Python opencv 绘图

renderImg = np.zeros((700,700, 4),dtype=np.uint8)
renderImg = cv.polylines(renderImg,lines, 2, (0,0, 255, 250), 2)
#renderImg = cv.circle(renderImg, (255, 255), 100, (0, 0, 255, 255) , 5) 
cv.imwrite("./renderImg.png", renderImg) 

renderImg = np.zeros((700,700, 3),dtype=np.uint8)
renderImg = cv.polylines(renderImg,lines, 2, (0,0,250), 2)
cv.imwrite("./renderImg.png", renderImg) 

下边的都不能错