OpenCV鼠标事件

# Author：Winter Liu is coming!
import cv2 as cv
import numpy as np


# 鼠标回调函数，当发生鼠标事件，调用此函数，传递5个参数
def draw_demo(event, x, y, flags, params):
    # 左键、右键、左键双击
    # 对应圆、矩形、椭圆形
    if event == cv.EVENT_FLAG_LBUTTON:
        cv.circle(image, (x, y), 20, (0, 0, 255), -1)
    elif event == cv.EVENT_FLAG_RBUTTON:
        cv.rectangle(image, (x, y), (x+20, y+20), (0, 255, 0), 2)
    elif event == cv.EVENT_LBUTTONDBLCLK:
        cv.ellipse(image, (x, y), (50, 30), 45, 0, 360, (255, 0, 0), 2)


# 查看OpenCV中可识别事件
events = [i for i in dir(cv) if 'EVENT' in i]
for e in events:
    print(e)
# 使用numpy创建纯色图形，全白（全黑）
image = (np.ones((512, 512, 3), np.uint8))*255
# image = np.zeros((512, 512, 3), np.uint8)
cv.namedWindow("PIC")
# 设置鼠标回调
cv.setMouseCallback('PIC', draw_demo)

while 1:
    cv.imshow("PIC", image)
    if cv.waitKey(20) == 27:
        break
cv.destroyAllWindows()