Python 4.图片上绘制直线，圆，椭圆，文字，多边形 OpenCV Linux

import cv2
import numpy as np
from matplotlib import pylab as plt


img = cv2.imread('pic1.png', 1)

#plt.imshow(img, cmap = 'gray', interpolation = 'bicubic')
#plt.xticks([]),plt.yticks([])
#plt.show()

cv2.line(img, (0,0),(490,490),(250,0,0),10)                 #plot line
cv2.rectangle(img, (0,0),(495,495),(250,155,20),5)          #plot rectangle
cv2.circle(img, (250, 250), 50, (200,100,100),-6)           #plot circle
cv2.ellipse(img, (250, 250), (200, 50), 0, 0, 180, 200, -1) #plot ellipse

pts = np.array([[10,5],[20,30],[70,20],[50,10]],np.int32)# plot polygon
pts = pts.reshape((-1,1,2))
img = cv2.polylines(img,[pts],True,(0,255,255))

font = cv2.FONT_HERSHEY_SCRIPT_SIMPLEX
cv2.putText(img, 'Opencv', (10, 400), font, 4, (255, 255, 255), 2) #put word on image

cv2.imshow('image', img)
cv2.imwrite('pic1.jpg', img) #保存图片而且可以用于转换格式
cv2.waitKey(0)               #等待按键反应
cv2.destroyAllWindows()