在图上画一个圆

cv2.circle(img, center, radius, color, thickness=1, lineType=8, shift=0) → NoneDraws a circle.Parameters: img (CvArr) – Image where the circle is drawncenter (CvPoint) – Center of the circleradius (int) – Radius of the circlecolor (CvScalar) – Circle colorthickness (int) – Thickness of the circle outline if positive, otherwise this indicates that a filled circle is to be drawnlineType (int) – Type of the circle boundary, see Line descriptionshift (int) – Number of fractional bits in the center coordinates and radius value