, pts1[0][1]], [pts1[0][0]+cardW, pts1[0][1]+cardH], [pts1[0][0], pts1[0][1]+cardH]])

  M = cv2.getPerspectiveTransform(pts1,pts2)

  offsetSize=500
  transformed = np.zeros((int(cardW+offsetSize), int(cardH+offsetSize)), dtype=np.uint8);
  dst = cv2.warpPerspective(img, M, transformed.shape)

  plt.subplot(121),plt.imshow(img),plt.title('Input')
  plt.subplot(122),plt.imshow(dst),plt.title('Output')
  plt.show()

if __name__ == "__main__":
  correct()