import matplotlib.pyplot as plt
import math
def convert_center_to_leftdown(x_cord, y_cord, angle, width, height):
    xp = x_cord-(math.sqrt(width**2+height**2)/2)*math.cos(math.atan2(height, width)+angle/180*math.pi)
    yp = y_cord-(math.sqrt(width**2+height**2)/2)*math.sin(math.atan2(height, width)+angle/180*math.pi)
    return xp, yp
fig1 = plt.figure()   # 確保正方形在屏幕上顯示一致，固定figure的長(zhǎng)寬相等
axes1 = fig1.add_subplot(1, 1, 1)
# 輸入矩形中心坐標(biāo)，矩形方位角(逆時(shí)針為正)以及矩形的寬與高即可繪制矩形
x = 0.5
y = 0.5
phi = -30
w = 0.2
h = 0.1
xp, yp = convert_center_to_leftdown(x, y, phi, w, h)
square = plt.Rectangle(xy=(xp, yp), width=w, height=h, alpha=0.8, angle=phi)
axes1.add_patch(square)  # 把圖形加載到繪制區(qū)域
axes1.axis('equal')
axes1.grid()
plt.show()

cv2.rectangle(img, pt1, pt2, color[, thickness[, lineType[, shift]]])?

import numpy as np
import cv2 as cv
img = np.zeros((320, 320, 3), np.uint8) #生成一個(gè)空灰度圖像
print img.shape # 輸出：(320, 320, 3)
# 矩形左上角和右上角的坐標(biāo)，繪制一個(gè)綠色矩形
ptLeftTop = (60, 60)
ptRightBottom = (260, 260)
point_color = (0, 255, 0) # BGR
thickness = 1?
lineType = 4
cv.rectangle(img, ptLeftTop, ptRightBottom, point_color, thickness, lineType)
# 繪制一個(gè)紅色矩形
ptLeftTop = (120, 100)
ptRightBottom = (200, 150)
point_color = (0, 0, 255) # BGR
thickness = 1
lineType = 8
cv.rectangle(img, ptLeftTop, ptRightBottom, point_color, thickness, lineType)
cv.namedWindow("AlanWang")
cv.imshow('AlanWang', img)
cv.waitKey (10000) # 顯示 10000 ms 即 10s 后消失
cv.destroyAllWindows()