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

def draw_rect(rect):
# 在im画布上画矩形rect
    im = np.zeros([240, 320], dtype = np.uint8)
    cv2.polylines(im, [rect], 1, 255)
    plt.imshow(im)
    plt.show()

def rotate_rect(rect, angle):
# 输出rect旋转后的矩形四个点的坐标，angle为正及顺时针旋转，为负及逆时针旋转
    (x,y),(w,h),a = cv2.minAreaRect(rect)
    rect_r = ((x,y), (w,h), a+angle)
    return cv2.boxPoints(rect_r).astype(np.int32)
# rect = np.array([[100, 50], [150, 50], [150, 150], [100, 150]], dtype=np.int32)



def rect2point9(rect):
    point9 = []
    rect_x = np.mean(rect[:, 0])
    rect_y = np.mean(rect[:, 1])
    point9.append([rect_x, rect_y])
    for p in range(len(rect)):
        point9.append(rect[p])
        point9.append((rect[p,:]+rect[(p+1)%len(rect),:])/2)
    return np.array(point9)

# 旋转矩形框 x y w h a
rect_a = ((100,100), (50,100), 45)
draw_rect(cv2.boxPoints(rect_a).astype(np.int32))
# 4个点 x y
rect_xy = cv2.boxPoints(rect_a).astype(np.float32)
print(rect_xy)


# 9个点 x y
point9 = rect2point9(rect_xy)
print(point9)

#旋转矩形框 x y w h a
rect_a = cv2.minAreaRect(point9)
print(rect_a)

#draw_rect(cv2.boxPoints(rect_a).astype(np.int32))