python opencv使用回调函数-白红宇

python opencv使用回调函数

阅读量：3902 次

发布时间：2019-05-23

本文共 1234 字，大约阅读时间需要 4 分钟。

1，使用回调函数绘制标准的圆：

鼠标左键按下画圆

import cv2import numpy as npevents = [i for i in dir(cv2) if "EVENT" in i]print(events)img = np.zeros((720,640,3), np.uint8)def draw_circle(event,x,y,flags,param):    if event == cv2.EVENT_LBUTTONDOWN:        cv2.circle(img,(x,y),60,(255,0,0),-1)cv2.namedWindow('image')cv2.setMouseCallback('image', draw_circle)while True:    cv2.imshow('image', img)    key = cv2.waitKey(1)    if key == ord('q') or key == 27:        breakcv2.destroyAllWindows()

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2、自定义绘制矩形：

import cv2import numpy as npevents = [i for i in dir(cv2) if "EVENT" in i]print(events)xi,yi = -1,-1drawing = Falseimg = np.zeros((720,640,3), np.uint8)def draw_circle(event,x,y,flags,param):    global xi, yi, drawing    if event == cv2.EVENT_LBUTTONDOWN:        drawing =True        xi,yi =x,y    elif event == cv2.EVENT_MOUSEMOVE:        if drawing:            cv2.rectangle(img,(xi,yi),(x,y),(0,255,0),-1)    elif event == cv2.EVENT_LBUTTONUP:        if drawing:            cv2.rectangle(img,(xi,yi),(x,y),(0,255,0),-1)            drawing = Falsecv2.namedWindow('image')cv2.setMouseCallback('image', draw_circle)while True:    cv2.imshow('image', img)    key = cv2.waitKey(1)    if key == ord('q') or key == 27:        breakcv2.destroyAllWindows()

在这里插入图片描述