本文实例讲述了Python图像处理之简单画板实现方法。分享给大家供大家参考，具体如下：

Python图像处理也是依赖opencv的Python接口实现的，Python语言简单易懂，简洁明了。本次实现画板涂鸦，一个是在里面画矩形，还有画线。其他也都可以扩展，本案例只做例程，思路是对鼠标事件的处理，以及滚动条调节颜色处理。鼠标事件就包含有左键按下，以及释放事件的处理。

import cv2
import numpy as np
# null function
def nothing(x):
 pass
Drawing = False
Mode = True
IX,IY = -1,-1
def drawCircle(Event,X,Y,Flags,Param):
 R = cv2.getTrackbarPos('R','Image')
 G = cv2.getTrackbarPos('G','Image')
 B = cv2.getTrackbarPos('B','Image')
#get color value
 Color = (B,G,R);
 global IX,IY,Drawing,Mode
 if Event == cv2.EVENT_LBUTTONDOWN:
 Drawing = True
 IX,IY = X,Y
 elif Event == cv2.EVENT_MOUSEMOVE and Flags == cv2.EVENT_FLAG_LBUTTON:
 if Drawing == True:
 if Mode == True:
 cv2.rectangle(Img,(IX,IY),(X,Y),Color,-1)
 else:
 cv2.circle(Img,(X,Y),3,Color,-1);
 elif Event == cv2.EVENT_LBUTTONUP:
 Drawing = False
#create image with 3 chanels
Img = np.zeros((660,660,3),np.uint8)
#create window
cv2.namedWindow('Image')
#create track bar, range for 0~255
cv2.createTrackbar('R','Image',0,255,nothing)
cv2.createTrackbar('G','Image',0,255,nothing)
cv2.createTrackbar('B','Image',0,255,nothing)
#set mouse ack
cv2.setMouseCallback('Image',drawCircle)
while(1):
 cv2.imshow('Image',Img)
 k = cv2.waitKey(10)&0xFF
 #switch draw mode
 if k == ord('m'):
 Mode = not Mode
 elif k == 27:
 break
#you must destroy all of sources
cv2.destroyAllWindows()

最后的效果图如下：

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