lab1.py

import cv2
import math

# Input example: /home/b1rd/pyexample/Berneys4.jpg 45 0.5 1

def transform(image, a, c, i):
    img = cv2.imread(image)
    rows,cols, ch = img.shape

    croppedWidth, croppedHeight = map(int, rect_max_area(cols, rows, math.radians(a)))

    dst = crop_around_center(rotate_image(img, a), croppedWidth, croppedHeight)

    modifiedWidth, modifiedHeight = int(dst.shape[1]*c), int(dst.shape[0]/c)
    stretched = cv2.resize(dst, (modifiedWidth, modifiedHeight))

    cv2.imwrite('/home/b1rd/pyexample/rotated.jpg', dst)
    cv2.imwrite('/home/b1rd/pyexample/resized.jpg', stretched)
    
    interpolated_img = cv2.resize(dst, (modifiedWidth, modifiedHeight), interpolation=i)
    cv2.imwrite('/home/b1rd/pyexample/interpolated.bmp', interpolated_img)

    cv2.imshow('Rotated by '+str(a)+' degrees',dst)
    cv2.imshow('Stretched with coefficient = ' + str(c), stretched)

    cv2.waitKey(0)
    cv2.destroyAllWindows()

def crop_around_center(image, width, height):
    image_size = (image.shape[1], image.shape[0])
    image_center = (int(image_size[0] * 0.5), int(image_size[1] * 0.5))

    if(width > image_size[0]):
        width = image_size[0]

    if(height > image_size[1]):
        height = image_size[1]

    x1 = int(image_center[0] - width * 0.5)
    x2 = int(image_center[0] + width * 0.5)
    y1 = int(image_center[1] - height * 0.5)
    y2 = int(image_center[1] + height * 0.5)

    return image[y1:y2, x1:x2]  

def rotate_image(image, angle):
    height, width, ch = image.shape
    height_big = height * 2
    width_big = width * 2
    image_big = cv2.resize(image, (width_big, height_big))
    image_center = (width_big/2, height_big/2)#rotation center
    rot_mat = cv2.getRotationMatrix2D(image_center,angle, 0.5)
    result = cv2.warpAffine(image_big, rot_mat, (width_big, height_big), flags=cv2.INTER_LINEAR, borderMode=cv2.BORDER_CONSTANT, borderValue=(255, 255, 255, 255))
    return result

def rect_max_area(w, h, angle):
  if w <= 0 or h <= 0:
    return 0,0

  width_is_longer = w >= h
  side_long, side_short = (w,h) if width_is_longer else (h,w)

  sin_a, cos_a = abs(math.sin(angle)), abs(math.cos(angle))
  if side_short <= 2.*sin_a*cos_a*side_long:
    x = 0.5*side_short
    wr,hr = (x/sin_a,x/cos_a) if width_is_longer else (x/cos_a,x/sin_a)
  else:
    cos_2a = cos_a*cos_a - sin_a*sin_a
    wr,hr = (w*cos_a - h*sin_a)/cos_2a, (h*cos_a - w*sin_a)/cos_2a

  return wr,hr


def main():
    input = raw_input().split()

    img, angle, coeff, interp = str(input[0]), int(input[1]), float(input[2]), int(input[3])
    print img, angle, coeff, interp
    print(transform(img, angle, coeff, interp))

if __name__ == "__main__":
    main()