OpenCV-Python系列·第十七集：鍵盤事件

Tip：鍵盤響應.

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

@author: Miracle
"""

import cv2
#打開默認攝像頭
cap = cv2.VideoCapture(0)
#當前狀態、之前狀態
cur_flag = -1
pre_flag = -1
#判斷是否打開
if not cap.isOpened():
    raise IOError('Cannot open webcam!')
#無限循環
while True:
    #每一幀
    ret,frame = cap.read()
    frame = cv2.resize(frame,None,fx = 1.25,fy = 1.05,
                       interpolation = cv2.INTER_CUBIC)
    #獲取鍵盤事件
    flag = cv2.waitKey(1)
    #Esc，退出
    if flag == 27:
        break
    #判斷是否按下其他鍵
    if flag > -1 and flag != pre_flag:
        cur_flag = flag
    pre_flag = flag
    
    #響應事件
    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
    #顯示
    cv2.imshow('webcam',output)
#關閉
cap.release()
cv2.destroyAllWindows()