OpenCV-Python系列·第十七集：键盘事件

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Tip：键盘响应.

# -*- coding: utf-8 -*-
"""
Created on Sun Aug 26 11:14:19 2018

@author: Miracle
"""

import cv2
#打开默认摄像头
cap = cv2.VideoCapture(0)
#当前状态、之前状态
cur_flag = -1
pre_flag = -1
#判断是否打开
if not cap.isOpened():
    raise IOError('Cannot open webcam!')
#无限循环
while True:
    #每一帧
    ret,frame = cap.read()
    frame = cv2.resize(frame,None,fx = 1.25,fy = 1.05,
                       interpolation = cv2.INTER_CUBIC)
    #获取键盘事件
    flag = cv2.waitKey(1)
    #Esc，退出
    if flag == 27:
        break
    #判断是否按下其他键
    if flag > -1 and flag != pre_flag:
        cur_flag = flag
    pre_flag = flag
    
    #响应事件
    if cur_flag == ord('g'):
        output = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    elif cur_flag == ord('y'):
        output = cv2.cvtColor(frame,cv2.COLOR_BGR2YUV)
    elif cur_flag == ord('h'):
        output = cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)
    else:
        output = frame
    #显示
    cv2.imshow('webcam',output)
#关闭
cap.release()
cv2.destroyAllWindows()