import cv2 as cv
import numpy as np
import h5py as h5

# Extract letter from a bounding box
def extract_bb(img, bb):
    # Get the bounding box
    rect = cv.minAreaRect(bb.astype(np.float32).transpose())
    # will be useful later, map center and size to ints
    center, size = tuple(map(int, rect[0])), tuple(map(int, rect[1]))
    # Calculate rotation matrix and rotate the image
    rot_matrix = cv.getRotationMatrix2D(center, rect[2], 1)
    rot_img = cv.warpAffine(img, rot_matrix, (img.shape[1], img.shape[0]))
    # bounding box is now axis aligned, and we can crop it
    print(size)
    cropped = cv.getRectSubPix(rot_img, size, center)
    return cropped