rotate and shear without cropping

transform.py

def rotate_and_shear_image(im, angle=30, x_shear=.7, y_shear=.7):
    """
    Rotates an image (angle in degrees) and expands image to avoid cropping
    change from https://stackoverflow.com/a/51109152
    """
    #print(im.shape)
    height, width = im.shape[:2] # image shape has 3 dimensions
    image_center = (width/2, height/2) # getRotationMatrix2D needs coordinates in reverse order (width, height) compared to shape

    rotation_im = cv2.getRotationMatrix2D(image_center, angle, 1.)

    rotation_im[0,1] += x_shear
    rotation_im[1,0] += y_shear

    # rotation calculates the cos and sin, taking absolutes of those.
    abs_cos_x = abs(rotation_im[0,0]) 
    abs_sin_x = abs(rotation_im[0,1])
    abs_cos_y = abs(rotation_im[1,0]) 
    abs_sin_y = abs(rotation_im[1,1])

    # find the new width and height bounds
    bound_w = int(width * abs_cos_x +  height *  abs_sin_x )
    bound_h = int(height * abs_sin_y  + width * abs_cos_y )

    # subtract old image center (bringing image back to origo) and adding the new image center coordinates
    rotation_im[0, 2] += bound_w/2 - image_center[0] - image_center[1] * x_shear
    rotation_im[1, 2] += bound_h/2 - image_center[1] - image_center[0] * y_shear

    board_mode = cv2.BORDER_CONSTANT
    color = (randint(230,250), randint(230,250), randint(230,250))
    
    # rotate image with the new bounds and translated rotation imrix
    im = cv2.warpAffine(im, rotation_im, (bound_w, bound_h), flags=cv2.INTER_LINEAR, borderMode=board_mode, borderValue=color)
    im = cv2.resize(im, (WEIGHT, HEIGHT))

    #print(rotated_im.shape)
    return im
  
  if __name__ == '__main__':
    im = cv2.imread(your_image_file)
    im = rotate_and_shear_image(im, angle=30, x_shear=.5, y_shear=.4)